PARTICIPATION OF MICRO RNA IN THE EARLY DEVELOPMENT OF ANIMALS AND HUMANS

Abstract

Abstract. The review discussed the role of microRNA in the early stages of ontogenesis.The beginning of the third millennium was marked by a revolutionary discovery of place and role of a specific class (or classes) of small noncoding RNA (mcRNA) – varied and very common type of RNA molecules that are not involved in protein synthesis.MicroRNAs – a class of short single-stranded nucleotide sequences of regulatory RNA molecules, they are products of transcription of short noncoding proteins and genes, and are characterized by several features: small length (<200 nucleotides, mostly 21-27 nucleotides) not involved in the synthesis of proteins, links with proteins – Ago (Argonaute) family members, have typical effects of negative regulation and inhibit the expression of entire genes.Predecessor’s mcRNA are formed in the cell nucleus and then undergo modification and are transported to the cytoplasm. It is proved that they are implicated not only to the repression of transposons, but also to the regulation of embryonic development and protection of telomeres. The study of heat shock protein Hsp90 and Piwi proved the part of mcRNA in directing of embryonic development due to consistent suppression of genetic variation by using epigenetic mechanisms and inhibition of transposons activity.Human’s embryos isolated mcRNA in cultural habitat. It is shown that mcRNA-373, mcRNA-302 and others are involved in the process of differentiation of embryonic stem cells into various types of cells of three germ layers (endoderm, mesoderm and ectoderm).It is becoming increasingly clear that small noncoding RNAs play a key regulatory role in the development and functioning of the body at all stages of ontogenesis.MicroRNAs regulate gene expression at the posttranscriptional level by pairing to the specific sequences of mRNA and significantly inhibit the transmission of them.Each mcRNA can regulate hundreds of mRNAs involved in the functioning of genes of different systems (nervous, immune, endocrine etc.); genes that control the expression of other genes of signaling system of the cell cycle and so on. They are regulators of processes such as apoptosis, self-renewal of stem cells, cell differentiation and growth, ensuring the integrity of cells due silencing of genes, leading to stop translation and degradation of mRNA.