Imbalance between the expression dosages of X-chromosome and autosomal genes in mammalian oocytes.
Imbalance between the expression dosages of X-chromosome and autosomal genes in mammalian oocytes.
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DOI：
10.1038/srep14101
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发表时间：
2015-09-15
影响因子：
4.6
通讯作者：
Akutsu H
中科院分区：
文献类型：
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作者：
Fukuda A;Tanino M;Matoba R;Umezawa A;Akutsu H
卵母细胞与其他细胞类型相比具有独特的特征。在小鼠和人类卵母细胞中，两条X染色体保持在活跃状态。先前的微阵列研究表明，表达状态的平衡在单倍体卵母细胞中得以维持。在这里，我们研究了使用RNA测序技术在小鼠和人类卵母细胞的转录本。小鼠未成熟卵母细胞中X染色体与常染色体基因的中位表达比值（X：A）随着基因表达水平的增加而增加，最高可达1。然而，在成熟卵母细胞中，所有表达类别的比率均低于1。此外，我们观察到一个显着低的比例，导致X-连锁基因的双峰表达模式。成熟卵母细胞中X：A的低表达率与DNA甲基化无关。虽然成熟的人类卵母细胞表现出略低的X：A表达比，这是低表达的X连锁基因的偏高频率，而不是双峰状态的结果。我们认为，这种X染色体和常染色体基因表达剂量之间的不平衡是缺乏X染色体失活的哺乳动物卵母细胞中转录本的一个特征。
Oocytes have unique characteristics compared with other cell types. In mouse and human oocytes, two X chromosomes are maintained in the active state. Previous microarray studies have shown that the balance of the expression state is maintained in haploid oocytes. Here, we investigated transcripts using RNA-sequence technology in mouse and human oocytes. The median expression ratio between X chromosome and autosomal genes (X:A) in immature mouse oocytes increased as the gene expression levels increased, reaching a value of 1. However, the ratio in mature oocytes was under 1 for all expression categories. Moreover, we observed a markedly low ratio resulting from the bimodal expression patterns of X–linked genes. The low X:A expression ratio in mature oocyte was independent of DNA methylation. While mature human oocytes exhibited a slightly low X:A expression ratio, this was the result of the skewed high frequency of lowly expressed X-linked genes rather than the bimodal state. We propose that this imbalance between the expression dosages of X-chromosome and autosomal genes is a feature of transcripts in mammalian oocytes lacking X-chromosome inactivation.