Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
Curr Biol. 2017 Apr 3;27(7):1062-1067. doi: 10.1016/j.cub.2017.02.040. Epub 2017 Mar 23.
Maternally inherited noncoding RNAs (ncRNAs) can regulate zygotic gene expression across generations [1-4]. Recently, many stable intronic sequence RNAs (sisRNAs), which are byproducts of pre-mRNA splicing, were found to be maternally deposited and persist till zygotic transcription in Xenopus and Drosophila [5-7]. In various organisms, sisRNAs can be in linear or circular conformations, and they have been suggested to regulate host gene expression [5-10]. It is unknown whether maternally deposited sisRNAs can regulate zygotic gene expression in the embryos. Here, we show that a maternally inherited sisRNA (sisR-4) from the deadpan locus is important for embryonic development in Drosophila. Mothers, but not fathers, mutant for sisR-4 produce embryos that fail to hatch. During embryogenesis, sisR-4 promotes transcription of its host gene (deadpan), which is essential for development. Interestingly, sisR-4 functions by activating an enhancer present in the intron where sisR-4 is encoded. We propose that a maternal sisRNA triggers expression of its host gene via a positive feedback loop during embryogenesis.
母系遗传的非编码 RNA（ncRNAs）可以跨代调节合子基因表达[1-4]。最近，许多稳定的内含子序列 RNA（sisRNAs），作为前体 mRNA 剪接的副产物，被发现被母体沉积并在 Xenopus 和 Drosophila 中持续到合子转录[5-7]。在各种生物体中，sisRNAs 可以呈线性或环状构象，并且它们被认为可以调节宿主基因表达[5-10]。尚不清楚母体沉积的 sisRNAs 是否可以调节胚胎中的合子基因表达。在这里，我们表明来自 deadpan 基因座的母系遗传 sisRNA（sisR-4）对果蝇胚胎发育很重要。突变 sisR-4 的母体会产生无法孵化的胚胎。在胚胎发生过程中，sisR-4 促进其宿主基因（deadpan）的转录，这对发育是必不可少的。有趣的是，sisR-4 通过激活其编码内含子中的增强子发挥作用。我们提出，母系 sisRNA 在胚胎发生过程中通过正反馈环触发其宿主基因的表达。
