Qhov sib txawv tseem ceeb ntawm DNA methylation thiab histone acetylation yog DNA methylation ua rau methylated DNA bases uas ua rau cov noob tsis ua haujlwm, thaum histone acetylation yog kev hloov kho ntawm histone proteins txuam nrog cov qauv nucleosome.
Kev hloov pauv ntawm Epigenetic yog kev hloov kho uas ua rau muaj kev tswj hwm ntawm noob caj noob ces yam tsis ua rau muaj kev hloov pauv rau cov kab ke ntawm DNA. Hauv qhov no, ob qho kev hloov kho tshuaj lom neeg tseem ceeb, DNA methylation thiab kev hloov kho histone, coj qhov chaw los ua kom muaj kev hloov pauv hauv DNA, ua rau kev ua kom lossis tsis ua haujlwm ntawm cov noob qhia.
DNA Methylation yog dab tsi?
DNA methylation yog ib qho kev hloov pauv tseem ceeb hauv cov hlwb. Nws hloov lossis tswj cov kev qhia gene. Hauv qhov tshwm sim no, DNA bases yog methylated nrog kev pab ntawm methyl transferases. Cov pab pawg methyl raug xa mus los ntawm S-adenosyl methionine. Qhov random methylation ntawm DNA hauv paus ua rau qhov tsis ua haujlwm ntawm cov noob qhia. Thaum methylation ntawm DNA tshwm sim nyob rau hauv cov cheeb tsam tswj hwm ntawm DNA xws li cov txheej txheem txhawb nqa, CpG Islands, cov ntsiab lus sib thooj thiab qhov nruab nrab, cov kab ke no tau hloov kho, ua rau poob ntawm cov kev tswj hwm thaj tsam ntawd. Raws li qhov tshwm sim, cov xwm txheej hloov pauv yuav tsis khi raws li qhov xav tau, thiab kev tsis ua haujlwm lossis kev txo qis ntawm cov noob qhia ntawm qib transcriptional tshwm sim. Tsis tas li ntawd, cov kev hloov kho DNA no kuj tseem yuav txo qhov kev sib raug zoo ntawm RNA polymerase kom nyob ruaj khov thaum lub sijhawm hloov pauv.
Daim duab 01: DNA Methylation
DNA methylation lossis hyper-methylation ntawm DNA cheeb tsam kuj ua rau genomic imprinting, uas yog txheej txheem tseem ceeb hauv kev kaw cov noob caj noob ces raws li ib txoj hauv kev los tswj cov kev qhia ntawm cov noob. Kev hloov pauv ua kom DNA methylation hauv cov noob. Ib puag ncig yam, kev ntxhov siab, noj zaub mov, cawv, thiab lwm yam exogenous kuj tseem qhib DNA methylation. Piv txwv li, cov qauv kev noj haus ntev ntev uas muaj cov muaj pes tsawg leeg ntawm cov methyl pub dawb tuaj yeem ua rau muaj kev ua kom muaj zog ntawm DNA methylation thaum lub sij hawm noj zaub mov ntev uas ua rau cov neeg pub noj methyl qis heev tuaj yeem ua rau demethylation ntawm DNA.
Histone Acetylation yog dab tsi?
Histone hloov kho yog lwm hom kev hloov pauv ntawm epigenetic uas ua rau muaj kev tswj hwm noob. Muaj ntau yam kev hloov kho tshuaj sib txawv ntawm qhov sib txawv histone proteins txuam nrog kev tsim nucleosome thaum lub koom haum chromosomal ntawm eukaryotes. Cov kev hloov kho no suav nrog phosphorylation, acetylation, methylation, glycosylation, thiab ubiquitination.
Daim duab 02: Histone Acetylation
Histon acetylation yog kho los ntawm acetyl transferase enzymes uas acetylate amino acid residues ntawm ntau histone subunits. Cov lysine amino acid residues ntawm histone proteins tau nkag acetylated. Tom qab acetylation, decondensation tshwm sim, tsim kom muaj cov qauv qhib dua. Qhov no yuav tso cai rau DNA tau nthuav tawm ntau dua rau kev ua kom transcriptional. Qhov kev hloov pauv kev coj ua no tshwm sim los ntawm kev decondensation ntawm cov qauv nucleosome yuav tso cai rau RNA polymerase thiab cov txheej txheem hloov pauv tau raug xaiv kom yooj yim los pib sau ntawv. Nyob rau hauv sib piv, thaum histone deacetylation tshwm sim, cov qauv nucleosome undergoes condensation, uas yuav tiv thaiv kom txhob muaj transcription.
Dab tsi zoo sib xws ntawm DNA Methylation thiab Histone Acetylation?
- Ob leeg yog cov kev hloov kho epigenetic uas tshwm sim los tswj cov noob caj noob ces.
- Ob leeg tsuas yog nyob hauv eukaryotes.
- Ntxiv mus, kev hloov kho tshuaj lom neeg los ntawm kev ua haujlwm enzymatic tshwm sim hauv ob qho xwm txheej.
- Exogenous yam xws li ib puag ncig, kev ntxhov siab, kev noj haus thiab cawv tswj ob txheej txheem.
- Ob txheej txheem yuav tsis ua rau muaj kev hloov pauv DNA.
- Cov txheej txheem no tshwm sim hauv lub nucleus.
Qhov txawv ntawm DNA Methylation thiab Histone Acetylation yog dab tsi?
DNA methylation thiab histone acetylation yog ob qho tib si hloov kho epigenetic. Txawm li cas los xij, thaum DNA methylation tshwm sim ntawm qib DNA, histone acetylation yog kev hloov kho tshuaj lom neeg uas muaj nyob hauv cov proteins raws li kev hloov pauv tom qab ntawm cov proteins histone. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm DNA methylation thiab histone acetylation. DNA methylation inactivates transcription thaum inhibiting pib transcription thiab txo RNA stability. Nyob rau hauv sib piv, histone acetylation yuav ua rau lub decondensation ntawm lub nucleosome ua rau kom ua rau transcription.
Cov hauv qab no qhia txog qhov sib txawv ntawm DNA methylation thiab histone acetylation hauv daim ntawv tabular rau ib sab ntawm kev sib piv.
Summary – DNA Methylation vs Histone Acetylation
Kev hloov pauv ntawm Epigenetic yog qhov tseem ceeb hauv kev coj ntau yam sib txawv rau txoj hauv kev ntawm noob caj noob ces los ntawm kev tswj hwm kev tswj hwm hauv kev teb rau kev hloov pauv ib puag ncig. DNA methylation thiab histone acetylation yog ob yam tseem ceeb ntawm cov txheej txheem epigenetic uas tsis ua haujlwm thiab qhib cov noob qhia, feem. Txawm hais tias ob lub tswv yim tsis hloov cov txheej txheem ntawm DNA, nws koom nrog hauv kev tsim cov kev hloov pauv ntawm DNA uas yog txhawb los yog inhibit gene qhia. DNA methylation ua rau hloov pauv DNA hauv paus los ntawm methylating lawv. Hauv qhov sib piv, histone acetylation yog acetylation ntawm cov amino acid residues, uas ua rau decondensed chromatin. Cov txheej txheem no tau qhib rau hauv cov lus teb rau stimuli thiab ua lub luag haujlwm tseem ceeb hauv kev tswj cov kev qhia ntawm ib qho gene. Yog li, qhov no qhia txog qhov sib txawv ntawm DNA methylation thiab histone acetylation.
