トラフグ小分子RNAの網羅的解析

1.研究目的miRNAs在许多生物体中的深入研究表明，miRNAs参与了多种生物学现象，但相对于人和小鼠而言，鱼类miRNAs的研究较少.红鳍东方鲀（Takifugu rubripes）是另一种已知基因组序列的模式生物，也是研究最深入的鱼类之一。托拉夫古基因组的大小仅为人类基因组的八分之一左右，但其蛋白质编码基因库相似，因此，它也可能有助于揭示包括miRNA基因在内的非编码基因.研究实施计划我们计划在9种组织（快肌和慢肌、心脏、眼、脑、肠、肝、卵巢和睾丸）中全面鉴定Torafugu miRNA，以了解特定miRNA如何调节鱼类各器官的基因表达，并阐明其生物学功能.结果我们发现了约9000种已知的miRNA，其中约2000种在鱼类中尚未发现，但在其他物种中已报道。此外，我们发现大约40种miRNAs具有鱼类特异性。许多已知的miRNAs在特定组织中表现出强表达。这些已知的miRNAs的表达模式与以前在其他动物中的报道相似。大部分miRNAs主要在卵巢和睾丸以外的组织中表达。然而，一些miRNA家族在生殖腺中含量较高，但在体细胞中表达量较低，提示它们在生殖细胞中具有特异性功能，而在生殖腺中含量较高的26-28 nt的小RNA可能是推测的piRNA。此外，数据还可能包括许多推定的miRNA、esiRNA和大量未分配的小RNA。

1. Purpose ofresearchIntensive stUdies of miRNAs in many organisms have revealed that the miRNAs were involved in various biological phenomena.However researches of fish miRNAs have been poorly addressed compare with human and mouse. TorafUgu (Takifugu rubripes), is another model organism withknown genome sequence and one ofthe most intensively studied fish species. The genome of the torafhgu is only about eight times smaller than human genome in size, but has a similar repertoire of protein coding genes.Therefore, it may also be useful for unveiling non-coding genes including miRNA genes.2. Research Implementation PlanWe plan to fully identify torafugu miRNA in 9 tissues (Fast and slow muscles, heart, eye, brain, intestine, liver, ovary and testis) in order to understand how specific miRNAs regulate gene expression in the various organs of fish and elucidate their biological function.3. ResultWe found about 9000 known miRNA species, About 2000 miRNA species have not yet been identified in fish but already reported in other species. Moreover, we found about 40 miRNAs species were fish specific. Many known miRNAs showed strong expression in specific tissues. These expression patterns of the known miRNAs were similar with those of previous reports in other animals. Most of miRNAs were mainly expressed in tissues other than ovary and testis. However, some miRNA families were highly abundant in gonads but slightly expressed in somatic tissues, suggesting their specific functions in germ line cell.Longer small RNAs (26-28 nt) which are abundant in gonads may be putative piRNAs. In addition, the data may also included many putative miRNAs, esiRNAs and a large number of unassigned small RNAs.