Abstract

The interaction of 784 intergenic (ig-miRNA), 686 intronic (in-miRNA) and 49 exonic miRNAs (ex-miRNA) with mRNAs of 51 oncogenes coding in-miRNAs wasinvestigated. Out of the studied genes, 44 were targets for 94 ig-miRNAs, 29 were targets for 44 in-miRNAs and 7 were targets for 7 ex-miRNAs. The density of miRNA binding sites was higher in 5'-untranslated regions than it was in coding sequences and 3'-untranslated regions. Three types of miRNA interaction with mRNA were revealed: 5'-dominant canonical, 3'-compensatory and complementary types. In-miRNAs do not interact with mRNAs of host genes (where in-miRNA is encoded). Linkage between some mRNAs of genes encodes in-miRNAs via other in-miRNAs was revealed. These data promote the understanding of interaction mechanism of miRNA with mRNA genes participating in gastrointestinal and breast cancers.

Key words: Intergenic miRNA, intronic miRNA, exonic miRNA, mRNA, 5'-untranslated region, coding sequences, 3'-untranslated region, human, oncogene.