Taolo ea Tlhahiso ea Liphatsa tsa Lefutso Linthong tse Phelang
Taolo ea tlhahiso ea liphatsa tsa lefutso ke mokhoa oa ho laola hore na liphatsa tsa lefutso li buloa kapa li tima ka har'a sele neng, hokae, le hore na li buloa hakae ka har'a sele. Le hoja hoo e batlang e le lisele tsohle tse phelang tse nang le lisele tse ngata li arolelana DNA e tšoanang, mofuta o mong le o mong oa sele o ka ba le mesebetsi e fapaneng—mohlala, lisele tsa methapo, lisele tsa mesifa le lisele tsa sebete. Liphapang tsena li hlaha ka lebaka la tlhahiso ea liphatsa tsa lefutso e khethiloeng: ke liphatsa tsa lefutso tse itseng feela tse sebetsang ka linako tse itseng le tlas'a maemo a itseng. Taolo ea tlhahiso ea liphatsa tsa lefutso ke motheo oa bohlokoa bakeng sa nts'etsopele ea lesea le sa tsoa emoloa, phapang ea lisele, likarabo tsa tikoloho, le ho boloka botsitso ba 'mele (homeostasis). Ho sitisoa ha molao ona ho ka baka mafu a fapaneng, ho kenyeletsoa kankere, mathata a metabolism le mathata a nts'etsopele.
Mehopolo ea motheo: ho tloha liphatseng tsa lefutso ho ea liprotheineng
Hangata polelo ea liphatsa tsa lefutso e bolela phallo ea tlhahisoleseling ea baeloji ho tloha ho DNA ho ea ho RNA ebe e ea ho protheine (molao-motheo o ka sehloohong oa baeloji ea limolek'hule). Leha ho le joalo, polelo ea liphatsa tsa lefutso ha e felle feela tlhahisong ea protheine: liphatsa tse ling tsa lefutso li hlahisa li-RNA tse sebetsang (mohlala, rRNA, tRNA, kapa microRNA) tse sebetsang ka kotloloho ntle le ho fetoleloa ho ba protheine. Hobane lihlahisoa tsa liphatsa tsa lefutso - liprotheine kapa RNA - li khetholla sebopeho le ts'ebetso ea sele, lintho tse phelang li hloka sistimi e nepahetseng ea taolo bakeng sa tlhahiso ea liphatsa tsa lefutso e sebetsang hantle, e shebaneng le eona, le e loketseng.
Ka kakaretso, taolo ea tlhahiso ea liphatsa tsa lefutso e ka etsahala maemong a 'maloa: (1) taolo ea epigenetic le sebopeho sa chromatin, (2) taolo ea transcriptional, (3) ts'ebetso ea RNA ea kamora ho ngoloa, (4) botsitso le lipalangoang tsa RNA, (5) taolo ea phetolelo, le (6) phetoho le ho senyeha ha protheine. Boemo bo bong le bo bong bo fana ka "lintlha tsa taolo" tseo sele e ka li sebelisang ho laola tlhahiso ea ho qetela.
Taolo ea Epigenetic: e laolang phihlello ea DNA
Lera la pele la taolo ke epigenetics, e leng diphetoho tse amang tshebetso ya jini ntle le ho fetola tatellano ya motheo wa DNA. Mekgwa e meholo ya epigenetic e kenyeletsa methylation ya DNA, phetoho ya histone, le taolo ya sebopeho sa chromatin.
Methylation ea DNA hangata e hlaha ho li-cytosine libakeng tsa CpG 'me hangata e amahanngoa le ho hatelloa ha tlhahiso ea liphatsa tsa lefutso. Ha promoter e na le methylated, lintlha tsa transcription li ba thata le ho feta ho li kopanya, e leng se fellang ka ho fokotseha ha phetolelo. Ka lehlakoreng le leng, demethylation e ka bula monyako oa ts'ebetso ea liphatsa tsa lefutso. Liphetoho tsa Histone—tse kang acetylation le methylation ea mehatla ea histone—li fetola bongata ba chromatin. Acetylation ea Histone e atisa ho "lokolla" chromatin (euchromatin), e leng se etsang hore phetolelo ea liphatsa tsa lefutso e be bonolo, ha mefuta e meng ea methylation ea histone e ka kopanya chromatin (heterochromatin) le ho thibela tlhahiso.
Taolo ea epigenetic e bohlokoa bakeng sa phapang ea lisele. Mohlala, nakong ea kholo ea lesea le sa tsoa emoloa, qalong lisele tse tšoanang li "notlela" mekhoa e itseng ea tlhahiso ea liphatsa tsa lefutso ka matšoao a epigenetic, ka hona li boloka boitsebiso ba sele ha lisele li ntse li arohana. Mabaka a tikoloho a kang phepo e nepahetseng, khatello ea maikutlo le ho pepesehela lik'hemik'hale le 'ona a ka susumetsa epigenome, a hlalosa hore na ke hobane'ng ha mabaka a kantle a ka fetola tlhahiso ea liphatsa tsa lefutso ka nako e telele.
Taolo ea phetolelo: karolo ea batšehetsi, ba ntlafatsang, le lintlha tsa phetolelo
Boemo ba taolo bo ithutoang haholo ke taolo ea mongolo, e leng taolo ea ts'ebetso ea ho thehoa ha RNA ho tsoa ho DNA ka RNA polymerase. Ho li-eukaryote, mongolo hangata o qala ho promoter, tatellano ea DNA moo motsoako oa mongolo o thehoang teng. Ntle le promoter, ho na le li-enhancer le li-silencer—likarolo tse laolang tse ka eketsang kapa tsa fokotsa sekhahla sa mongolo, esita le ha li le hole le gene e laoloang. DNA e ka mena ka li-loops, e lumellang li-enhancer ho sebelisana le promoter ka liprotheine tsa linker.
Lintho tse etsang hore DNA e ngoloe ke liprotheine tse tlamang tatellano e itseng ea DNA le ho laola ts'ebetso ea RNA polymerase. Ho na le lintlha tse akaretsang tse hlokahalang ho qala ho ngoloa ha DNA liphatseng tse ngata tsa lefutso, le lintlha tse itseng tse etsang hore DNA e ngoloe liphatseng tsa lefutso tse sebetsang feela liphatseng kapa liseleng tse itseng tsa lefutso. Lintho tse ngata tse etsang hore mongolo o ngoloe li susumetsoa ke matšoao a sele, joalo ka lihormone, lintlha tsa kholo, kapa maemo a khatello ea maikutlo. Ha lets'oao le fihla, ntho e etsang hore mongolo o ngoloe e ka kenngoa tšebetsong ka phosphorylation, phetoho ea sebaka (mohlala, ho kena ka har'a nucleus), kapa tšebelisano le li-coactivator le li-co-repressors.
Libaktheria, taolo ea phetolelo hangata e hlalosoa ka mohopolo oa li-operons, joalo ka lac operon ho Escherichia coli. Ho lac operon, boteng ba lactose bo sitisa repressor, e leng se lumellang liphatsa tsa lefutso tse silang lactose ho ngoloa. Ho feta moo, ho fumaneha ha tsoekere ho susumetsa protheine ea CAP-cAMP, e eketsang phetolelo ha tsoekere e le tlase. Mohlala ona o bontša hore taolo ea liphatsa tsa lefutso e ka kopanya matšoao a mangata a tikoloho ka nako e le 'ngoe.
Ts'ebetso ea RNA kamora ho ngoloa ha mongolo: ho kopanya le ho fapana ha sehlahisoa sa liphatsa tsa lefutso
Ho li-eukaryote, RNA e sa tsoa ngoloa (pre-mRNA) e tlameha ho sebetsoa pele e fetoha mRNA e butsoitseng. Ts'ebetso ena e kenyelletsa ho eketsoa ha sekoahelo sa 5', polyadenylation pheletsong ea 3' (mohatla oa poly-A), le ho kopanya ho tlosa li-intron le ho kopanya li-exons. Taolo mohatong ona e ka fetola mofuta oa protheine e hlahisoang ho tsoa jineng e le 'ngoe.
Mokhoa o mong oa bohlokoa ke ho kopanya ka mokhoa o mong, moo metsoako e fapaneng ea li-exon e kopantsoeng hammoho ho hlahisa li-isoform tse fapaneng tsa protheine. Ho kopanya ka mokhoa o mong ho lumella mefuta e mengata ea protheine ntle le ho eketsa palo ea liphatsa tsa lefutso. Taolo ea ho kopanya ka mokhoa o mong e laoloa ke liprotheine tse tlamang RNA le tatellano ea matšoao ho pre-mRNA. Mekhoa ea ho kopanya ka mokhoa o mong e ka fapana liseleng tse fapaneng, e lumellang jini e le 'ngoe ho hlahisa sehlahisoa se nang le mosebetsi o itseng bakeng sa lisele tseo.
Botsitso le ho tsamaisoa ha mRNA: ho laola "nako ea bophelo" ea melaetsa ea liphatsa tsa lefutso
Hang ha mRNA e seng e holile e se e thehiloe, lisele li ka laola hore na e tla nka nako e kae pele e senyeha. Ho tsitsa ha mRNA ho etsa qeto ea hore na ho ka hlahisoa protheine e kae ho eona. Libaka tse itseng tsa mRNA, haholo-holo sebaka sa 3' se sa fetoleloang (3' UTR), li na le likarolo tse tlamang liprotheine tse laolang kapa li-RNA tse nyane, tse amang ho senyeha le katleho ea phetolelo.
Ho phaella moo, mRNA e lokela ho isoa ho tloha khubung ho ya cytoplasm. Maemong a mang, mRNA e boetse e "lebiswa" libakeng tse itseng ka hara sele (mohlala, diseleng tsa methapo, ho di-dendrite kapa di-axon). Ho fumaneha ha mRNA sebakeng se itseng ho dumella tlhahiso ya protheine ho etsahala haufi le sebaka sa yona sa tshebetso, ho eketsa bokgoni le ho nepahala ha dikarabelo tsa sele.
Tšitiso ea RNA le RNA e sa ngoleng khoutu
Hase taolo yohle ya tlhahiso ya dijini e itshetlehileng hodima diprotheine. Di-RNA tse sa ngoleng khoutu, tse kang di-microRNA (di-miRNA) le di-RNA tse nyane tse sitisang (di-siRNA), ke balaodi ba bohlokwa dibopuweng tse ngata. di-miRNA di ka tlama ho shebana le di-mRNA mme tsa thibela phetolelo kapa tsa potlakisa ho senyeha ha tsona. Mokgwa ona, o tsejwang e le ho sitisa di-RNA (di-RNAi), o bapala karolo taolong ya ntshetsopele, tshireletso kgahlanong le dikokwana-hloko le botsitso ba genome.
Li-RNA tse ling tse sa ngoleng khoutu, tse kang li-RNA tse telele tse sa ngoleng khoutu (lncRNAs), li ka susumetsa tlhahiso ea liphatsa tsa lefutso ka litsela tse fapaneng—ho tloha ho tataisang metsoako ea phetoho ea chromatin ho ea libakeng tse itseng ho ea ho sebetsa joaloka "li-sponge" tse tlamang li-miRNA hore li se ke tsa thibela li-mRNA tse reretsoeng.
Taolo ea phetolelo le ea kamora phetolelo: taolo boemong ba protheine
Esita le ha mRNA e fumaneha, lisele li ntse li ka laola hore na e fetoleloa protheineng. Taolo ea phetolelo e bohlokoa ha lisele li hloka karabelo e potlakileng, joalo ka tlas'a khatello ea maikutlo. Lintho tse qalang phetolelo li ka kengoa tšebetsong kapa tsa thibeloa, tsa eketsa kapa tsa fokotsa tlhahiso ea liprotheine tse itseng.
Kamora hore protheine e etsoe, taolo ea kamora phetolelo e tsoela pele, ho kenyeletsoa le ho mena, ho arohana, ho eketsoa ha lihlopha tsa lik'hemik'hale (tse kang phosphorylation, glycosylation, ubiquitination), le taolo ea sebaka sa eona ka har'a sele. Ubiquitination hangata e tšoaea liprotheine bakeng sa timetso ke proteasome. Ka tsela ena, lisele li ka laola maemo a protheine ka thata, tsa tlosa liprotheine tse senyehileng, kapa tsa emisa kapele lipontšo.
Ho kopanngoa ha matšoao le bohlokoa ba taolo ea tlhahiso ea liphatsa tsa lefutso
Libopuong, mekhahlelo eohle e kaholimo ea taolo e sebetsa ka mokhoa o kopaneng. Mohlala, lihormone tsa steroid li ka kena liseleng 'me tsa tlama ho li-receptor tse sebetsang e le lintlha tsa transcription. Li-receptor tsena ebe li hira li-coactivator tse fetolang li-histone ho bula chromatin, e leng se ntlafatsang transcription ea liphatsa tsa lefutso tse reretsoeng. MRNA e hlahisoang e ka 'na ea feta ho kopanngoa ho hong ho latela mofuta oa sele, ebe e fetoleloa ka katleho e fapaneng ho latela maemo a metabolism.
Taolo ea tlhahiso ea liphatsa tsa lefutso le eona ke ea bohlokoa bakeng sa ho ikamahanya le tikoloho ea tsona ha lintho tse phelang. Likokoana-hlokong tse nyenyane, liphetoho tlhahisong ea liphatsa tsa lefutso li li lumella ho phela liphetoho tsa mocheso, pH, kapa ho fumaneha ha limatlafatsi. Limeleng, taolo ea liphatsa tsa lefutso e thusa ho arabela komello, letsoai le tlhaselo ea likokoana-hloko. Liphoofolong, sesole sa 'mele se itšetlehile ka taolo ea tlhahiso ea liphatsa tsa lefutso ho kenya tšebetsong liphatsa tsa lefutso bakeng sa li-cytokine, li-antibodies le limolek'hule tse ling tsa tšireletso ka mokhoa o potlakileng empa o laoloang.
Ho koala
Taolo ea tlhahiso ea liphatsa tsa lefutso linthong tse phelang ke sistimi e rarahaneng e lumellang genome e le 'ngoe ho hlahisa mefuta e fapaneng ea lisele le likarabo tsa 'mele. Ka ho laola phihlello ea DNA, ho laola phetolelo, ho fetola le ho khetha RNA, ho laola phetolelo, le ho fumana qetello ea liprotheine, lisele li khona ho ikamahanya le litlhoko tsa ka hare le liphetoho tsa tikoloho. Ho utloisisa taolo ea tlhahiso ea liphatsa tsa lefutso ha ho bohlokoa feela bakeng sa baeloji ea motheo empa hape ho rala motheo oa nts'etsopele ea mekhoa ea phekolo ea sejoale-joale joalo ka meriana e thehiloeng ho epigenetic, phekolo ea liphatsa tsa lefutso, le mekhoa e thehiloeng ho RNA. Ha mahlale a genomics le baeloji ea litsamaiso a ntse a tsoela pele, lipatlisiso mabapi le taolo ea tlhahiso ea liphatsa tsa lefutso li tla senola haholoanyane temohisiso mabapi le kamoo lintho tse phelang li hōlang, li ikamahanyang le ho boloka bophelo ba tsona bo botle.
