Study Of The Expression Of MICRORNA-770 During Mouse Embryonic Development

MicroRNAs are a recently characterized class of small, non-coding RNAs that modulate the translation or stability of a target mRNA through interaction with its 3′untranslated region (UTR). Hundreds of miRNAs have been identified from animals. MicroRNAs have been proved to play essential roles in diverse biological processes. To investigate the expression and function of miR-770 during mid-later-gestation mouse embryogenesis, we employ imprinting analysis and in situ hybridization to research the imprinted state and the location of miR-770 in developing mouse embryos.Conservatism analysis showed that miR-770s and their hairpin precursors were highly conversed in high mammals, as Homo sapiens, Rattus norvegicus, Mus musculus, Pan troglodytes, Pongo pygmaeus, Macaca mulatta, and Equus caballus. Semi-quantity RT-PCR indicated that miR-770 expressed continuously from E10.5 to E18.5 in whole mouse embryos. And the highest relative expression was observed in E16.5 embryo. In further, miR-770 had different expression levels in different tissues. In E15.5 and E18.5 embryos, miR-770 was highly expressed in the brain, tongue, and lung. During the postnatal period, miR-770 was expressed specially in the brain. Imprinting analysis indicates that miR-770 was imprinted in these tissues in E15.5 and E18.5 embryos between DBA and C57BL/6J. In situ hybridization showed that the location of the mature miR-770 was dynimic and highly tissue-specification. In E10.5 and E11.5 embryos, the signals of miR-770 were obviously in brain, somite and limbs. In E15.5 and E16.5 embryos, the signals of mature miR-770 were specificly detected in skeleton. These results indicated that miR-770 was a new imprinted microRNA, and it would be an important regulator for the development of skeleton.