トラフグ小分子RNAの網羅的解析

1.研究目的在许多生物中对miRNAs的深入研究表明，miRNAs参与了各种生物现象，但与人和小鼠相比，对鱼类miRNAs的研究一直很少。红鳍金枪鱼(Torafugu)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物种之一。Torafhgu的基因组仅比人类基因组小约8倍，但具有相似的蛋白质编码基因谱系。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个组织(快肌、慢肌、心、眼、脑、肠、肝、卵巢和睾丸)中全面鉴定torafugu miRNA，以了解特定的miRNAs如何调控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个已知的miRNA物种，其中约2000个miRNA物种尚未在鱼类中被鉴定，但在其他物种中已被报道。此外，我们还发现约有40种miRNAs是鱼类特有的。许多已知的miRNAs在特定组织中有强表达。这些已知miRNAs的表达模式与以前报道的在其他动物中的表达模式相似。MiRNAs主要在卵巢和睾丸以外的组织中表达。然而，一些miRNA家族在性腺中高度丰富，但在体细胞中表达较少，提示它们在生殖系细胞中具有特定的功能。在性腺中丰富的较长的小RNA(26-28nt)可能是推测的piRNA。此外，数据还可能包括许多假定的miRNAs、esiRNAs和大量未分配的小RNAs。

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.