新功能、新界面、新体验,扫描即可下载生物谷APP!
首页 » 组学 » 染色体X&Y?NO!影响性别分化的新型遗传物质—miRNAs

染色体X&Y?NO!影响性别分化的新型遗传物质—miRNAs

来源:生物谷 2014-08-20 09:11

2014年8月20日 讯 /生物谷BIOON/ --男性和女性的特征在很多方面都很好区分,长期以来研究人员一直认为男性和女性机体DNA的遗传差异是决定其外在表现差异的主要原因,在过去科学家们主要在研究编码蛋白质的基因如何作为一个性别决定子来发挥作用。然而近日刊登在国际杂志Genetics上的一篇研究论文中,来自冷泉港实验室的研究人员通过对果蝇进行研究发现,一系列短的RNA分子,即miRNAs或许在区分果蝇的雌雄上也扮演着重要的角色。

miRNA分子是一种短链RNA分子,其可以调节一个或多个编码蛋白的基因的活性。miRNA还可以通过靶向作用使得基因沉默,阻断复杂的遗传程序。这项研究中,研究者揭示了miRNA如何在果蝇中引发性别差异,我们可能从来都不会注意,但是雌雄果蝇的差异却非常明显,这就好比其它动物一样,比如雌性果蝇的色素沉着和腹节长度都比雄性个体多25%。

研究者Greg Hannon表示,miRNA的不同对于塑造雌雄果蝇结构的差异非常重要,实际上在果蝇发育期间,miRNA还可以调节决定果蝇性别的蛋白质的功能;在动物成年后miRNA对于性别分化仍然很重要,其可以向精子细胞或卵细胞发送信号促进其发育,确保后代的繁衍。

从成年果蝇机体中移除miRNA就会引发其不育,从某种意义上来讲,一旦失去miRNA分子,果蝇就会同时具有两性特征,因此miRNA分子对于性别的分化具有非常大的影响。研究者表示,这项研究中的某些miRNA分子,比如let-7,由于其具有某种特性,因此在进化过程中被机体可以保存下来,人类和其他动物携带该分子的其它形式。

在细胞和组织水平上有许多miRNAs可以调节性别分化,但是研究者们仍然有很多地方去研究,来帮助理解人类的性别分化,从而为揭示出生及发育缺陷的分子机制提供一定的思路和希望。(生物谷Bioon.com)

A Genome-Wide Survey of Sexually Dimorphic Expression of Drosophila miRNAs Identifies the Steroid Hormone-Induced miRNA let-7 as a Regulator of Sexual Identity

Delphine Fagegaltier 1,*, Annekatrin König 2, Assaf Gordon 1, Eric C. Lai 3, Thomas R. Gingeras 1, Gregory J. Hannon 1 and Halyna R. Shcherbata 2,**

MiRNAs bear an increasing number of functions throughout development and in the aging adult. Here we address their role in establishing sexually dimorphic traits and sexual identity in male and female Drosophila. Our survey of miRNA populations in each sex identifies sets of miRNAs differentially expressed in male and female tissues across various stages of development. The pervasive sex-biased expression of miRNAs generally increases with the complexity and sexual dimorphism of tissues, gonads revealing the most striking biases. We find that the male-specific regulation of the X chromosome is relevant to miRNA expression on two levels. First, in the male gonad, testis-biased miRNAs tend to reside on the X chromosome. Second, in the soma, X-linked miRNAs do not systematically rely on dosage compensation. We set out to address the importance of a sex-biased expression of miRNAs in establishing sexually dimorphic traits. Our study of the conserved let-7-C miRNA cluster controlled by the sex-biased hormone ecdysone places let-7 as a primary modulator of the sex determination hierarchy. Flies with modified let-7 levels present doublesex-related phenotypes and express sex determination genes normally restricted to the opposite sex. In testes and ovaries, alterations of the ecdysone induced let-7 result in aberrant gonadal somatic cell behavior and non cell-autonomous defects in early germline differentiation. Gonadal defects as well as aberrant expression of sex determination genes persist in aging adults under hormonal control. Together, our findings place ecdysone and let-7 as modulators of a somatic systemic signal that helps establish and sustain sexual identity in males and females and differentiation in gonads. This work establishes the foundation for a role of miRNAs in sexual dimorphism and demonstrates that similar to vertebrate hormonal control of cellular sexual identity exists in Drosophila.

温馨提示:87%用户都在生物谷APP上阅读,扫描立刻下载! 天天精彩!


相关标签

最新会议 培训班 期刊库