Qhov sib txawv ntawm qhov sib txawv ntawm qhov sib txawv thiab imprinted X inactivation yog qhov random X inactivation yog inactivation ntawm leej txiv lossis leej niam X chromosome nrog qhov sib npaug ntawm lub sijhawm gastrulation hauv epiblast, thaum imprinted X inactivation yog ib qho tsis sib xws X inactivation. ntawm niam txiv muab tau X chromosome nyob rau hauv cov ntaub so ntswg extraembryonic ntawm cov tsiaj.
X inactivation yog ib txoj kev pom nyob rau hauv cov poj niam tsiaj. Feem ntau, cov poj niam muaj ob lub X chromosomes. Thiab, nyob rau hauv cov poj niam tsiaj, ib tug X chromosome ua inactive. Hauv lwm lo lus, ib qho X chromosome dhau los ua tus qauv hloov pauv tsis ua haujlwm. Thaum qhov no tshwm sim, qhov tshwj xeeb X chromosome tseem tsis ua haujlwm thoob plaws lub neej ntawm lub cell thiab nws cov xeeb ntxwv hauv lub cev. Tsis tas li ntawd, qhov tsis muaj zog X chromosome condenses rau hauv cov qauv compact hu ua Barr lub cev, thiab nws ruaj khov nyob rau hauv lub xeev ntsiag to. Tsis tas li ntawd, cov txheej txheem X inactivation nyob ntawm kev tswj ntawm ob qhov tsis-coding ntxiv RNAs. Txawm li cas los xij, X inactivation tsis tshwm sim hauv cov txiv neej, uas tsuas muaj ib qho X chromosome. Ntxiv mus, X inactivation tuaj yeem tshwm sim random los yog vim imprinting.
Random X Inactivation yog dab tsi?
Random x inactivation yog tus txheej txheem X inactivation ib txwm nyob rau hauv uas leej niam thiab leej txiv X chromosomes muaj qhov sib npaug ntawm qhov ua tsis tau. Qhov no tshwm sim nyob rau hauv placental mammals nrog rau tib neeg thaum lub sij hawm ntawm gastrulation nyob rau hauv lub epiblast. Lub inactivated chromosome tseem tsis ua haujlwm thoob plaws hauv lub neej ntawm tes thiab nws cov xeeb leej xeeb ntxwv.
Daim duab 01: Random X inactivation
Ntxiv mus, qhov no yog ib txoj hauv kev ua kom tau txais nyiaj ntau npaum li cas thiab tau pom thawj zaug hauv cov hlwb somatic ntawm poj niam tsiaj. X-inactivation center (Xic) nyob rau ntawm X chromosome tswj qhov random X inactivation. Yog li, vim tsis muaj X inactivation, noob ntawm tag nrho X chromosome ua transcriptionally silenced.
Dab tsi yog Imprinted X Inactivation?
Ib tug xeeb ntxwv tau txais ob daim qauv ntawm cov noob los ntawm nws niam nws txiv. Ib daim ntawv yog los ntawm leej niam thiab lwm qhov yog los ntawm leej txiv. Thiab, feem ntau ntawm cov sij hawm, ob daim ntawv luam ntawm cov noob yog kev ua haujlwm lossis hauv daim ntawv nquag. Txawm li cas los xij, qee zaus, tsuas yog ib daim ntawv theej tseem nyob hauv nws daim ntawv nquag thaum lwm tus nyob hauv daim ntawv tsis ua haujlwm. Yog li ntawd, ib daim ntawv raug muab "rau" thaum lwm qhov yog "tawm". Thiab, txoj kev no yog hu ua genomic imprinting. Genomic imprinting feem ntau tshwm sim nyob rau hauv thawj theem ntawm kev loj hlob ntawm ib tug kab mob thiab nws tsis ua raws li cov cai ntawm ib txwm Mendelian qub txeeg qub teg. Nyob rau hauv cov kab mob extraembryonic ntawm nas, tus niam txiv muab tau X tau raug xaiv los ua kom tsis muaj zog. Li no, nws yog ib hom nonrandom X inactivation. Ntawm no, imprinted X inactivation ntawm niam txiv X chromosome tshwm sim. Tag nrho cov nas hlwb tau txais qhov imprinted X inactivation nyob rau hauv 4-8 cell theem embryos.
Dab tsi zoo sib xws ntawm Random thiab Imprinted X Inactivation?
- Random thiab imprinted X inactivation yog ob hom X inactivation tshwm sim hauv cov poj niam tsiaj.
- Ob txheej txheem ua rau kev hloov pauv ntawm cov noob feem ntau ntawm ib qho ntawm ob X-chromosomes.
- X-inactivation center (Xic) nyob rau ntawm X chromosome tswj ob qho tib si random thiab imprinted X inactivation.
- Qhov tsis yog RNA Xist yog xav tau rau kev pib ntawm ob qho tib si random thiab imprinted X inactivation.
Qhov txawv ntawm Random thiab Imprinted X Inactivation yog dab tsi?
Muaj ob hom X inactivation: imprinted thiab random. Hauv random X inactivation, leej niam thiab leej txiv X chromosomes muaj qhov sib npaug ntawm qhov ua tsis tau. Nyob rau hauv imprinted X inactivation, ib tug niam txiv X chromosome yog nyiam nyob ntsiag to nyob rau hauv lub placenta ntawm eutherian mammals, raws li zoo raws li nyob rau hauv tag nrho cov hlwb ntawm yav dhau los marsupial mammals. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm random thiab imprinted X inactivation. Imprinted X inactivation yog tsawg ua tiav thiab tsis ruaj khov dua random X inactivation.
Cov hauv qab no infographic qhia txog qhov sib txawv ntawm qhov sib txawv ntawm qhov tsis sib xws thiab luam tawm X inactivation.
Summary – Random vs Imprinted X Inactivation
X inactivation yog kev tua ntawm ib qho X chromosome. Nws tuaj yeem tshwm sim los ntawm random inactivation lossis los ntawm imprinted X inactivation. Tsis tas li ntawd, nws tshwm sim hauv qee cov poj niam tsiaj. Hauv random X inactivation, leej niam thiab leej txiv X chromosome muaj qhov sib npaug ntawm qhov ua tsis tau. Nyob rau hauv sib piv, nyob rau hauv imprinted X inactivation, feem ntau yog leej txiv muab tau los X chromosome raug xaiv kom inactivated. Yog li ntawd, nws tsis yog ib tug random txheej txheem. Ntxiv mus, random X inactivation tshwm sim thaum lub sij hawm implantation thaum imprinted X inactivation tshwm sim nyob rau hauv tag nrho cov hlwb, thaum ntxov nyob rau hauv preimplantation txoj kev loj hlob. Tsis tas li ntawd, random X inactivation tshwm sim nyob rau hauv embryonic kab mob thaum imprinted X inactivation tshwm sim nyob rau hauv extraembryonic kab. Yog li, qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm random thiab imprinted X inactivation.
