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Juyin halittar ƙwayoyin cuta na ƙwayoyin cuta ya haɗa da daidaitawa tsakanin zaɓin yanayi, wanda ke haifar da haɓakar ƙwayoyin cuta, da ɗumbin ƙwayoyin cuta, wanda ke sa ƙwayoyin cuta su rasa ƙwayoyin cuta da tara maye gurbi.Anan, don fahimtar yadda wannan maganin ya faru akan sikelin macromolecule guda ɗaya, mun bayyana tsarin cryo-EM na ribosome na Encephalitozoon cuniculi, kwayar halitta eukaryotic tare da ɗayan mafi ƙarancin kwayoyin halitta a yanayi.Matsakaicin raguwar rRNA a cikin E. cuniculi ribosomes yana tare da canje-canjen tsarin da ba a taɓa ganin irinsa ba, kamar juyin halittar mahaɗan rRNA da ba a san su ba da rRNA ba tare da kumbura ba.Bugu da kari, E. cuniculi ribosome ya tsira daga asarar guntuwar rRNA da sunadarai ta hanyar haɓaka ikon yin amfani da ƙananan ƙwayoyin cuta azaman kwaikwayo na ɓarna rRNA da sunadarai.Gabaɗaya, mun nuna cewa sifofin kwayoyin da aka dade ana tunanin za a rage su, sun lalace, kuma suna ƙarƙashin gurɓatattun maye gurbi suna da hanyoyin ramawa da yawa waɗanda ke sa su aiki duk da matsananciyar ƙanƙancewar ƙwayoyin cuta.
Saboda yawancin rukunin ƙwayoyin cuta na ƙwayoyin cuta suna da kayan aikin ƙwayoyin cuta na musamman don amfani da rundunoninsu, sau da yawa dole ne mu samar da magunguna daban-daban don ƙungiyoyi daban-daban na parasites1,2.Duk da haka, sababbin shaidu sun nuna cewa wasu sassa na juyin halitta na parasite suna haɗuwa da juna kuma galibi ana iya hasashensu, suna nuna yuwuwar tushe don faɗuwar hanyoyin warkewa a cikin ƙananan ƙwayoyin cuta3,4,5,6,7,8,9.
Ayyukan da suka gabata sun gano yanayin juyin halitta gama gari a cikin ƙananan ƙwayoyin cuta da ake kira rage genome ko lalata genome10,11,12,13.Bincike na yanzu ya nuna cewa lokacin da ƙananan ƙwayoyin cuta suka bar salon rayuwarsu ta kyauta kuma suka zama parasites na cikin salula (ko endosymbionts), kwayoyin halittarsu suna yin jinkirin amma mai ban mamaki metamorphoses sama da miliyoyin shekaru9,11.A cikin wani tsari da aka sani da lalata ƙwayoyin halitta, ƙwayoyin cuta na ƙwayoyin cuta suna tara maye gurbi waɗanda ke juyar da yawancin kwayoyin halitta masu mahimmanci a baya zuwa pseudogenes, wanda ke haifar da asara sannu a hankali da rugujewar maye14,15.Wannan rugujewar na iya lalata kusan kashi 95% na kwayoyin halittar da ke cikin tsofaffin kwayoyin halitta na cikin salula idan aka kwatanta da nau'in rayuwa masu 'yanci masu alaka.Don haka, juyin halittar kwayoyin cuta a cikin salula wani yaki ne tsakanin runduna guda biyu masu gaba da juna: zabin dabi'ar Darwiniyanci, wanda ke haifar da ingantuwar kwayoyin cuta, da rugujewar kwayoyin halitta, da jefa kwayoyin cuta cikin mantuwa.Ba a fayyace yadda kwayar cutar ta yi nasarar fitowa daga wannan yakin da kuma ci gaba da gudanar da ayyukanta na kwayoyin halitta ba.
Ko da yake ba a fahimci tsarin ruɓewar kwayoyin halitta ba, da alama yana faruwa ne saboda yawan yaɗuwar kwayoyin halitta.Saboda parasites suna rayuwa a cikin ƙanana, asexual, da iyakantattun al'ummomi, ba za su iya kawar da maye gurbi wanda wani lokaci yakan faru yayin kwafin DNA.Wannan yana haifar da tarin sauye-sauye masu cutarwa da ba za a iya jujjuya su ba da raguwar kwayoyin halitta.A sakamakon haka, parasites ba kawai ya rasa kwayoyin halitta waɗanda ba su da mahimmanci don rayuwa a cikin yanayin cikin salula.Rashin iyawar al'ummomi don kawar da maye gurbi na lokaci-lokaci shine ke sa waɗannan maye gurbi su taru a ko'ina cikin kwayoyin halitta, gami da mahimman kwayoyin halittarsu.
Yawancin fahimtarmu na yanzu game da raguwar kwayoyin halitta ya dogara ne kawai akan kwatancen jerin kwayoyin halitta, tare da ƙarancin kulawa ga canje-canje a ainihin kwayoyin halitta waɗanda ke yin ayyukan kula da gida da kuma zama maƙasudin magunguna.Nazarin kwatancen sun nuna cewa nauyin maye gurbi na intracellular intracellular yana bayyana yana haifar da sunadaran sunadarai da acid nucleic don ɓarna da tarawa, yana mai da su ƙarin dogaro da chaperone da haɓaka ga zafi19,20,21,22,23.Bugu da kari, daban-daban parasites — juyin halitta mai zaman kanta wani lokaci ya rabu da kusan shekaru biliyan 2.5 - sun sami irin wannan asarar cibiyoyin kula da inganci a cikin haɗin furotin su5,6 da hanyoyin gyaran DNA24.Duk da haka, an san kadan game da tasirin salon salula akan duk sauran kaddarorin macromolecules na salula, gami da karbuwar kwayoyin halitta zuwa karuwar nauyin maye gurbi.
A cikin wannan aikin, don ƙarin fahimtar juyin halittar sunadarai da acid nucleic na microorganisms na ciki, mun ƙaddara tsarin ribosomes na intracellular parasite Encephalitozoon cuniculi.E. cuniculi wata kwayar cuta ce mai kama da naman gwari wacce ke cikin rukunin microsporidia na parasitic wadanda ke da kananan kwayoyin halittar eukaryotic da ba a saba gani ba don haka ana amfani da su azaman kwayoyin halitta don yin nazarin lalata kwayoyin halitta25,26,27,28,29,30.Kwanan nan, an ƙaddara tsarin ribosome na cryo-EM don matsakaicin raguwar kwayoyin halittar Microsporidia, Paranosema locustae, da Vairimorpha necatrix31,32 (~ 3.2 Mb genome).Waɗannan sifofin suna ba da shawarar cewa ana samun ramawa wasu asarar haɓakar rRNA ta haɓaka sabbin alaƙa tsakanin sunadaran ribosomal makwabta ko kuma samun sabbin sunadaran msL131,32 ribosomal.Nau'o'in Encephalitozoon (genome ~ 2.5 miliyan bp), tare da danginsu na kusa Ordospora, suna nuna matuƙar ƙimar rage genome a cikin eukaryotes - suna da ƙasa da 2000 na ƙwayoyin furotin, kuma ana sa ran cewa ribosomes ɗin su ba kawai ba su da gutsuttsuran haɓakar rRNA (rashin rRNA zuwa rashi na ribosomesbosom da ƙwayoyin ribosomesbosom na ribosomesbosom) na homologues a cikin E. cuniculi genome26,27,28.Saboda haka, mun kammala cewa E. cuniculi ribosome zai iya bayyana dabarun da ba a san su ba don daidaita kwayoyin halitta zuwa lalata kwayoyin halitta.
Tsarin mu na cryo-EM yana wakiltar mafi ƙarancin eukaryotic cytoplasmic ribosome da za a iya siffanta shi kuma yana ba da haske game da yadda babban matakin rage genome ya shafi tsari, taro, da juyin halitta na injinan kwayoyin da ke da alaƙa da tantanin halitta.Mun gano cewa E. cuniculi ribosome ya saba wa yawancin ka'idodin da aka kiyaye sosai na nadawa RNA da taro ribosome, kuma ya gano wani sabon furotin ribosomal wanda ba a san shi ba.Ba zato ba tsammani, mun nuna cewa microsporidia ribosomes sun samo asali ikon ɗaure ƙananan ƙwayoyin cuta, kuma suna tunanin cewa gungumen azaba a cikin rRNA da sunadaran suna haifar da sabbin abubuwan juyin halitta waɗanda a ƙarshe zasu ba da halaye masu amfani akan ribosome.
Don inganta fahimtarmu game da juyin halittar sunadarai da acid nucleic a cikin kwayoyin halitta, mun yanke shawarar ware E. cuniculi spores daga al'adun kwayoyin dabbobi masu shayarwa don tsaftace ribosomes da sanin tsarin waɗannan ribosomes.Yana da wahala a sami adadi mai yawa na microsporidia na parasitic saboda ba za a iya al'adar microsporidia a cikin matsakaicin abinci ba.Maimakon haka, suna girma kuma suna haifuwa kawai a cikin tantanin halitta.Saboda haka, don samun E. cuniculi biomass don tsarkakewar ribosome, mun kamu da layin ƙwayar koda na mammalian RK13 tare da E. cuniculi spores da kuma al'adar waɗannan ƙwayoyin cuta na makonni da yawa don ba da damar E. cuniculi ya girma kuma ya ninka.Yin amfani da kwayar cutar tantanin halitta mai kusan rabin murabba'in mita, mun sami damar tsarkake kusan MG 300 na Microsporidia spores kuma mu yi amfani da su don ware ribosomes.Sa'an nan kuma muka rushe tsattsauran spores da gilashin beads kuma muka ware danye ribosomes ta amfani da stepwise polyethylene glycol fractionation na lysates.Wannan ya ba mu damar samun kusan 300 µg na raw E. cuniculi ribosomes don nazarin tsari.
Daga nan mun tattara hotunan cryo-EM ta amfani da samfuran ribosome da aka samu kuma muka sarrafa waɗannan hotuna ta amfani da abin rufe fuska da suka dace da babban ɓangaren ribosomal, ƙaramin shugaban subunit, da ƙaramin yanki.A yayin wannan tsari, mun tattara hotuna na kusan 108,000 ribosomal barbashi da lissafta hotuna cryo-EM tare da ƙuduri na 2.7 Å (Ƙarin Figures 1-3).Daga nan mun yi amfani da hotunan cryoEM don yin samfurin rRNA, furotin ribosomal, da kuma abin da ke sa hibernation Mdf1 da ke hade da E. cuniculi ribosomes (Fig. 1a, b).
a Tsarin E. cuniculi ribosome a cikin hadaddun tare da ma'aunin hibernation Mdf1 (pdb id 7QEP).b Map of hibernation factor Mdf1 hade da E. cuniculi ribosome.c Taswirar tsari na biyu yana kwatanta rRNA da aka dawo dasu a cikin nau'in Microsporidian zuwa sanannun tsarin ribosomal.Ƙungiyoyin suna nuna wurin da aka haɓaka rRNA gutsuttsura (ES) da kuma ribosome masu aiki, ciki har da wurin yanke hukunci (DC), madauki sarcinicin (SRL), da kuma peptidyl transferase center (PTC).d Yawan electron wanda yayi daidai da cibiyar peptidyl transferase na E. cuniculi ribosome yana nuna cewa wannan rukunin yanar gizon yana da tsari iri ɗaya a cikin E. cuniculi parasite da rundunoninsa, gami da H. sapiens.e, f Madaidaicin adadin wutar lantarki na cibiyar yanke hukunci (e) da tsarin tsarin cibiyar yanke hukunci (f) suna nuna cewa E. cuniculi yana da ragowar U1491 maimakon A1491 (E. coli lamba) a cikin sauran eukaryotes da yawa.Wannan canjin yana nuna cewa E. cuniculi na iya zama mai kula da maganin rigakafi waɗanda ke kaiwa wannan rukunin aiki.
Ya bambanta da tsarin da aka kafa a baya na V. necatrix da P. locustae ribosomes (dukansu tsarin suna wakiltar microsporidia iyali Nosematidae kuma suna kama da juna), 31,32 E. cuniculi ribosomes suna jurewa matakai masu yawa na rRNA da rarrabuwar furotin.Ƙarin ƙira (Ƙari Hotuna 4-6).A cikin rRNA, sauye-sauye masu ban mamaki sun haɗa da cikakkiyar asarar 25S rRNA da aka haɓaka ES12L da raguwa na h39, h41, da H18 helices (Fig. 1c, Ƙarin Hoto 4).Daga cikin sunadaran ribosomal, sauye-sauye masu ban mamaki sun haɗa da cikakkiyar asarar furotin eS30 da rage eL8, eL13, eL18, eL22, eL29, eL40, uS3, uS9, uS14, uS17, da eS7 sunadaran (Ƙarin Figures 4, 5).
Don haka, matsanancin raguwar kwayoyin halittar halittar Encephalotozoon/Ordospora yana nunawa a cikin tsarin su na ribosome: E. cuniculi ribosomes sun sami asarar abubuwan gina jiki mafi ban mamaki a cikin eukaryotic cytoplasmic ribosomes da ke ƙarƙashin sifa, kuma ba su ma da waɗannan rRNA da gutsuttsuran furotin waɗanda ke ko'ina cikin rayuwa ba kawai a cikin yanki guda uku ba.Tsarin E. cuniculi ribosome yana samar da samfurin kwayoyin halitta na farko don waɗannan canje-canje kuma yana bayyana abubuwan da suka faru na juyin halitta waɗanda aka yi watsi da su ta hanyar kwatancen genomics da nazarin tsarin ƙwayoyin ƙwayoyin cuta na ciki (Ƙarin Hoto 7).A ƙasa, mun bayyana kowane ɗayan waɗannan abubuwan da suka faru tare da yiwuwar asalinsu na juyin halitta da tasirin su akan aikin ribosome.
Sai muka gano cewa, baya ga manyan rRNA, E. cuniculi ribosomes suna da bambancin rRNA a ɗaya daga cikin wuraren da suke aiki.Kodayake peptidyl transferase cibiyar E. cuniculi ribosome yana da tsari iri ɗaya kamar sauran ribosomes eukaryotic (Fig. 1d), cibiyar ƙaddamarwa ta bambanta saboda bambancin jerin a nucleotide 1491 (E. coli lambobi, Fig. 1e, f).Wannan abin lura yana da mahimmanci saboda wurin zazzage ribosomes na eukaryotic yawanci ya ƙunshi ragowar G1408 da A1491 idan aka kwatanta da ragowar nau'in ƙwayoyin cuta A1408 da G1491.Wannan bambance-bambancen yana haifar da mabanbantan hankali na ƙwayoyin cuta da ribosomes na eukaryotic ga dangin aminoglycoside na maganin rigakafi na ribosomal da sauran ƙananan ƙwayoyin cuta waɗanda ke nufi wurin zazzagewa.A wurin yanke hukunci na E. cuniculi ribosome, ragowar A1491 an maye gurbinsu da U1491, mai yuwuwar ƙirƙirar keɓantaccen mahaɗin ɗaure don ƙananan ƙwayoyin cuta da ke niyya da wannan rukunin yanar gizon.Irin wannan bambance-bambancen A14901 kuma yana cikin wasu microsporidia kamar P. locustae da V. necatrix, yana nuna cewa ya yadu tsakanin nau'in microsporidia (Fig. 1f).
Saboda samfuran mu na E. cuniculi ribosome sun keɓe daga spores marasa aiki, mun gwada taswirar cryo-EM na E. cuniculi don daurin ribosome a baya a ƙarƙashin damuwa ko yanayin yunwa.Abubuwan da ke ɓoyewa 31,32,36,37, 38. Mun daidaita tsarin da aka kafa a baya na ribosome mai hibernating tare da taswirar cryo-EM na E. cuniculi ribosome.Don docking, S. cerevisiae ribosomes aka yi amfani da hadaddun tare da hibernation factor Stm138, fara ribosomes a hadaddun tare da Lso232 factor, da kuma V. necatrix ribosomes a hadaddun tare da Mdf1 da Mdf231 dalilai.A lokaci guda, mun sami ƙimar cryo-EM daidai da sauran factor Mdf1.Kama da Mdf1 dauri zuwa V. necatrix ribosome, Mdf1 kuma yana ɗaure zuwa E. cuniculi ribosome, inda ya toshe E site na ribosome, mai yiwuwa yana taimakawa wajen samar da ribosomes lokacin da ƙwayoyin cuta suka zama marasa aiki a kan rashin aiki na jiki (Figure 2).).
Mdf1 yana toshe rukunin E na ribosome, wanda ya bayyana yana taimakawa hana ribosome lokacin da ƙwayoyin cuta suka zama marasa aiki.A cikin tsarin E. cuniculi ribosome, mun gano cewa Mdf1 yana samar da wata hulɗar da ba a sani ba a baya tare da L1 ribosome stem, ɓangaren ribosome wanda ke sauƙaƙe sakin tRNA da aka lalata daga ribosome a lokacin haɗin furotin.Waɗannan lambobin sadarwa suna ba da shawarar cewa Mdf1 ya rabu da ribosome ta amfani da tsari iri ɗaya kamar tRNA deacetylated, yana ba da bayani mai yuwuwar yadda ribosome ke cire Mdf1 don sake kunna haɗin furotin.
Duk da haka, tsarin mu ya bayyana alamar da ba a sani ba tsakanin Mdf1 da L1 ribosome kafa (bangaren ribosome wanda ke taimakawa sakin tRNA da aka lalata daga ribosome a lokacin haɗin furotin).Musamman, Mdf1 yana amfani da lambobin sadarwa iri ɗaya da ɓangaren gwiwar gwiwar ƙwayar ƙwayar ƙwayar cuta ta tRNA (Fig. 2).Wannan ƙirar ƙwayoyin ƙwayoyin cuta da ba a san su ba a baya ya nuna cewa Mdf1 ya rabu da ribosome ta hanyar amfani da tsari iri ɗaya da tRNA deacetylated, wanda ke bayanin yadda ribosome ke kawar da wannan yanayin ɓoye don sake kunna haɗin furotin.
Lokacin gina samfurin rRNA, mun gano cewa E. cuniculi ribosome ya nade ɓangarorin rRNA da ba daidai ba, waɗanda muka kira fused rRNA (Fig. 3).A cikin ribosomes waɗanda suka mamaye sassa uku na rayuwa, rRNA na ninka cikin sifofi waɗanda galibin tushen rRNA ko dai su biyu ne kuma su ninka tare da juna ko kuma suna hulɗa da sunadaran ribosomal38,39,40.Duk da haka, a cikin E. cuniculi ribosomes, rRNAs suna da alama sun keta wannan ƙa'idar nadawa ta hanyar canza wasu helices ɗin su zuwa yankunan rRNA da ba a buɗe ba.
Tsarin H18 25S rRNA helix a cikin S. cerevisiae, V. necatrix, da E. cuniculi.Yawanci, a cikin ribosomes da ke tattare da yankuna uku na rayuwa, wannan mahaɗin yana shiga cikin helix na RNA wanda ya ƙunshi ragowar 24 zuwa 34.A cikin Microsporidia, akasin haka, wannan mai haɗin rRNA yana raguwa sannu a hankali zuwa mahaɗan masu wadatar uridine guda biyu masu ɗauke da ragowar 12 kawai.Yawancin waɗannan ragowar ana fallasa su ga kaushi.Adadin ya nuna cewa microsporidia na parasitic ya bayyana ya keta ka'idodin nadawa na rRNA, inda galibi ana haɗa sansanonin rRNA zuwa wasu tushe ko shiga cikin hulɗar rRNA-protein.A cikin microsporidia, wasu gutsuttsuran rRNA suna ɗaukar ninki mara kyau, wanda tsohon rRNA helix ɗin ya zama guntu mai ɗaci ɗaya wanda aka yi kusan a madaidaiciyar layi.Kasancewar waɗannan yankuna da ba a saba gani ba suna ba da damar microsporidia rRNA don ɗaure guntun rRNA mai nisa ta amfani da ƙaramin adadin sansanonin RNA.
Za'a iya lura da mafi kyawun misali na wannan canjin juyin halitta a cikin H18 25S rRNA helix (Fig. 3).A cikin jinsuna daga E. coli zuwa mutane, tushen wannan helix na rRNA sun ƙunshi 24-32 nucleotides, suna samar da helix maras kyau.A cikin sifofin ribosomal da aka gano a baya daga V. necatrix da P. locustae,31,32 sansanonin helix na H18 ba su da wani yanki, amma an adana haɗin haɗin ginin nucleotide.Koyaya, a cikin E. cuniculi wannan guntun rRNA ya zama mafi guntu masu haɗin gwiwa 228UUUGU232 da 301UUUUUUUUUU307.Ba kamar ɓangarorin rRNA na yau da kullun ba, waɗannan mahaɗan masu arzikin uridine ba sa murɗawa ko yin cudanya mai yawa da sunadaran ribosomal.Madadin haka, suna ɗaukar sifofin buɗaɗɗen ƙarfi da cikakkun faɗowa wanda a ciki aka shimfida madaurin rRNA kusan kai tsaye.Wannan shimfidawa na daidaitawa yana bayyana yadda E. cuniculi ke amfani da sansanonin 12 RNA kawai don cika rata na 33 Å tsakanin helices H16 da H18 rRNA, yayin da sauran nau'ikan suna buƙatar aƙalla sau biyu na sansanonin rRNA don cike gibin.
Don haka, za mu iya nuna cewa, ta hanyar nadawa mara ƙarfi, microsporidia parasitic sun haɓaka dabara don yin kwangila har ma da waɗancan sassan rRNA waɗanda ke da fa'ida a cikin nau'ikan nau'ikan nau'ikan nau'ikan rayuwa guda uku.A bayyane yake, ta hanyar tara maye gurbi waɗanda ke canza rRNA helices zuwa gajerun masu haɗin poly-U, E. cuniculi na iya ƙirƙirar gutsuttsuran rRNA da ba a saba ba waɗanda ke ɗauke da ƴan nucleotides kamar yadda zai yiwu don haɗa gutsuttsuran rRNA mai nisa.Wannan yana taimakawa bayyana yadda microsporidia ya sami raguwa mai ban mamaki a cikin ainihin tsarin kwayoyin halitta ba tare da rasa amincin tsarin su da aikin su ba.
Wani sabon abu na E. cuniculi rRNA shine bayyanar rRNA ba tare da kauri ba (Fig. 4).Bulges ne nucleotides ba tare da tushe nau'i-nau'i da karkatarwa daga RNA heliks maimakon boye a cikinsa.Yawancin rRNA protrusions suna aiki a matsayin mannen kwayoyin halitta, suna taimakawa wajen ɗaure sunadaran ribosomal ko wasu guntun rRNA.Wasu daga cikin ɓangarorin suna aiki azaman hinges, suna ba da damar helix na rRNA don jujjuya su da ninkuwa da kyau don haɓakar furotin 41.
a An rRNA protrusion (S. cerevisiae lamba) ba ya nan daga E. cuniculi ribosome tsarin, amma yanzu a cikin mafi sauran eukaryotes b E. coli, S. cerevisiae, H. sapiens, da E. cuniculi ciki ribosomes.parasites ba su da daɗaɗɗen, ɓarkewar rRNA da aka kiyaye sosai.Wadannan kauri suna daidaita tsarin ribosome;don haka, rashin su a cikin microsporidia yana nuna raguwar kwanciyar hankali na folding rRNA a cikin ƙwayoyin microsporidia.Kwatanta da P mai tushe (L7/L12 mai tushe a cikin kwayoyin cuta) yana nuna cewa asarar rRNA bumps wani lokaci ya zo daidai da bayyanar sabbin kusoshi kusa da kututturen da aka rasa.H42 helix a cikin 23S/28S rRNA yana da tsoho mai ƙuri'a (U1206 a cikin Saccharomyces cerevisiae) wanda aka kiyasta ya zama aƙalla shekaru biliyan 3.5 saboda kariyar sa a sassa uku na rayuwa.A cikin microsporia, an kawar da wannan kumburi.Duk da haka, wani sabon kumbura ya bayyana kusa da kumburin da ya ɓace (A1306 a cikin E. cuniculi).
Abin mamaki, mun gano cewa E. cuniculi ribosomes ba su da mafi yawan ɓarkewar rRNA da aka samu a cikin wasu nau'in, ciki har da fiye da 30 bulges da aka adana a cikin wasu eukaryotes (Fig. 4a).Wannan hasarar tana kawar da lambobi da yawa tsakanin ribosomal subunits da maƙwabtan rRNA helices, wani lokaci yana haifar da manyan ɓatanci a cikin ribosome, yana sa E. cuniculi ribosome ya fi ƙura idan aka kwatanta da ribosomes na gargajiya (Fig. 4b).Musamman ma, mun gano cewa yawancin waɗannan ƙullun an kuma rasa su a cikin tsarin V. necatrix da P. locustae ribosome da aka gano a baya, waɗanda aka yi watsi da su ta hanyar nazarin tsarin da suka gabata31,32.
Wani lokaci hasarar ɓarkewar rRNA yana tare da haɓaka sabbin kumbura kusa da ɓarnar da aka rasa.Alal misali, ribosomal P-stem yana dauke da U1208 bulge (a cikin Saccharomyces cerevisiae) wanda ya tsira daga E. coli zuwa mutane kuma an kiyasta ya kasance shekaru biliyan 3.5.A lokacin haɗin sunadaran sunadaran, wannan ƙumburi yana taimaka wa tushen P ya motsa tsakanin buɗaɗɗen buɗewa da rufaffiyar daidaituwa ta yadda ribosome zai iya ɗaukar abubuwan fassara kuma ya isar da su zuwa wurin aiki.A cikin E. cuniculi ribosomes, wannan kauri ba ya nan;duk da haka, wani sabon thickening (G883) located kawai a cikin uku tushe nau'i-nau'i zai iya taimaka wa maido da mafi kyau duka sassauci na P kara (Fig. 4c).
Bayananmu akan rRNA ba tare da kumbura sun nuna cewa ragewar rRNA baya iyakance ga asarar abubuwan rRNA akan saman ribosome ba, amma kuma yana iya haɗawa da tsakiya na ribosome, haifar da takamaiman lahani na ƙwayoyin cuta wanda ba a bayyana shi a cikin sel masu rai ba.ana lura da nau'in rayuwa.
Bayan yin ƙirar sunadaran ribosomal na canonical da rRNA, mun gano cewa abubuwan haɗin ribosomal na al'ada ba za su iya bayyana sassa uku na hoton cryo-EM ba.Biyu daga cikin waɗannan guntuwar ƙananan ƙwayoyin cuta ne masu girma (Fig. 5, Ƙarin Hoto 8).An yi sandwiched kashi na farko tsakanin sunadaran ribosomal uL15 da eL18 a cikin wani matsayi da aka saba shagaltar da shi ta hanyar C-terminus na eL18, wanda aka gajarta a cikin E. cuniculi.Ko da yake ba za mu iya tantance ainihin wannan kwayar halitta ba, girman da siffar wannan tsibiri mai yawa an bayyana shi da kyau ta kasancewar ƙwayoyin spermidine.Haɗin sa ga ribosome yana daidaitawa ta takamaiman maye gurbi na microsporidia a cikin sunadaran uL15 (Asp51 da Arg56), waɗanda ke da alama suna ƙara kusancin ribosome don wannan ƙananan ƙwayoyin cuta, yayin da suke ba da izinin uL15 don kunsa ƙaramin ƙwayar a cikin tsarin ribosomal.Karin bayani na 2).8, ƙarin bayanai 1, 2).
Hoton Cryo-EM yana nuna kasancewar nucleotides a waje da ribose da aka ɗaure zuwa E. cuniculi ribosome.A cikin E. cuniculi ribosome, wannan nucleotide yana mamaye wuri ɗaya da 25S rRNA A3186 nucleotide (Lambar Saccharomyces cerevisiae) a yawancin sauran ribosomes eukaryotic.b A cikin tsarin ribosomal na E. cuniculi, wannan nucleotide yana tsakanin sunadaran ribosomal uL9 da eL20, don haka yana daidaita hulɗar da ke tsakanin sunadaran biyu.cd eL20 binciken kiyayewa a tsakanin nau'in microsporidia.Bishiyar phylogenetic na nau'in Microsporidia (c) da jeri mai yawa na furotin eL20 (d) sun nuna cewa ragowar Nucleotide-daure F170 da K172 ana kiyaye su a yawancin Microsporidia na yau da kullun, ban da S. lophii, ban da Microsporidia na farko, wanda ya riƙe ES.3.e Wannan adadi yana nuna cewa ragowar F170 da K172 suna cikin eL20 ne kawai na ƙananan ƙwayoyin microsporidia, amma ba a cikin sauran eukaryotes ba.Gabaɗaya, waɗannan bayanan suna ba da shawarar cewa ribosomes na Microsporidian sun haɓaka rukunin ɗaurin nucleotide wanda ya bayyana yana ɗaure ƙwayoyin AMP kuma yana amfani da su don daidaita hulɗar furotin-gina jiki a cikin tsarin ribosomal.Babban kiyaye wannan rukunin yanar gizon a cikin Microsporidia da rashinsa a cikin wasu eukaryotes yana nuna cewa wannan rukunin yanar gizon na iya ba da fa'idar rayuwa ga Microsporidia.Don haka, aljihun daurin nucleotide a cikin microsporidia ribosome ba ya bayyana a matsayin sifa mai lalacewa ko kuma ƙarshen nau'in lalata rRNA kamar yadda aka bayyana a baya, a'a, ƙirar juyin halitta mai amfani wanda ke ba microsporidia ribosome damar ɗaure ƙananan ƙwayoyin cuta kai tsaye, yana amfani da su azaman tubalan ginin kwayoyin halitta.tubalan gini don ribosomes.Wannan binciken ya sa microsporidia ribosome ya zama kawai ribosome da aka sani da amfani da nucleotide guda ɗaya a matsayin ginin gininsa.Hasashen hanyar juyin halitta da aka samo daga ɗaurin nucleotide.
Na biyu ƙananan nauyin nauyin kwayoyin halitta yana samuwa a tsaka-tsakin sunadaran ribosomal uL9 da eL30 (Fig. 5a).An yi bayanin wannan ƙirar a baya a cikin tsarin Saccharomyces cerevisiae ribosome azaman wurin ɗaure don 25S nucleotide na rRNA A3186 (ɓangare na ES39L rRNA tsawo)38.An nuna cewa a cikin degenerate P. locustae ES39L ribosomes, wannan haɗin gwiwar yana ɗaure wani nucleotide guda 31 wanda ba a san shi ba, kuma an ɗauka cewa wannan nucleotide shine rage nau'i na rRNA na ƙarshe, wanda tsawon rRNA ya kasance ~ 130-230 tushe.An rage ES39L zuwa nucleotide guda 32.43.Hotunan mu na cryo-EM suna goyan bayan ra'ayin cewa za a iya bayyana yawa ta hanyar nucleotides.Duk da haka, ƙuduri mafi girma na tsarin mu ya nuna cewa wannan nucleotide wani kwayoyin halitta ne na extraribosomal, mai yiwuwa AMP (Fig. 5a, b).
Sai muka tambayi ko wurin daurin nucleotide ya bayyana a cikin E. cuniculi ribosome ko kuma ya wanzu a baya.Tunda daurin nucleotide galibi ana yin sulhu ta hanyar ragowar Phe170 da Lys172 a cikin furotin na eL30 ribosomal, mun kimanta kiyaye waɗannan ragowar a cikin 4396 wakilin eukaryotes.Kamar yadda yake a cikin uL15 da ke sama, mun gano cewa ragowar Phe170 da Lys172 suna kiyayewa sosai kawai a cikin Microsporidia na al'ada, amma ba a cikin sauran eukaryotes, ciki har da microsporidia Mitosporidium da Amphiamblys, wanda ES39L rRNA guntu ba a rage 45.44, Fig.-e).
A hade, waɗannan bayanan suna goyan bayan ra'ayin cewa E. cuniculi da yuwuwar sauran microsporidia na canonical sun samo asali da kyau don kama adadi mai yawa na ƙananan metabolites a cikin tsarin ribosome don rama raguwar matakan rRNA da furotin.A yin haka, sun ɓullo da wata keɓantaccen iyawa don ɗaure nucleotides a wajen ribosome, suna nuna cewa sifofin ƙwayoyin cuta na parasitic suna ramawa ta hanyar ɗaukar ɗimbin ƙananan metabolites da amfani da su azaman tsarin kwaikwayo na ɓarna RNA da gutsuttsuran furotin..
Sashi na uku mara kwaikwaya na taswirar mu na cryo-EM, wanda aka samo a cikin babban subunit ribosomal.Matsakaicin babban ƙuduri (2.6 Å) na taswirar mu yana nuna cewa wannan ƙima na sunadaran sunadaran da ke da alaƙa na musamman na ragowar sarƙoƙi na gefe, wanda ya ba mu damar gano wannan ƙima a matsayin furotin ribosomal wanda ba a san shi ba wanda muka gano da suna msL2 (Microsporidia- takamaiman furotin L2) (hanyoyi, adadi 6).Binciken mu na homology ya nuna cewa an adana msL2 a cikin Microsporidia clade na halittar Encephaliter da Orosporidium, amma babu shi a cikin wasu nau'ikan, gami da sauran Microsporidia.A cikin tsarin ribosomal, msL2 ya ƙunshi rata da aka samu ta hanyar asarar tsawaita ES31L rRNA.A cikin wannan fanko, msL2 yana taimakawa daidaita rRNA nadawa kuma zai iya rama asarar ES31L (Hoto 6).
Ƙaƙƙarfan Electron da samfur na ƙayyadaddun furotin ribosomal na Microsporidia msL2 da aka samu a cikin E. cuniculi ribosomes.Yawancin ribosomes na eukaryotic, ciki har da 80S ribosome na Saccharomyces cerevisiae, suna da haɓakar ES19L rRNA da aka rasa a yawancin nau'in Microsporidian.Tsarin da aka kafa a baya na V. necatrix microsporidia ribosome yana nuna cewa asarar ES19L a cikin waɗannan parasites an biya su ta hanyar juyin halitta na sabon furotin na msL1 ribosomal.A cikin wannan binciken, mun gano cewa E. cuniculi ribosome kuma ya haɓaka ƙarin furotin na ribosomal RNA na mimic a matsayin ramuwa na fili don asarar ES19L.Duk da haka, msL2 (wanda aka kwatanta a halin yanzu azaman furotin ECU06_1135) da msL1 suna da mabambantan tsari da asalin juyin halitta.c Wannan binciken da aka yi na tsararrun sunadaran msL1 da msL2 da ba su da alaƙa da juyin halitta yana nuna cewa idan ribosomes sun tara maye gurbi a cikin rRNA ɗinsu, za su iya cimma matakan da ba a taɓa ganin irinsu ba na bambance-bambancen abun ciki ko da ƙaramin nau'in nau'ikan nau'ikan da ke da alaƙa.Wannan binciken zai iya taimakawa wajen fayyace asali da juyin halitta na mitochondrial ribosome, wanda aka san shi da raguwar rRNA sosai da kuma rashin daidaituwa a cikin abubuwan gina jiki a cikin nau'ikan nau'ikan.
Sa'an nan kuma muka kwatanta furotin msL2 tare da furotin msL1 da aka kwatanta a baya, kawai sanannun sunadarin microsporidia-takamaiman ribosomal da aka samu a cikin V. necatrix ribosome.Mun so mu gwada ko msL1 da msL2 suna da alaƙa da juyin halitta.Bincikenmu ya nuna cewa msL1 da msL2 sun mamaye rami ɗaya a cikin tsarin ribosomal, amma suna da tsarin firamare da na sakandare daban-daban, waɗanda ke nuna asalinsu na juyin halitta masu zaman kansu (Fig. 6).Don haka, binciken mu na msL2 yana ba da shaida cewa ƙungiyoyin ƙananan nau'in eukaryotic na iya samun kansu da kansu suna haifar da sunadaran sunadaran ribosomal don rama asarar gutsuttsuran rRNA.Wannan binciken sananne ne a cikin cewa mafi yawan ribosomes na cytoplasmic eukaryotic ribosomes sun ƙunshi furotin maras bambanci, gami da iyali ɗaya na sunadaran ribosomal 81.Bayyanar msL1 da msL2 a cikin nau'o'in microsporidia daban-daban don mayar da martani ga asarar daɗaɗɗen sassan rRNA yana nuna cewa lalacewar gine-ginen kwayoyin halitta na parasites yana sa ƙwayoyin cuta su nemi maye gurbin ramuwa, wanda zai iya haifar da samun su a cikin nau'o'in parasites daban-daban.Tsarin.
A ƙarshe, lokacin da samfurin mu ya ƙare, mun kwatanta abun da ke cikin E. cuniculi ribosome da wanda aka annabta daga jerin kwayoyin halitta.Yawancin sunadaran ribosomal, ciki har da eL14, eL38, eL41, da eS30, an riga an yi tunanin bacewar su daga E. cuniculi genome saboda bayyanar da rashi na homologues daga E. cuniculi genome.Asarar sunadaran ribosomal da yawa ana kuma annabta a cikin mafi yawan sauran ƙananan ƙwayoyin cuta na cikin salula da endosymbionts.Misali, ko da yake yawancin kwayoyin cuta masu rai suna dauke da iyali guda na sunadaran sunadaran ribosomal guda 54, 11 ne kawai daga cikin wadannan iyalai masu gina jiki ke da nau'in homologues a cikin kowane nau'in kwayar halitta da aka tantance na ƙwayoyin cuta.Don goyan bayan wannan ra'ayi, an yi gwajin hasarar sunadaran ribosomal a cikin V. necatrix da P. locustae microsporidia, waɗanda basu da eL38 da eL4131,32 sunadaran.
Koyaya, tsarin mu ya nuna cewa eL38, eL41, da eS30 ne kawai aka ɓace a cikin E. cuniculi ribosome.An adana furotin na eL14 kuma tsarinmu ya nuna dalilin da yasa ba a iya samun wannan furotin a cikin binciken homology (Fig. 7).A cikin E. cuniculi ribosomes, yawancin wuraren daurin eL14 sun ɓace saboda lalacewa na ES39L mai haɓakar rRNA.Idan babu ES39L, eL14 ya rasa yawancin tsarinsa na biyu, kuma kawai 18% na jerin eL14 ya kasance iri ɗaya a cikin E. cuniculi da S. cerevisiae.Wannan tsari mara kyau yana da ban mamaki saboda hatta Saccharomyces cerevisiae da Homo sapiens-kwayoyin da suka samo asali na shekaru biliyan 1.5 baya-raba fiye da kashi 51% na sauran ragowar a cikin eL14.Wannan mummunar asarar kiyayewa ta bayyana dalilin da yasa E. cuniculi eL14 a halin yanzu ana bayanin shi azaman furotin M970_061160 wanda ba a matsayin furotin na eL1427 ba.
da Microsporidia ribosome ya rasa ES39L rRNA tsawo, wanda ya kawar da wani bangare na eL14 ribosomal rukunin daurin furotin.Idan babu ES39L, furotin na eL14 microspore yana fuskantar asarar tsarin na biyu, wanda tsohon rRNA-daure α-helix ya lalata cikin madauki kaɗan.b Daidaita jeri da yawa yana nuna cewa furotin eL14 yana da matuƙar kiyayewa a cikin nau'in eukaryotic (57% jerin sunayen tsakanin yisti da homologues na ɗan adam), amma rashin kiyayewa da rarrabuwa a cikin microsporidia (wanda babu fiye da 24% na ragowar sun kasance daidai da eL14 homologue).daga S. cerevisiae ko H. sapiens).Wannan mummunan tsarin kiyayewa da bambancin tsarin na biyu ya bayyana dalilin da ya sa ba a taɓa samun eL14 homologue a cikin E. cuniculi da kuma dalilin da yasa ake tunanin wannan furotin ya ɓace a cikin E. cuniculi.Sabanin haka, E. cuniculi eL14 an riga an bayyana shi azaman furotin M970_061160 mai sakawa.Wannan abin lura yana nuna cewa a halin yanzu ana ƙididdige bambancin ƙwayoyin halittar microsporidia: wasu kwayoyin halittar da ake tunanin za su ɓace a cikin microsporidia a zahiri ana kiyaye su, kodayake a cikin nau'ikan bambance-bambancen;a maimakon haka, wasu ana tunanin su yi code don microsporidia genes don takamaiman sunadaran tsutsotsi (misali, furotin da ake tsammani M970_061160) a zahiri lambobin sunadaran sunadaran da aka samu a cikin sauran eukaryotes.
Wannan binciken yana nuna cewa denaturation na rRNA na iya haifar da hasara mai ban mamaki na kiyayewa a cikin sunadaran ribosomal kusa da su, yana mai da waɗannan sunadaran ba a iya gano su don binciken homology.Don haka, za mu iya wuce gona da iri na ainihin matakin lalacewar ƙwayoyin cuta a cikin ƙananan kwayoyin halitta, tun da wasu sunadaran da ake zaton sun ɓace a zahiri sun dawwama, duk da cewa sun sami canji sosai.
Ta yaya parasites za su iya riƙe aikin injinan kwayoyin su a ƙarƙashin yanayin matsanancin raguwar kwayoyin halitta?Bincikenmu ya amsa wannan tambayar ta hanyar kwatanta hadadden tsarin kwayoyin halitta (ribosome) na E. cuniculi, kwayar halitta mai daya daga cikin mafi kankantar kwayoyin halittar eukaryotic.
An san kusan shekaru ashirin da suka gabata cewa furotin da kwayoyin RNA a cikin ƙwayoyin cuta na ƙwayoyin cuta sau da yawa sun bambanta da kwayoyin halitta masu kama da juna a cikin nau'in rayuwa masu 'yanci saboda ba su da cibiyoyin kula da inganci, an rage su zuwa 50% na girman su a cikin kwayoyin halitta masu rai, da dai sauransu.yawancin maye gurbi masu raɗaɗi waɗanda ke cutar da naɗewa da aiki.Alal misali, ribosomes na kananan kwayoyin halitta, ciki har da yawancin parasites na intracellular da endosymbionts, ana sa ran ba za su rasa sunadaran ribosomal da yawa da kuma kashi ɗaya bisa uku na nucleotides na rRNA idan aka kwatanta da nau'in masu rai masu rai 27, 29, 30, 49. Duk da haka, hanyar da wadannan kwayoyin ke aiki a cikin kwayoyin halitta, sun kasance mafi girma ta hanyar ƙwayoyin cuta.
Bincikenmu ya nuna cewa tsarin macromolecules zai iya bayyana abubuwa da yawa na juyin halitta waɗanda ke da wuyar cirewa daga nazarin kwatancen al'ada na al'ada na ƙwayoyin cuta na cikin salula da sauran ƙwayoyin cuta masu ƙuntatawa (Ƙarin Hoto 7).Misali, misali na furotin eL14 ya nuna cewa za mu iya wuce gona da iri na ainihin matakin lalata na'urorin kwayoyin halitta a cikin nau'in parasitic.An yi imanin cewa ƙwayoyin cuta na encephalitic yanzu suna da ɗaruruwan ƙayyadaddun ƙwayoyin microsporidia.Duk da haka, sakamakonmu ya nuna cewa wasu daga cikin waɗannan da ake ganin ƙayyadaddun kwayoyin halitta a haƙiƙa ne kawai bambance-bambancen jinsin halittu waɗanda suka zama ruwan dare a cikin wasu eukaryotes.Bugu da ƙari, misalin furotin na msL2 yana nuna yadda muke yin watsi da sababbin sunadaran ribosomal kuma muna raina abubuwan da ke cikin injunan ƙwayoyin cuta.Misalin ƙananan kwayoyin halitta yana nuna yadda za mu iya yin watsi da mafi kyawun sabbin abubuwa a cikin sifofin kwayoyin halitta waɗanda za su iya ba su sabon ayyukan nazarin halittu.
A hade, waɗannan sakamakon sun inganta fahimtarmu game da bambance-bambance tsakanin tsarin kwayoyin halitta na ƙwayoyin cuta masu ƙuntatawa da takwarorinsu a cikin halittu masu rai.Mun nuna cewa injunan ƙwayoyin cuta, waɗanda aka daɗe ana tunanin za a rage su, sun lalace, kuma suna ƙarƙashin maye gurbi iri-iri masu rauni, a maimakon haka suna da sawun fasali na tsarin da ba a saba mantawa da su ba.
A gefe guda kuma, ɓangarorin rRNA da ba su da girma da gutsuttsuran da muka samu a cikin ribosomes na E. cuniculi sun ba da shawarar cewa rage genome zai iya canza ko da waɗancan sassan na kayan aikin kwayoyin halitta waɗanda aka kiyaye su a cikin sassa uku na rayuwa - bayan kusan shekaru biliyan 3.5.juyin halitta mai zaman kanta na nau'in.
Rubutun rRNA marasa kumbura da fused a cikin E. cuniculi ribosomes suna da sha'awa ta musamman ga hasken binciken da suka gabata na kwayoyin RNA a cikin kwayoyin endosymbiotic.Misali, a cikin aphid endosymbiont Buchnera aphidicola, kwayoyin rRNA da tRNA an nuna suna da sifofi masu yawan zafin jiki saboda son rai na abun da ke ciki na A+T da kuma babban kaso na tushe nau'i-nau'i na canonical20,50.Wadannan canje-canje a cikin RNA, da kuma canje-canje a cikin kwayoyin sunadaran sunadaran, yanzu ana zaton suna da alhakin dogara ga endosymbionts akan abokan tarayya da kuma rashin iyawar endosymbionts don canja wurin zafi 21, 23.Ko da yake parasitic microsporidia rRNA yana da sauye-sauye daban-daban, yanayin waɗannan canje-canjen yana nuna cewa rage kwanciyar hankali da kuma dogaro ga sunadaran chaperone na iya zama fasalin gama-gari na ƙwayoyin RNA a cikin kwayoyin halitta tare da raguwar kwayoyin halitta.
A gefe guda, tsarin mu yana nuna cewa ƙwayoyin cuta na microsporidia sun samo asali na musamman don tsayayya da rRNA da gutsuttsuran furotin, suna haɓaka ikon yin amfani da ɗimbin yawa kuma ana samunsu da ƙananan metabolites azaman tsarin kwaikwayo na rRNA da gurɓataccen furotin.Rushewar tsarin kwayoyin halitta..Wannan ra'ayi yana goyan bayan gaskiyar cewa ƙananan ƙwayoyin cuta waɗanda ke rama asarar gutsuttsuran furotin a cikin rRNA da ribosomes na E. cuniculi suna ɗaure ga takamaiman ragowar microsporidia a cikin furotin uL15 da eL30.Wannan yana nuna cewa ɗaure ƙananan ƙwayoyin cuta zuwa ribosomes na iya zama samfur na zaɓi mai kyau, wanda aka zaɓa takamaiman maye gurbin microsporidia a cikin sunadaran ribosomal don ikon su na ƙara kusancin ribosomes ga ƙananan ƙwayoyin cuta, wanda zai iya haifar da mafi kyawun kwayoyin ribosomal.Binciken ya bayyana ingantaccen sabon abu a cikin tsarin ƙwayoyin cuta na ƙwayoyin cuta na ƙwayoyin cuta kuma yana ba mu kyakkyawar fahimtar yadda tsarin ƙwayoyin ƙwayoyin cuta ke kula da aikinsu duk da haɓakar juyin halitta.
A halin yanzu, ba a san gano waɗannan ƙananan ƙwayoyin cuta ba.Ba a bayyana dalilin da ya sa bayyanar waɗannan ƙananan ƙwayoyin cuta a cikin tsarin ribosomal ya bambanta tsakanin nau'in microsporidia ba.Musamman ma, ba a bayyana dalilin da yasa aka lura da ɗaurin nucleotide a cikin ribosomes na E. cuniculi da P. locustae, kuma ba a cikin ribosomes na V. necatrix ba, duk da kasancewar ragowar F170 a cikin eL20 da K172 sunadaran V. necatrix.Ana iya haifar da wannan gogewa ta hanyar ragowar 43 uL6 (wanda yake kusa da aljihun ɗaurin nucleotide), wanda shine tyrosine a cikin V. necatrix kuma ba threonine a cikin E. cuniculi da P. locustae.Babban sarkar gefen aromatic na Tyr43 na iya tsoma baki tare da ɗaurin nucleotide saboda haɗe-haɗe.A madadin, bayyananniyar gogewar nucleotide na iya kasancewa saboda ƙarancin ƙuduri na hoton cryo-EM, wanda ke hana yin ƙirar ƙirar V. necatrix ribosomal gutsuttsura.
A gefe guda kuma, aikinmu yana nuna cewa tsarin lalata kwayoyin halitta na iya zama ƙarfin ƙirƙira.Musamman ma, tsarin E. cuniculi ribosome yana nuna cewa asarar rRNA da gutsutsayen furotin a cikin microsporidia ribosome yana haifar da matsa lamba na juyin halitta wanda ke inganta canje-canje a cikin tsarin ribosome.Waɗannan bambance-bambancen suna faruwa nesa da wurin aiki na ribosome kuma suna bayyana suna taimakawa kiyaye (ko maidowa) madaidaicin taron ribosome wanda in ba haka ba zai rushe ta hanyar rage rRNA.Wannan yana nuna cewa babban ƙirƙira na microsporidia ribosome ya bayyana ya samo asali ne zuwa buƙatun da za a iya ƙwace ɗigon halitta.
Wataƙila wannan shine mafi kyawun kwatanta ta hanyar ɗaurin nucleotide, wanda ba a taɓa ganin shi a cikin sauran halittu ba ya zuwa yanzu.Kasancewar ragowar abubuwan da ke ɗaure nucleotide suna nan a cikin microsporidia na yau da kullun, amma ba a cikin sauran eukaryotes ba, yana nuna cewa wuraren da ke ɗaure nucleotide ba kawai abubuwan da ke jira ba ne, ko kuma wurin ƙarshe na rRNA da za a maido da su zuwa nau'in nucleotides guda ɗaya.Madadin haka, wannan rukunin yanar gizon yana kama da fasali mai fa'ida wanda zai iya samo asali akan zagaye da dama na ingantaccen zaɓi.Shafukan daurin Nucleotide na iya zama samfur na zaɓi na halitta: da zarar ES39L ya ƙasƙanta, ana tilasta microsporidia don neman diyya don dawo da mafi kyawun ribosome biogenesis a cikin rashin ES39L.Tun da wannan nucleotide na iya yin kwaikwayi lambobin kwayoyin A3186 nucleotide a cikin ES39L, kwayoyin nucleotide ya zama tubalin ginin ribosome, daurin da aka kara inganta ta hanyar maye gurbin jerin eL30.
Dangane da juyin halittar kwayoyin halittar kwayoyin cuta na cikin salula, bincikenmu ya nuna cewa karfin zabin yanayi na Darwiniyanci da rugujewar kwayoyin halitta ba sa aiki a layi daya, sai dai yawo.Na farko, hawan jini yana kawar da muhimman fasalulluka na kwayoyin halitta, yana yin diyya da ake buƙata sosai.Sai kawai lokacin da parasites suka gamsar da wannan buƙatu ta hanyar zaɓin yanayi na Darwiniyanci ne macromolecules ɗin su za su sami damar haɓaka halayensu masu ban sha'awa da sabbin abubuwa.Mahimmanci, juyin halittar nucleotide da ke daure a cikin E. cuniculi ribosome yana nuna cewa wannan hasara-zuwa-riba tsarin juyin halittar kwayoyin halitta ba wai kawai yana kawar da maye gurbi ba, amma wani lokacin yana ba da sabbin ayyuka gaba daya akan macromolecules na parasitic.
Wannan ra'ayin ya yi daidai da ka'idar ma'auni mai motsi na Sewell Wright, wanda ya bayyana cewa tsauraran tsarin zaɓin yanayi yana iyakance ikon kwayoyin halitta don haɓaka51,52,53.Duk da haka, idan ɗigon kwayoyin halitta ya rushe zaɓin yanayi, waɗannan ɗigogi na iya haifar da canje-canje waɗanda ba su dace da kansu ba (ko ma da lahani) amma suna haifar da ƙarin canje-canje waɗanda ke ba da mafi girman dacewa ko sabon aikin ilimin halitta.Tsarin mu yana goyan bayan wannan ra'ayin ta hanyar nuna cewa nau'in maye gurbi iri ɗaya wanda ke rage ninki da aikin kwayar halitta ya bayyana shine babban abin da ke haifar da haɓakarsa.Dangane da tsarin juyin halitta na nasara-nasara, bincikenmu ya nuna cewa lalatawar kwayoyin halitta, wanda a al'adance ake kallonsa azaman tsari mai lalacewa, shi ma babban direban kirkire-kirkire ne, wani lokaci kuma watakila ma sau da yawa yana barin macromolecules su sami sabbin ayyuka na parasitic.iya amfani da su.