Abstract:

MicroRNAs (miRNAs) are a class of small noncoding RNAs of 21~22 nucleotides in length that play important roles in multiple biological and developmental processes by degrading targeted mRNAs or repressing mRNA translation. The database of miRBase16.0 (2010) show that there are 175, 673, 408, and 1048 annotated miRNAs for Caenorhabditis elegans, Mus musculus, Rattus norvegicus, and Homo sapiens, respectively. However, there are only 211 miRNAs described for Sus scrofa. In particular, the miRNAs which regulate gene expression in embryonic growth and development are still poorly understood. Therefore, in this study we carried out poly(A)-tailed RT-PCR to verify the expression of ten miRNAs at porcine embryonic day 33 (E33). Of these distinct miRNAs identified, we determined the relative amount of miRNAs by quantitative real-time PCR and performed investigation into identification of the potential target mRNAs using PicTar and TargetScan. Results showed that: ssc-miR-9 is the most abundantly expressed miRNA in the head region, ssc-miR-1 is the most abundantly expressed miRNA in the organ region. Function analysis suggested that these miRNAs are mostly involved in the development of nerves, the cerebrum, muscle, and organs. Our results provide useful information for the investigation of embryonic miRNAs in the pig and other animals.