Epigenetics hauv Kev Tswj Xyuas Gene
Epigenetics yog ib ceg ntawm biology uas kawm txog kev hloov pauv hauv kev ua haujlwm ntawm cov noob caj noob ces uas tsis yog los ntawm kev hloov pauv ntawm DNA. Hauv lwm lo lus, epigenetics piav qhia txog yuav ua li cas qhib lossis kaw cov noob caj noob ces yam tsis tau hloov cov lej noob caj noob ces nws tus kheej. Lub tswv yim no tseem ceeb heev vim nws pab peb nkag siab tias vim li cas cov cell hauv lub cev uas sib koom tib cov DNA tuaj yeem muaj cov haujlwm sib txawv, xws li cov hlwb paj hlwb, cov hlwb nqaij, thiab cov hlwb ntshav. Epigenetics ua lub luag haujlwm tseem ceeb hauv kev tswj cov noob caj noob ces, cov txheej txheem ntawm kev tswj hwm thaum twg, qhov twg, thiab muaj zog npaum li cas ib qho noob caj noob ces tau qhia tawm.
Lub Hauv Paus ntawm Kev Tswj Xyuas Gene
Kev tswj cov noob caj noob ces yog ib txoj hauv kev uas cov cell siv los kho cov protein ntau raws li qhov xav tau. Cov noob caj noob ces "Active" raug hloov mus rau hauv RNA thiab tom qab ntawd txhais ua cov protein. Cov noob caj noob ces "Inactive", ntawm qhov tod tes, tsis tsim cov khoom ua haujlwm. Txoj kev tswj no yog qhov tseem ceeb rau kev loj hlob ntawm cov menyuam hauv plab, kev sib txawv ntawm cov cell, kev teb rau kev ntxhov siab, kev hloov pauv ib puag ncig, thiab kev tswj hwm cov haujlwm ntawm lub cev. Kev cuam tshuam ntawm kev tswj cov noob caj noob ces 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.
Hauv cov ntsiab lus no, epigenetics ua haujlwm zoo li ib lub kaw lus tswj hwm ntxiv rau saum lub genome. Yog tias lub genome zoo li phau ntawv qhia ua zaub mov, ces epigenetics yog tus cim lossis sau ntawv uas txiav txim siab seb cov zaub mov twg yuav tsum nyeem thiab nyeem ntau zaus npaum li cas.
Cov Txheej Txheem Tseem Ceeb ntawm Epigenetics
Muaj ntau txoj kev loj ntawm epigenetic uas cuam tshuam rau kev tswj hwm cov noob caj noob ces. Peb txoj kev uas feem ntau kawm yog DNA methylation, histone modification, thiab kev tswj hwm los ntawm non-coding RNA. Tag nrho peb txoj kev ua haujlwm sib koom tes los tswj kev nkag mus rau DNA thiab cov qib kev qhia tawm ntawm cov noob caj noob ces.
1. Kev ua kom DNA methylation
DNA methylation tshwm sim thaum ib pawg methyl (—CH₃) raug ntxiv rau hauv cytosine base, feem ntau nyob rau hauv cov cheeb tsam ntawm DNA nplua nuj nyob rau hauv CpG (cytosine-phosphate-guanine) base pairs. Kev ntxiv ntawm cov pawg methyl no feem ntau yog txuam nrog kev txwv tsis pub muaj kev qhia txog gene. Cov chaw tseem ceeb tshaj plaws ntawm methylation feem ntau yog cov gene promoters, cov cheeb tsam ntawm DNA uas tswj kev pib ntawm transcription.
Yog tias tus promoter muaj methylated ntau, cov transcription factors muaj teeb meem khi, thiab RNA polymerase tsis tuaj yeem ua haujlwm zoo. Yog li ntawd, cov gene feem ntau "ntsiag to." DNA methylation ua lub luag haujlwm tseem ceeb hauv cov txheej txheem ib txwm xws li X chromosome inactivation hauv cov poj niam thiab genomic imprinting, qhov twg gene expression raug cuam tshuam los ntawm cov poj koob yawm txwv.
2. Kev Hloov Kho Histone
DNA nyob rau hauv lub nucleus ntawm lub cell tsis yog tsuas yog lwj xwb; es, nws tau ntim ua ke nrog cov protein histone los tsim cov chromatin. Cov qauv no tuaj yeem nruj dua lossis xoob dua. Thaum chromatin nruj (heterochromatin), cov noob caj noob ces tsis yooj yim nkag mus thiab tsis tshua muaj peev xwm qhia tawm. Thaum chromatin xoob (euchromatin), cov noob caj noob ces yooj yim nkag mus thiab muaj peev xwm ua haujlwm ntau dua.
Cov histones tuaj yeem hloov pauv ntau yam tshuaj lom neeg, xws li acetylation, methylation, phosphorylation, thiab ubiquitination. Histone acetylation, tshwj xeeb tshaj yog ntawm lysine residues, feem ntau yog txuam nrog kev ua haujlwm ntawm cov noob caj noob ces vim nws ua rau chromatin qhib ntau dua. Ntawm qhov tod tes, histone methylation tuaj yeem ua rau kev ua haujlwm lossis kev txwv nyob ntawm qhov chaw thiab tus lej ntawm cov pab pawg methyl ntxiv. Kev sib xyaw ua ke ntawm cov kev hloov pauv no tsim cov "histone code" uas pab txiav txim siab lub xeev ntawm kev qhia tawm noob caj noob ces.
3. RNA tsis coding
Tsis yog txhua RNA raug txhais ua protein. Ntau cov RNA uas tsis yog coding ua lub luag haujlwm hauv kev tswj hwm gene, suav nrog microRNAs (miRNAs), RNAs uas tsis yog coding ntev (lncRNAs), thiab RNAs me me uas cuam tshuam (siRNAs). Piv txwv li, MicroRNAs tuaj yeem txuas rau cov mRNAs uas koj xav tau thiab ua rau puas tsuaj lossis txwv tsis pub txhais lus, yog li ntawd txo cov protein tsim tawm.
Cov RNA uas tsis yog coding kuj tseem tuaj yeem coj cov epigenetic protein complexes mus rau qhov chaw tshwj xeeb hauv lub genome, yog li ntawd cuam tshuam rau DNA methylation lossis histone modifications. Ua li no, cov RNA uas tsis yog coding ua haujlwm ua cov tswj hwm zoo uas txiav txim siab cov qib tshwj xeeb ntawm kev qhia tawm gene.
Epigenetics hauv Kev Loj Hlob ntawm Cell thiab Kev Sib Txawv
Ib qho ntawm lub luag haujlwm tseem ceeb tshaj plaws ntawm epigenetics yog nyob rau hauv kev loj hlob ntawm cov kab mob. Thaum ib tug zygote loj hlob mus rau hauv ntau hom cell, txhua lub cell nqa tib lub DNA tab sis muaj ib qho kev qhia tawm gene sib txawv. Qhov kev pab cuam no tau tsim thiab tswj hwm los ntawm cov cim epigenetic.
Piv txwv li, cov hlwb noob muaj cov chromatin qhib uas tso cai rau ntau cov noob kom ua haujlwm. Thaum lawv sib txawv, cov cim epigenetic ua rau cov kev xaiv ntawm cov noob uas raug ua haujlwm nqaim dua, ua rau cov hlwb tshwj xeeb, xws li cov hlwb siab ua kom cov noob tshem tawm cov tshuaj lom lossis cov hlwb pancreatic ua kom cov noob tsim insulin ua haujlwm.
Kev Cuam Tshuam Ib puag ncig rau Epigenetics
Epigenetics kuj txuas qhov sib txawv ntawm cov noob caj noob ces thiab ib puag ncig. Cov yam xws li kev noj zaub mov zoo, kev ntxhov siab, kev raug tshuaj lom, kev haus luam yeeb, kev ua ub ua no, thiab txawm tias kev pw tsaug zog tuaj yeem cuam tshuam rau cov cim epigenetic. Piv txwv li, qhov tsis txaus ntawm qee cov as-ham uas ua haujlwm ua cov methyl donors (xws li folate thiab vitamin B12) tuaj yeem cuam tshuam rau cov qauv DNA methylation.
Kev raug cov pa phem lossis cov tshuaj lom neeg kuj tseem tuaj yeem hloov pauv histone modifications thiab DNA methylation, thaum kawg cuam tshuam rau kev pheej hmoo ntawm kab mob. Qhov no yog ib qho laj thawj vim li cas kev ua neej nyob tuaj yeem cuam tshuam rau kev noj qab haus huv mus sij hawm ntev , txawm tias nyob rau theem molecular.
Epigenetics thiab Kab Mob
Qhov tsis sib npaug ntawm kev tswj hwm epigenetic tuaj yeem ua rau muaj ntau yam kab mob. Hauv mob qog noj ntshav, cov qauv DNA methylation feem ntau hloov pauv loj heev. Qee cov noob caj noob ces tiv thaiv qog tuaj yeem raug ntsiag to vim yog promoter hypermethylation, ua rau cov hlwb tsis muaj cov txheej txheem tswj kev loj hlob. Ntawm qhov tod tes, lwm thaj chaw ntawm lub genome tuaj yeem dhau los ua hypomethylated, ua rau chromosomal tsis ruaj khov.
Ntxiv rau mob qog noj ntshav, kev cuam tshuam epigenetic kuj tseem muaj feem cuam tshuam nrog cov kab mob neurodegenerative xws li Alzheimer's thiab Parkinson's, cov kab mob metabolic xws li ntshav qab zib hom 2, thiab cov kab mob autoimmune. Txawm tias qee qhov kev loj hlob tsis zoo xws li Prader-Willi thiab Angelman syndromes kuj muaj feem cuam tshuam nrog epigenetic genomic imprinting.
Epigenetics ua lub hom phiaj kho mob
Vim tias kev hloov pauv epigenetic tuaj yeem thim rov qab tau, lawv yog lub hom phiaj zoo rau kev tsim tshuaj. Ntau txoj kev kho mob qog noj ntshav twb siv cov tshuaj inhibitors ntawm cov enzymes uas koom nrog DNA methylation lossis histone deacetylation, xws li DNMT inhibitors thiab HDAC inhibitors. Cov tshuaj no tuaj yeem rov ua kom cov noob caj noob ces ntsiag to, suav nrog cov noob caj noob ces tiv thaiv qog noj ntshav.
Txawm li cas los xij, kev kho mob epigenetic muaj kev cov nyom vim tias kev hloov pauv epigenetic tuaj yeem tshwm sim hauv ntau lub noob tib lub sijhawm. Xav tau cov tswv yim meej dua kom ua tiav cov txiaj ntsig tsom mus rau thiab txo cov kev phiv. Kev tsim cov thev naus laus zis xws li CRISPR-based epigenome editing kuj pib qhib lub sijhawm los hloov cov cim epigenetic ntawm cov chaw tshwj xeeb yam tsis txiav DNA.
Epigenetics hauv Kev Txais Txiaj Ntsig
Ib lo lus nug txaus nyiam yog seb qhov kev hloov pauv epigenetic puas tuaj yeem tau txais los ntawm noob caj noob ces. Hauv qee yam tsiaj txhu, qee cov cim epigenetic tuaj yeem nyob mus ib txhis. Hauv tib neeg, feem ntau cov cim epigenetic yog "pib dua" thaum lub sijhawm tsim gamete thiab kev loj hlob ntawm lub embryonic thaum ntxov. Txawm li cas los xij, muaj cov cim qhia tias qee qhov kev hloov pauv tshwj xeeb yuav raug txais los ntawm cov txheej txheem nyuaj, txawm hais tias qhov no tseem yog thaj chaw tshawb fawb nquag.
Xaus
Epigenetics yog ib qho tseem ceeb hauv kev tswj hwm cov noob caj noob ces vim nws txiav txim siab txog kev nkag mus rau DNA thiab cov qib kev qhia tawm ntawm cov noob caj noob ces yam tsis hloov pauv cov noob caj noob ces. Los ntawm DNA methylation, kev hloov kho histone, thiab non-coding RNA, cov cell tuaj yeem tswj hwm cov noob caj noob ces ua haujlwm raws li kev xav tau kev loj hlob thiab cov lus teb ib puag ncig. Kev nkag siab txog epigenetics pab piav qhia txog kev sib txawv ntawm cov cell, kev cuam tshuam ntawm txoj kev ua neej rau kev noj qab haus huv, thiab keeb kwm ntawm ntau yam kab mob. Ntxiv mus, epigenetics muab cov cib fim tseem ceeb hauv kev kho mob, tshwj xeeb tshaj yog vim nws qhov xwm txheej hloov pauv tau. Nrog kev tshawb fawb txuas ntxiv, epigenetics muaj peev xwm los ua lub hauv paus tseem ceeb rau kev kho mob kom raug thiab tus kheej yav tom ntej.
