Advance in research of characteristics and action mechanism of microRNAs from prokaryotes / 中国人兽共患病学报

ABSTRACT

microRNAs is a group of small non-coding RNAs that play a negative regulation role in expression of target genes at post-transcriptional level by inhibition or degradation of target mRNAs after combination of the seed sequence (SS) in microRNAs with the SS-binding sequences usually located at 5'ends of target mRNAs.microRNAs was firstly found in Caenorhabditis elegans.Subsequently,many different microRNAs in eukaryocytes were revealed.In eukaryocytes,microRNA precursors are transcribed at first and then become functional microRNAs with 21-23 nt in size after splice.Most of eukaryocytic microRNAs combime with the sequences at 3'end of target mRNAs that cause the translation inhibition or degradation of the mRNAs.In the recent years,many different prokaryocytes,such as bacteria,have been confirmed to possess microRNAs.However,the microRNAs in prokaryotes such as bacteria are 50-400 nt in size and have the biological activity without splice.Moreover,the characteristics,action sites and mechanisms of the prokaryotic microRNAs have some certain diversity compared to the eukaryotic microRNAs.Our review briefly introduce the major regulation mechanisms of gene expression as well as the general characteristics of microRNAs and their regulation mechanisms of gene expression in prokaryocytes and eukaryocytes,which will provide a basis for further and profound study on the gene expression regulation and pathogenic mechanisms of prokaryotic microbial pathogens.