Tseng Yu-Chun, Cabot Birgit, Cabot Ryan A
Department of Animal Sciences, Purdue University, West Lafayette, Indiana.
Mol Reprod Dev. 2017 Dec;84(12):1250-1256. doi: 10.1002/mrd.22924. Epub 2017 Nov 26.
Mammalian embryos undergo dramatic epigenetic remodeling that can have a profound impact on both gene transcription and overall embryo developmental competence. Members of the SWI/SNF (Switch/Sucrose non-fermentable) family of chromatin-remodeling complexes reposition nucleosomes and alter transcription factor accessibility. These large, multi-protein complexes possess an SNF2-type ATPase (either SMARCA4 or SMARCA2) as their core catalytic subunit, and are directed to specific loci by associated subunits. Little is known about the identity of specific SWI/SNF complexes that serve regulatory roles during cleavage development. ARID1A, one of the SWI/SNF complex subunits, can affect histone methylation in somatic cells; here, we determined the developmental requirements of ARID1A in porcine oocytes and embryos. We found ARID1A transcript levels were significantly reduced in 4-cell porcine embryos as compared to germinal vesicle-stage oocytes, suggesting that ARID1A would be required for porcine cleavage-stage development. Indeed, injecting in vitro-matured and fertilized porcine oocytes with double-stranded interfering RNAs that target ARID1A, and evaluating their phenotype after seven days, revealed that the depletion of ARID1A results in significantly fewer cells than their respective control groups (p < 0.001).
哺乳动物胚胎经历剧烈的表观遗传重塑,这可能对基因转录和整体胚胎发育能力产生深远影响。染色质重塑复合物的SWI/SNF(开关/蔗糖非发酵)家族成员重新定位核小体并改变转录因子的可及性。这些大型多蛋白复合物以SNF2型ATP酶(SMARCA4或SMARCA2)作为其核心催化亚基,并由相关亚基引导至特定基因座。关于在卵裂发育过程中起调节作用的特定SWI/SNF复合物的身份知之甚少。SWI/SNF复合物亚基之一ARID1A可影响体细胞中的组蛋白甲基化;在这里,我们确定了ARID1A在猪卵母细胞和胚胎中的发育需求。我们发现,与生发泡期卵母细胞相比,4细胞期猪胚胎中ARID1A转录水平显著降低,这表明ARID1A是猪卵裂期发育所必需的。事实上,向体外成熟和受精的猪卵母细胞注射靶向ARID1A的双链干扰RNA,并在七天后评估其表型,结果显示,与各自的对照组相比,ARID1A的缺失导致细胞数量显著减少(p < 0.001)。