Sex determines the expression level of one third of the actively expressed genes in bovine blastocysts
Sex determines the expression level of one third of the actively expressed genes in bovine blastocysts
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DOI：
10.1073/pnas.0913843107
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发表时间：
2010-02-23
影响因子：
11.1
通讯作者：
Gutierrez-Adan, A.
中科院分区：
文献类型：
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作者：
Bermejo-Alvarez, P.;Rizos, D.;Gutierrez-Adan, A.
尽管常染色体KRs(Chr)在基因上相同，但男性和女性植入前胚胎可以表现出性别特异性的转录调控。为了在mRNA水平上阐明性别差异，我们通过DNA微阵列比较了9组60头牛的雄性和雌性囊胚的基因表达模式。几乎三分之一的检测到的转录本表现出性别二型性(2921个转录本；假发现率，P<；0.05)，这表明在没有激素影响的情况下，性别基因对常染色体基因施加了广泛的转录调节。对6个性二型性相似的活体胚胎进行了qPCR分析。本体论分析表明，雌性的整体转录水平较高，雄性的蛋白质代谢更活跃。在Y-Chr中发现了一个与参与剪接体组装过程中网络相互作用的X连锁基因同源的基因。大多数X连锁表达的转录本(88.5%)在雌性中上调，但大多数(70%)的X-Chr表达倍数低于1.6，表明X-Chr的部分失活是在囊胚期实现的。在发生1.6倍以上变化的雌性胚胎中，几乎一半上调的转录本存在于X-Chr中，其中8个被选择通过与孤雌胚胎的基因表达比较来确定可能的父系印记。5个(Bex、CAPN6、BEX2、SRPX2和UBE2a)在雌性中的表达高于单性生殖，这表明它们主要由父本遗传的X-Chr表达，印迹可能增加了X-Chr剂量加倍引起的转录倾斜。
Although genetically identical for autosomal Chrs (Chr), male and female preimplantation embryos could display sex-specific transcriptional regulation. To illustrate sex-specific differences at the mRNA level, we compared gene-expression patterns between male and female blastocysts by DNA microarray comparison of nine groups of 60 bovine in vitro-produced blastocysts of each sex. Almost one-third of the transcripts detected showed sexual dimorphism (2,921 transcripts; false-discovery rate, P < 0.05), suggesting that in the absence of hormonal influences, the sex Chrs impose an extensive transcriptional regulation upon autosomal genes. Six genes were analyzed by qPCR in in vivo-derived embryos, which displayed similar sexual dimorphism. Ontology analysis suggested a higher global transcriptional level in females and a more active protein metabolism in males. A gene homolog to an X-linked gene involved in network interactions during spliceosome assembly was found in the Y-Chr. Most of the X-linked-expressed transcripts (88.5%) were up-regulated in females, but most of them (70%) exhibited fold-changes lower than 1.6, suggesting that X-Chr inactivation is partially achieved at the blastocyst stage. Almost half of the transcripts up-regulated in female embryos exhibiting more than 1.6-fold change were present in the X-Chr and eight of them were selected to determine a putative paternal imprinting by gene expression comparison with parthenogenetic embryos. Five (BEX, CAPN6, BEX2, SRPX2, and UBE2A) exhibited a higher expression in females than in parthenotes, suggesting that they are predominantly expressed by the paternal inherited X-Chr and that imprinting may increase the transcriptional skew caused by double X-Chr dosage.