Yamaguchi Takeshi, Kataoka Kensuke, Watanabe Kenji, Orii Hidefumi
Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297, Japan.
Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297, Japan.
Mech Dev. 2014 Feb;131:15-23. doi: 10.1016/j.mod.2013.11.002. Epub 2013 Nov 26.
DEADSouth mRNA encoding the RNA helicase DDX25 is a component of the germ plasm in Xenopus laevis. We investigated the mechanisms underlying its specific mRNA expression in primordial germ cells (PGCs). Based on our previous findings of several microRNA miR-427 recognition elements (MREs) in the 3' untranslated region of the mRNA, we first examined whether DEADSouth mRNA was degraded by miR-427 targeting in somatic cells. Injection of antisense miR-427 oligomer and reporter mRNA for mutated MREs revealed that DEADSouth mRNA was potentially degraded in somatic cells via miR-427 targeting, but not in PGCs after the mid-blastula transition (MBT). The expression level of miR-427 was very low in PGCs, which probably resulted in the lack of miR-427-mediated degradation. In addition, the DEADSouth gene was expressed zygotically after MBT. Thus, the predominant expression of DEADSouth mRNA in the PGCs is ensured by multiple mechanisms including zygotic expression and prohibition from miR-427-mediated degradation.
编码RNA解旋酶DDX25的DEADSouth mRNA是非洲爪蟾生殖质的一个组成部分。我们研究了其在原始生殖细胞（PGC）中特异性mRNA表达的潜在机制。基于我们之前在该mRNA的3'非翻译区发现的几个微小RNA miR-427识别元件（MRE），我们首先检测了DEADSouth mRNA在体细胞中是否会因miR-427靶向作用而降解。注射反义miR-427寡聚物和针对突变MRE的报告基因mRNA表明，DEADSouth mRNA在体细胞中可能会通过miR-427靶向作用而降解，但在囊胚中期转换（MBT）后的PGC中不会。miR-427在PGC中的表达水平非常低，这可能导致缺乏miR-427介导的降解。此外，DEADSouth基因在MBT后由合子表达。因此，通过包括合子表达和阻止miR-427介导的降解在内的多种机制确保了DEADSouth mRNA在PGC中的主要表达。
