Submitted to: Society for the Study of Reproduction Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/18/2009
Publication Date: 7/18/2009
Citation: Zhang, X., Xiao, C., Salem, M., Rexroad Iii, C.E., Yao, J. 2009. Cloning of oocyte-expressed MicroRNAs in rainbow trout (Oncorhynchus mykiss). Society for the Study of Reproduction Annual Meeting. Interpretive Summary:
Technical Abstract: MicroRNAs (miRNAs) are a class of endogenous small non-coding RNA molecules that regulate post-transcriptional expression of target genes and play important roles in animal development. We report here the identification of rainbow trout oocyte-expressed miRNAs and their expression profiles during ovarian development. A miRNA library was constructed using small RNAs isolated from mature unfertilized rainbow trout oocytes and 2,400 clones were sequenced. Sequence analysis identified 30 distinct miRNAs, of which 18 are known rainbow trout miRNAs that have been previously described. The remaining 12 miRNAs include 4 new miRNAs that are homologous to miRNAs from other species in the miRBase, and 8 potentially novel miRNAs that do not match any known miRNAs in the miRBase. Analysis of tissue distribution of these new and novel miRNAs using quantitative real time PCR identified 2 miRNAs (miRNA-451 and a novel miRNA) that are expressed predominantly in mature oocytes. In addition, 3 novel miRNAs showed very high expression in mature oocytes although they are also expressed in multiple somatic tissues. These 5 miRNAs were further analyzed for their expression during ovarian development. While many of them display dynamic expression patterns during different stages of development, miRNA-451 appears to be highly abundant in late vitellogenic oocytes, suggesting a role of this miRNA for early embryonic development. Computational prediction of the target genes of these miRNAs abundantly expressed in oocytes identified genes that might function in the physiological processes of development. Further analysis of expression signatures of these oocyte-expressed miRNAs and understanding their roles in controlling ovarian folliculogenesis and early embryogenesis may ultimately lead to the development of molecular markers for rainbow trout egg quality and embryonic development potential.