Kev Tswj Xyuas Kev Qhia Txog Gene Hauv Cov Kab Mob
Kev tswj hwm kev qhia tawm ntawm cov noob caj noob ces yog tus txheej txheem ntawm kev tswj hwm thaum twg, qhov twg, thiab ntau npaum li cas ib qho noob caj noob ces raug qhib lossis kaw hauv ib lub cell. Txawm hais tias yuav luag txhua lub cell hauv ib lub cev muaj ntau lub cell sib koom tib yam DNA, txhua hom cell tuaj yeem muaj cov haujlwm sib txawv - piv txwv li, cov hlab ntsha, cov leeg nqaij, thiab cov hlwb siab. Cov kev sib txawv no tshwm sim vim yog kev xaiv cov noob caj noob ces: tsuas yog qee cov noob caj noob ces ua haujlwm rau qee lub sijhawm thiab nyob rau hauv qee qhov xwm txheej. Kev tswj hwm kev qhia tawm ntawm cov noob caj noob ces yog lub hauv paus tseem ceeb rau kev loj hlob ntawm cov menyuam hauv plab, kev sib txawv ntawm cov cell, cov lus teb ib puag ncig, thiab kev tswj hwm kev sib npaug ntawm lub cev (homeostasis). Kev cuam tshuam ntawm qhov kev tswj hwm no tuaj yeem ua rau muaj ntau yam kab mob, suav nrog mob qog noj ntshav, kev puas tsuaj ntawm cov metabolism, thiab kev loj hlob tsis zoo.
Cov ntsiab lus tseem ceeb: los ntawm cov noob caj noob ces mus rau cov protein
Feem ntau, kev qhia txog cov noob caj noob ces (gene expression) yog hais txog kev ntws ntawm cov ntaub ntawv txog kab mob los ntawm DNA mus rau RNA thiab tom qab ntawd mus rau protein (lub hauv paus ntsiab lus ntawm molecular biology). Txawm li cas los xij, kev qhia txog cov noob caj noob ces tsis txwv rau kev tsim cov protein: qee cov noob caj noob ces tsim cov RNA ua haujlwm (piv txwv li, rRNA, tRNA, lossis microRNA) uas ua haujlwm ncaj qha yam tsis tau txhais ua protein. Vim tias cov khoom ntawm cov noob caj noob ces - protein lossis RNA - txiav txim siab txog cov qauv thiab kev ua haujlwm ntawm lub cell, cov kab mob xav tau ib lub kaw lus tswj hwm kom meej rau kev qhia txog cov noob caj noob ces zoo, tsom mus rau, thiab tsim nyog.
Feem ntau, kev tswj hwm ntawm kev qhia tawm ntawm cov noob caj noob ces tuaj yeem tshwm sim ntawm ntau theem: (1) kev tswj hwm epigenetic thiab cov qauv chromatin, (2) kev tswj hwm transcriptional, (3) kev ua RNA tom qab transcriptional, (4) kev ruaj khov thiab kev thauj mus los ntawm RNA, (5) kev tswj hwm kev txhais lus, thiab (6) kev hloov pauv protein thiab kev puas tsuaj. Txhua theem muab "cov ntsiab lus tswj hwm" uas lub cell tuaj yeem siv los tswj cov zis kawg.
Kev tswj hwm epigenetic: tswj kev nkag mus rau DNA
Txheej kev tswj hwm thaum ntxov tshaj plaws yog epigenetics, uas yog cov kev hloov pauv uas cuam tshuam rau kev ua haujlwm ntawm cov noob caj noob ces yam tsis hloov pauv cov kab ke DNA. Cov txheej txheem tseem ceeb ntawm epigenetic suav nrog DNA methylation, kev hloov kho histone, thiab kev tswj hwm cov qauv chromatin.
DNA methylation feem ntau tshwm sim ntawm cytosines hauv CpG cheeb tsam thiab feem ntau cuam tshuam nrog kev txwv tsis pub muaj kev qhia tawm ntawm cov noob caj noob ces. Thaum tus txhawb nqa raug methylated, cov yam ntxwv transcription nyuaj dua rau khi, ua rau kev sau ntawv tsawg dua. Ntawm qhov tod tes, demethylation tuaj yeem qhib lub qhov rooj rau kev ua haujlwm ntawm noob caj noob ces. Kev hloov kho Histone - xws li acetylation thiab methylation ntawm histone tails - hloov pauv chromatin density. Histone acetylation feem ntau "loosen" chromatin (euchromatin), ua rau kev sau ntawv noob caj noob ces yooj yim dua, thaum qee hom histone methylation tuaj yeem compact chromatin (heterochromatin) thiab txwv tsis pub muaj kev qhia tawm.
Kev tswj hwm epigenetic yog qhov tseem ceeb rau kev sib txawv ntawm cov cell. Piv txwv li, thaum lub sijhawm embryonic txoj kev loj hlob, thaum xub thawj cov cell zoo sib xws "xauv" cov qauv qhia txog cov gene tshwj xeeb los ntawm cov cim epigenetic, yog li tswj tau qhov sib xws ntawm cov cell thaum cov cell faib. Cov yam ntxwv ib puag ncig xws li kev noj zaub mov, kev ntxhov siab, thiab kev raug tshuaj lom neeg kuj tuaj yeem cuam tshuam rau epigenome, piav qhia vim li cas cov yam ntxwv sab nraud tuaj yeem hloov kho kev qhia txog gene mus rau lub sijhawm ntev.
Kev tswj hwm kev sau ntawv: lub luag haujlwm ntawm cov neeg txhawb nqa, cov neeg txhawb nqa, thiab cov yam ntxwv sau ntawv
Qib kev tswj hwm uas tau kawm ntau tshaj plaws yog kev tswj hwm kev sau ntawv, uas yog kev tswj hwm cov txheej txheem ntawm kev tsim RNA los ntawm DNA los ntawm RNA polymerase. Hauv eukaryotes, kev sau ntawv feem ntau pib ntawm tus txhawb nqa, ib qho DNA kab lus uas cov txheej txheem sau ntawv tsim. Ntxiv rau tus txhawb nqa, muaj cov khoom txhawb nqa thiab cov khoom ntsiag to - cov khoom tswj hwm uas tuaj yeem ua rau kom nce lossis txo qhov nrawm ntawm kev sau ntawv, txawm tias nyob deb ntawm cov noob caj noob ces uas tau tswj hwm. DNA tuaj yeem quav ua voj voog, tso cai rau cov khoom txhawb nqa sib cuam tshuam nrog tus txhawb nqa ntawm cov protein txuas.
Cov yam ntxwv sau ntawv yog cov protein uas khi rau cov kab ke DNA tshwj xeeb thiab tswj RNA polymerase kev ua haujlwm. Muaj cov yam ntxwv sau ntawv dav dav uas xav tau los pib sau ntawv hauv ntau cov noob caj noob ces, thiab cov yam ntxwv sau ntawv tshwj xeeb uas tsuas yog ua haujlwm hauv cov noob caj noob ces lossis cov nqaij tshwj xeeb. Ntau yam yam ntxwv sau ntawv raug cuam tshuam los ntawm cov teeb liab ntawm tes, xws li cov tshuaj hormones, cov yam ntxwv loj hlob, lossis cov xwm txheej kev ntxhov siab. Thaum lub teeb liab tuaj txog, cov yam ntxwv sau ntawv tuaj yeem ua haujlwm los ntawm phosphorylation, kev hloov pauv qhov chaw (piv txwv li, nkag mus rau hauv lub nucleus), lossis kev sib cuam tshuam nrog cov neeg koom tes thiab cov neeg koom tes.
Hauv cov kab mob bacteria, kev tswj hwm transcriptional feem ntau piav qhia los ntawm lub tswv yim ntawm operons, xws li lac operon hauv Escherichia coli. Hauv lac operon, qhov muaj lactose ua rau lub repressor tsis ua haujlwm, tso cai rau cov noob lactose-zom kom raug sau. Ntxiv mus, kev muaj glucose cuam tshuam rau CAP-cAMP protein, uas ua rau kev sau ntawv nce ntxiv thaum glucose qis. Qhov piv txwv no qhia tau hais tias kev tswj hwm gene tuaj yeem koom ua ke ntau lub cim ib puag ncig tib lub sijhawm.
Kev ua RNA tom qab kev sau ntawv: kev sib txuas thiab kev hloov pauv ntawm cov khoom noob caj noob ces
Hauv cov eukaryotes, cov RNA tshiab uas tau sau ua ntej (pre-mRNA) yuav tsum tau ua tiav ua ntej nws dhau los ua mRNA laus. Cov txheej txheem no suav nrog kev ntxiv lub hau 5', polyadenylation ntawm qhov kawg 3' (poly-A tus tw), thiab splicing kom tshem tawm cov introns thiab koom nrog exons. Kev tswj hwm ntawm theem no tuaj yeem hloov pauv hom protein tsim los ntawm ib lub noob caj noob ces.
Ib qho tseem ceeb yog kev sib txuas lwm txoj hauv kev, uas cov kev sib xyaw ua ke ntawm cov exons tau sib txuas ua ke los tsim cov protein isoforms sib txawv. Kev sib txuas lwm txoj hauv kev tso cai rau ntau yam protein ntau yam yam tsis tau nce tus lej ntawm cov noob caj noob ces. Kev tswj hwm kev sib txuas yog tswj los ntawm RNA-binding proteins thiab cov teeb liab sib lawv liag ntawm pre-mRNA. Cov qauv sib txuas tuaj yeem sib txawv hauv cov nqaij sib txawv, tso cai rau ib lub noob caj noob ces los tsim cov khoom nrog lub luag haujlwm tshwj xeeb rau cov nqaij ntawd.
Kev ruaj khov thiab kev thauj mus los ntawm mRNA: tswj hwm "lub neej" ntawm cov lus qhia txog noob caj noob ces
Thaum cov mRNA loj hlob tiav lawm, cov cell tuaj yeem tswj tau nws lub sijhawm ntev npaum li cas ua ntej nws puas tsuaj. Qhov ruaj khov ntawm mRNA txiav txim siab seb nws tuaj yeem tsim cov protein ntau npaum li cas. Qee thaj chaw ntawm mRNA, tshwj xeeb tshaj yog thaj chaw 3' untranslated (3' UTR), muaj cov ntsiab lus uas khi cov protein tswj hwm lossis RNAs me me, cuam tshuam rau kev puas tsuaj thiab kev txhais lus zoo.
Ntxiv mus, mRNA yuav tsum tau thauj los ntawm lub nucleus mus rau cytoplasm. Qee zaum, mRNA kuj tseem "taw qhia" mus rau qhov chaw tshwj xeeb hauv lub cell (piv txwv li, hauv cov hlab ntsha, mus rau dendrites lossis axons). Qhov chaw ntawm mRNA tso cai rau kev tsim cov protein kom tshwm sim ze rau nws qhov chaw ua haujlwm, ua rau muaj kev ua haujlwm zoo thiab qhov tseeb ntawm cov lus teb ntawm lub cellular.
RNA tsis-coding thiab RNA cuam tshuam
Tsis yog txhua txoj kev tswj hwm ntawm kev qhia tawm ntawm cov noob caj noob ces vam khom cov protein. Cov RNAs uas tsis yog coding, xws li microRNAs (miRNAs) thiab cov RNAs me me uas cuam tshuam (siRNAs), yog cov tswj hwm tseem ceeb hauv ntau yam kab mob. miRNAs tuaj yeem khi rau cov mRNAs uas tsom mus rau thiab tiv thaiv kev txhais lus lossis ua kom lawv puas tsuaj sai dua. Lub tshuab no, hu ua RNA cuam tshuam (RNAi), ua lub luag haujlwm hauv kev tswj hwm kev loj hlob, kev tiv thaiv kab mob, thiab kev ruaj khov ntawm genome.
Lwm cov RNA uas tsis yog coding, xws li cov RNA uas tsis yog coding ntev (lncRNAs), tuaj yeem cuam tshuam rau kev qhia txog gene hauv ntau txoj kev - los ntawm kev coj cov chromatin modification complexes mus rau qhov chaw tshwj xeeb mus rau kev ua haujlwm ua "sponges" uas khi miRNAs kom lawv tsis tuaj yeem tiv thaiv cov mRNAs uas xav tau.
Kev tswj hwm kev txhais lus thiab tom qab kev txhais lus: kev tswj hwm ntawm qib protein
Txawm tias thaum mRNA muaj lawm los xij, cov cell tseem tuaj yeem tswj tau seb nws puas raug txhais ua protein. Kev tswj hwm kev txhais lus yog qhov tseem ceeb thaum cov cell xav tau kev teb sai, xws li thaum muaj kev ntxhov siab. Cov yam ntxwv pib txhais lus tuaj yeem ua haujlwm lossis txwv tsis pub, ua rau nce lossis txo qis kev tsim cov protein tshwj xeeb.
Tom qab ua ib qho protein lawm, kev tswj hwm tom qab kev txhais lus txuas ntxiv mus, suav nrog kev tais, kev sib cais, kev ntxiv cov pab pawg tshuaj (xws li phosphorylation, glycosylation, ubiquitination), thiab kev tswj hwm nws qhov chaw nyob hauv lub cell. Ubiquitination feem ntau cim cov protein rau kev puas tsuaj los ntawm proteasome. Ua li no, cov cell tuaj yeem tswj cov protein kom nruj, tshem tawm cov protein puas tsuaj, lossis sai sai nres kev xa xov.
Kev sib koom ua ke ntawm cov cim thiab qhov tseem ceeb ntawm kev tswj hwm kev qhia tawm ntawm cov noob caj noob ces
Hauv cov kab mob, tag nrho cov txheej txheem tswj hwm saum toj no ua haujlwm ua ke. Piv txwv li, cov tshuaj hormones steroid tuaj yeem nkag mus rau hauv cov hlwb thiab khi rau cov receptors uas ua haujlwm ua cov yam ntxwv sau ntawv. Cov receptors no tom qab ntawd nrhiav cov coactivators uas hloov cov histones kom qhib chromatin, txhim kho kev sau ntawv ntawm cov noob caj noob ces. Cov mRNA uas tshwm sim tuaj yeem dhau los ntawm kev sib txuas lwm txoj hauv kev nyob ntawm hom hlwb, thiab tom qab ntawd raug txhais nrog kev ua haujlwm sib txawv nyob ntawm cov xwm txheej metabolic.
Kev tswj hwm kev qhia tawm ntawm cov noob caj noob ces kuj yog qhov tseem ceeb rau kev hloov pauv ntawm cov kab mob mus rau lawv qhov chaw nyob. Hauv cov kab mob me me, kev hloov pauv ntawm kev qhia tawm ntawm cov noob caj noob ces tso cai rau lawv kom muaj sia nyob qhov hloov pauv ntawm qhov kub thiab txias, pH, lossis kev muaj cov as-ham. Hauv cov nroj tsuag, kev tswj hwm cov noob caj noob ces pab teb rau qhov qhuav, ntsev, thiab kev tawm tsam ntawm cov kab mob. Hauv cov tsiaj, lub cev tiv thaiv kab mob vam khom kev tswj hwm kev qhia tawm ntawm cov noob caj noob ces los ua kom cov noob caj noob ces rau cytokines, cov tshuaj tiv thaiv kab mob, thiab lwm yam tshuaj tiv thaiv sai sai tab sis tswj tau.
Kev kaw
Kev tswj hwm kev qhia tawm ntawm cov noob caj noob ces hauv cov kab mob yog ib qho system nyuaj uas tso cai rau ib lub genome los tsim ntau hom cell thiab cov lus teb ntawm lub cev. Los ntawm kev tswj hwm kev nkag mus rau DNA, tswj kev sau ntawv, hloov kho thiab xaiv RNA, tswj kev txhais lus, thiab txiav txim siab qhov hmoo ntawm cov protein, cov cell muaj peev xwm hloov kho rau cov kev xav tau sab hauv thiab kev hloov pauv ib puag ncig. Kev nkag siab txog kev tswj hwm kev qhia tawm ntawm cov noob caj noob ces tsis yog qhov tseem ceeb rau kev tshawb fawb yooj yim xwb tab sis kuj yog lub hauv paus rau kev txhim kho cov kev kho mob niaj hnub xws li kev kho mob raws li epigenetic, kev kho mob noob caj noob ces, thiab kev cuam tshuam raws li RNA. Raws li genomics thiab systems biology technologies nce qib, kev tshawb fawb txog kev tswj hwm kev qhia tawm ntawm cov noob caj noob ces yuav qhia ntau ntxiv txog kev nkag siab txog yuav ua li cas cov kab mob loj hlob, hloov kho, thiab tswj lawv txoj kev noj qab haus huv.
