MicroRNA evolution, expression, and function during short germband development in Tribolium castaneum.
MicroRNA evolution, expression, and function during short germband development in Tribolium castaneum.
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DOI：
10.1101/gr.193367.115
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发表时间：
2016-01
期刊：
影响因子：
7
通讯作者：
Griffiths-Jones S
中科院分区：
文献类型：
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作者：
Ninova M;Ronshaugen M;Griffiths-Jones S
MicroRNA是多细胞动物发育中公认的参与者。我们对microRNA在节肢动物发育中的功能的理解大多来自果蝇的研究。尽管它们作为模式系统的优势，果蝇的长胚带胚胎发生是一个进化衍生的状态，仅限于几个全变态昆虫谱系。microRNA的进化和表达在动物的发展表现出祖先和更广泛的短胚带模式的胚胎发育尚未被表征。我们测序的小RNA文库的卵母细胞和连续的时间间隔，涵盖胚胎发育的短胚带模式生物，赤拟谷盗。我们分析了microRNA互补序列的进化和时间表达，并对总RNA文库进行了测序，以研究与microRNA靶表达的关系。我们显示microRNA母体加载和序列特异性3′端非模板寡腺苷酸化的母体沉积microRNA之间的Tribolium和果蝇的保守。我们进一步揭示了编码多个旁系同源物的大簇，这些旁系同源物来自几个赤拟谷盗特异性microRNA家族，这些家族在合子转录激活后立即在一个狭窄的时间间隔内表达。这些新的microRNA，与几个早期表达的保守microRNA一起，靶向大量的母体沉积的转录本。与果蝇的比较表明，microRNA介导的母体转录物靶向在昆虫中是一个保守的过程，但所涉及的microRNA的数量和序列已经出现分歧。快速进化和种特异性microRNA在T. castaneum的研究结果与之前在果蝇中的发现一致，并表明在这个阶段对microRNA创新的独特宽容是一种保守的现象。
MicroRNAs are well-established players in the development of multicellular animals. Most of our understanding of microRNA function in arthropod development comes from studies in Drosophila. Despite their advantages as model systems, the long germband embryogenesis of fruit flies is an evolutionary derived state restricted to several holometabolous insect lineages. MicroRNA evolution and expression across development in animals exhibiting the ancestral and more widespread short germband mode of embryogenesis has not been characterized. We sequenced small RNA libraries of oocytes and successive intervals covering the embryonic development of the short germband model organism, Tribolium castaneum. We analyzed the evolution and temporal expression of the microRNA complement and sequenced libraries of total RNA to investigate the relationships with microRNA target expression. We show microRNA maternal loading and sequence-specific 3′ end nontemplate oligoadenylation of maternally deposited microRNAs that is conserved between Tribolium and Drosophila. We further uncover large clusters encoding multiple paralogs from several Tribolium-specific microRNA families expressed during a narrow interval of time immediately after the activation of zygotic transcription. These novel microRNAs, together with several early expressed conserved microRNAs, target a significant number of maternally deposited transcripts. Comparison with Drosophila shows that microRNA-mediated maternal transcript targeting is a conserved process in insects, but the number and sequences of microRNAs involved have diverged. The expression of fast-evolving and species-specific microRNAs in the early blastoderm of T. castaneum is consistent with previous findings in Drosophila and shows that the unique permissiveness for microRNA innovation at this stage is a conserved phenomenon.