Ani inodzidza ezvinhu zvipenyu, nemakemikari omuviri, kuvabereki engineering, uye zvimwe ruzivo akarondedzera, pakupedzisira, anobvunza mubvunzo: chii mashandiro RNA polymerase? Uyu kumbonyanya kunzwisisa nyaya ichiri chose unexplored, asi, zvakadaro, zvinozivikanwa kuti uchavhenekerwa sechikamu nyaya.
Vhuṱanzi
Zvakakodzera kuyeuka kuti pane RNA polymerase pamusoro eukaryotes uye prokaryotes. Chokutanga zvatowedzera rakakamurwa mhando nhatu, mumwe nomumwe iri anokonzera transcription majini yoga boka. makemikari aya kuverengwa nyore, seyokutanga, wechipiri newechitatu RNA polymerase. Prokaryotes, maumbirwo izvo zvisiri zvenyukireya, kana transcribed anoshanda maererano kwainoita chati. Naizvozvo, nokuti yakajeka, kuti andobata mashoko yakawanda sezvingabvira vachange kubatwa eukaryotes. RNA polymerases vari zvayakaita zvakafanana. Zvinofungidzirwa kuti dzine kwete asingasviki 10 polypeptide ngetani. Saka RNA polymerase synthesizes 1 (transcribes) majini ayo dzakwidzwa kushandurirwa kupinda siyana mapurotini. Wechipiri avimbiswa transcribing majini, izvo vakabva kushandurirwa mapurotini. RNA polymerase 3 inoratidza siyana kugadzikana pasi samolecular uremu makemikari zviri zvine mwero nehanya Alpha amatinu. Asi isu hatina akasarudza chii chaizvoizvo RNA polymerase! Saka akadana makemikari zviri mubasa kwetunhu ribonucleic asidhi mamorekuru. In yakamanikana Mupfungwa kunzwisiswa ichi DNA-zvaanoda RNA polymerase, izvo anoshanda maererano chizvaro pakati deoxyribonucleic acid. Makemikari zvinokosha refu uye vabudirire kushanda zvipenyu. RNA polymerase anogona kuwanikwa masero ose uye mavhairasi akawanda.
Weboka riri chaizvo
Zvichienderana subunit Zvinoumba RNA polymerases vari mapoka mapoka maviri:
- The zveefa wekutanga transcribing vashoma majini vari genomes nyore. Nokuti oparesheni iyi nyaya hakurevi yakaoma pamutemo zvazvinoita. Naizvozvo, pano anoreva makemikari zvose kuti ine subunit mumwe chete. Somuenzaniso unogona kufurira bacteriophage RNA polymerase uye mitochondria.
- boka iri rinosanganisira zvose eukaryotic RNA polymerase uye utachiona, izvo zvakaoma akaronga. Vane oma mnogosubedinichnye mapuroteni zvivako anogona transcribe zviuru majini siyana. Panguva oparesheni, majini izvi sei vakawanda pamutemo anonongedzera kuti kubva mapuroteni zvinhu uye nucleotides.
STRUCTURAL uye dzichipfekeka kupesana kwakadaro nani zvimiso uye anoitwa mamiriro chaiwo.
Ko RNA polymerase I?
Vakanga wakaiswa kushanda dzidzo chinonyanya manotsi ose rRNA majini, kureva kuti zvinokosha. Ekupedzisira vanonyanya kuzivikanwa pasi pakunzi 45S-RNA. kureba yavo vanenge 13 000 nucleotides. Kubva vanonzi vakaumba 28S-RNA, 18S-5.8S RNA-RNA. Nokuti kuti Zvasikwa chete transkriptor mumwe, muviri anogamuchira "vimbiso" kuti mamorekuru chichagadzirirwa zvienzane zvizhinji. Panguva iyoyowo kwezvisikwa RNA zvakananga unoenda nucleotides 7000 chete. The vamwe inopangidza iri akafumuka mu mwoyo. On yakakura kudaro vakasara iri aidavira kuti zvakakodzera kuti tanga paumbwe ribosomes. Kuwanda polymerases aya masero dzakakwirira zvisikwa dzinodzengerera kumativi chiratidzo 40 zviuru dzakabatana.
Sei dzakarongeka?
Saka, tine yokutanga RNA polymerase (prokaryotes-mamiriro mamorekuru) anonzi akanaka. Panyaya iyi, hombe subunit, sezvo, zvirokwazvo, uye vazhinji mamwe matunhu samolecular uremu polypeptides, pane pachena distinguishable chadzo uye STRUCTURAL nzvimbo. Panguva cloning majini uye kuti vaone nechivako ravo chikuru vave kuzivikanwa nemasayendisiti evolutionarily migove conserved nengetani. Kushandisa zvakanaka mashoko, vaongorori vakanga kuitwawo mutational kuongorora kuti anotibvumira kuti titaure pamusoro dzichipfekeka kukosha nomumwe nzvimbo. Nokuti chinangwa ichi, achishandisa nzvimbo-akatungamirira mutagenesis kushandura munhu polypeptide ngetani, uye vakadaro dzakachinjwa amino asidhi subunits zvaishandiswa ungano makemikari vane unozotevera kuongorora zvivako, vakanga vawana munyika date zvivako. Yakati nokuda kwayo sangano wokutanga RNA polymerase pamberi Arifa-amatina (a zvikuru chepfu fuma, iyo akawana kubva toadstool rakachenuruka) hakurevi sei.
inoshanda
Vose rokutanga uye rechipiri RNA polymerase angawanika nenzira mbiri. Mumwe wavo anogona kuita kuti atange chaicho transcription. Wechipiri - a DNA-nemataundi RNA polymerase. Mafungiro aya ari wakaratidzwa kupfuura mudzimu basa. Subject adzidza zvakawanda, asi zvino tinoziva kuti zviri zviviri transcription zvinhu, izvo kunzi SL1 uye UBF pamusoro. Kunyanya zvapedzisira - kuti unogona kutaura zvakananga mutsigiri, ukuwo SL1 UBF kunoda kuvapo. Kunyange zvazvo zvave experimentally yakasimbiswa kuti DNA-zvaanoda RNA polymerase anogona mubasa transcription pane kushoma uye pasina kuvapo yokupedzisira. Asi nokuda chakaipa nokushanda kwenhengo mashandiro ichi UBF ichiri kudiwa. Sei zvakadaro? Sezvineiwo saka kure vakakundikana kumisa chikonzero maitiro ichi. Chimwe chezvinhu yakakurumbira tsananguro inoratidza kuti UBF Vatsigiri rinodhaka rDNA transcription imwe mhando apo iye inokura uye anovandudza. Kana nekuzorora danho kunoitika, ipapo akaramba shoma inodiwa nenhanho inoshanda. A chikamu transcription zvinhu hakukoshi kwaari. Pano saka anoita RNA polymerase. Mashandiro enzayemu ichi inobvumira kutsigira playback zviduku "Dzinovaka" muviri, nokuda icho kugara achiudza kwemakumi emakore.
Boka makemikari rechipiri
inoshanda yavo nokudzorwa paungano multiprotein kunzwisisa preinitsiatornogo vatsigiri mukirasi yechipiri. Kakawanda izvi runoratidzwa basa rinokosha mapurotini - activators. Somuenzaniso ndiyo TBP. Rinobatanidzwa zvinoita kuti vari chikamu TFIID. Ivo - atambudzwe p53, NF kappa B, uye zvichingodaro. simba rayo nedanho murau kupa mapurotini anonzi coactivators. Mienzaniso ndivo Gcn5. Sei tichida mapuroteni izvi? Vanoshanda sezvo adapters kuti gadzirisa nesungano pakati activators uye zvinoita kuti vari preinitsiatorny kunzwisisa. Kuti agadzirise transcription kwakaitika, unofanira kuva zvakafanira initiator zvinhu. Pasinei chokwadi kuti vatanhatu vavo pavanenge zvakananga mutsigiri chingava chete. Nokuti dzimwe nguva zvinoda preformed kunzwisisa chechipiri RNA polymerase. Uyezve, panguva pezvakaitwa ava pedyo proximal zvinhu - maviri kubva panzvimbo apo transcription iri rakatanga 50-200 chete. Ivo ane chiratidzo nokusungwa activator mapurotini.
zvinhu chaizvo zvechiratidzo
Ko subunit nemamiriro makemikari akasiyana mavambo avo dzichipfekeka basa transcription? Mhinduro chaiyo yomubvunzo uyu hapana, asi akatenda kuti zvichida zvakanaka. Sei zvinokanganisawo RNA polymerase? Enzayemu mabasa nyore maumbirwo - shoma zvakawanda transcription majini (kana kunyange chikamu chiduku). Mienzaniso ndiwo kwetunhu RNA primers Okazaki zvimedu. The nditsigire specificity pamusoro RNA polymerases utachiona uye phages ndechokuti makemikari vari yokuisira nyore marongerwo uye siyana. Izvi zvinogona kuonekwa muitiro DNA kuberekana mune utachiona. Kunyange zvazvo tinogona funga izvi: yakaoma chivako kana vadzidza genome T kunyange phage, panguva kukura, zvakanzi Zvakacherechedzwa kuti kudzokororwa nokuchinja pakati siyana mapoka Gene transcription, kwakaonekwa kuti zvakaoma rakashandiswa ichi RNA polymerase hondo. Kureva, imwe enzayemu nyore Muzviitiko zvakadaro hakuna vakafurira. Izvi zvinoreva dzinoverengeka nemigumisiro:
- RNA polymerase pamusoro eukaryotes uye mabhakitiriya vanofanira kugona vanosimudzira siyana.
- Zvakafanira kuti enzayemu ane yakananga mhinduro yakasiyana mapurotini-regulators.
- RNA polymerase anofanira kukwanisa kushandura kuziva specificity of template DNA nucleotide kutevedzana. Kuti aite izvi, kushandisa dzakasiyana-siyana mapuroteni effectors.
It anotevera muviri kudikanwa mamwe "chivakwa" zvinhu. Mapuroteni anobatsira transcribe zvakaoma RNA polymerase kuti zvizere aite mabasa ayo. Izvi zvinoshandawo, nokuti vakawanda, makemikari kunzwisisa mamiriro, umo yaibvira pakutevedzera chaizvo purogiramu magene mashoko. Nokuda matambudziko akasiyana-siyana, tinogona kuchengeta kuti akanyatsorongwa maumbirwo RNA polymerase imwe mhando.
pfungwa transcription sei?
Pane zviratidzo anokonzera nezvipatara pamwe RNA polymerase? Kutanga pamusoro transcription: mutoo mu eukaryotes kunoitika musimboti. In prokaryotes, inoyerera mukati microorganism. The ukama pakati polymerase chinhu chinokosha STRUCTURAL musimboti ane nopindirana kuberekesana nomumwe mamorekuru. On nhau nekuita anogona kutaura kuti DNA kungonamata template uye haachinji panguva transcription. Sezvo DNA iri RUBATSIRO RUNOTARISA enzayemu, chinhu ndechechokwadi, kuti imwe jini basa polymer ichi kunogona, asi richava refu chaizvo nguva. Hatifaniri kukanganwa kuti DNA rine mabhiriyoni 3.1 nucleotide residues. Saka, zvakawanda zvakakodzera kutaura kuti mumwe nomumwe mhando RNA paanosangana DNA kwayo. Nokuti unyatsoshanda polymerase kuita inoda simba uye ribonukle-ozidtrifosfato substrates. Kana paine zviri kuumbwa 3 ', 5'-phosphodiester zvisungo pakati ribonukleozidmonofosfatami. Morekuru RNA usage anotanga mamwe DNA sequences (vanosimudzira). The kwacho terminates panguva kugumiswa site (kugumiswa). Nzvimbo, iyo rinobatanidzwa pano anonzi transcriptional. In eukaryotes, panongova Gene imwe kazhinji, apo prokaryotes kunogonawo nhaka akawanda zvimedu remitemo. Mumwe transcriptional ane uninformative nharaunda. Ivo dziri dzakananga nucleotide sequences kuti anosangana transcriptional pamutemo zvinhu zvataurwa pamusoro apa.
Chirwere RNA polymerase
Izvi tusingaoneki imwe enzayemu ndiye anokonzera kwetunhu mRNA, rRNA uye tRNA. Paavhareji polymerase Morekuru ane nehasha 5 subunits. Vaviri ava vave kunyorerana nhengo enzayemu. Chimwe subunit munyaya mharuro kwetunhu. Panewo chezvinonhuwira kuti enzayemu nonspecific kuti kukurukura DNA. Uye yokupedzisira subunit yave kuunza RNA polymerase ari kushanda fomu. Zvinonzi kuzivikanwa kuti enzayemu mamorekuru havasi mu "yakasununguka" yokufambisa ari cytoplasm utachiona. Kana RNA polymerases anoshandiswa, ipapo kusunga non-chaicho DNA nharaunda uye vakamirira kusvikira yezviri nditsigire kuzarurwa. A zvishoma kutsauswa kubva wenyaya, zvinofanira kutaurwa kuti utachiona zviri nyore chaizvo kudzidza mapuroteni vavo simba pamusoro ribonucleic asidhi polymerase. Kunyanya nyore kwavari kuedza musi kurudziro kana chinovhiringidza wacho zvinhu. Nokuda kwavo yakakwirira kubereka mwero kunogona tichishandisa kukurumidza kuwana achida mugumisiro. Haiwa, muchidzidza dzevanhu hazvigoni kuitwa panguva yakadaro Kukurumidza nekuvongwa yedu kusiyana STRUCTURAL.
RNA polymerase "abatwa" mu-siyana?
Runouya inonzwisisika mhedziso nyaya. Huru ngwariro rwakabhadharwa kuna eukaryotes. Asi pachine archaea uye wanda. Saka unoda kurerekera nzeve uye mhando iyi youpenyu. The chinokosha basa Archean kunongova boka rimwe RNA polymerases. Asi chaizvo zvakafanana ehupfumi dzaro nhatu songaniro eukaryotes. Masayendisiti akawanda zvave zvichinzi zvatinogona kuona kubva Arche chaizvoizvo-shanduka tateguru specialized polymerases. Zvinofadza, uye nemamiriro wanda. Sezvo ambonyora, kwete vose zvipenyu izvi nokuzvidya polymerase kwavo. Uye apo iri, ndiko chete subunit. Zvinonzi vaidavira kuti nemavhairasi makemikari zvinobva DNA polymerases, panzvimbo kunzwisisa RNA zvivako. Kunyange nokuda kusiyana siyana Implementation paanoonanazve kupiwa chaivo mashandiro boka iri zvigare.
mhedziso
Haiwa, vanhu haasati ave mashoko vsoy zvakakodzera kunodiwa kuti kunzwisisa genome. Uye kuti iye chete ndiye aigona maita! Anenge zvirwere zvose zviri zvikurukuru chete majini hwaro - ichi rinoshanda kunyanya kune nemavhairasi kuti nguva dzose anotipa matambudziko zvirwere uye zvichingodaro. Kwazvo uye nehosha - vari zvakare, chokwadi, zvakananga kana zvisina kunanga kuvimba kwevanhu genome. Patinoziva kunzwisisa mavari uye achashanda ruzivo urwu kubatsira vakawanda matambudziko uye zvirwere zvichaita nyore tisisipo. Zvino chinhu chekare, zhinji zvirwere kare zvinotyisa zvakadai sechibhokisi, denda. Kugadzirira kuenda mumps, whooping chikosoro. Asi regai dzikama nokuti tatarisana yakakura zvinoverengeka zvakasiyana kuti unofanira kuwana mhinduro. Uye vachawanikwa, nekuti zviri kuenda kudaro.