The Role Of MicroRNAs In Avoidance Behavior Of Caenorhabditis Elegans

microRNA(miRNA) are endogenous noncoding ribonucleic acids that the Length is about20to24nt. miRNA mainly through two different ways to control gene expression:First miRNA in completely complementary way to conmbine with its corresponding target mRNA to degrade mRNA of target gene. Second miRNA pairs to sites within the3’untranslated region (3’UTR) of target mRNAs, can influence mRNA translation.All of these suggest that miRNA play critical roles in the regulation of gene expression at the transcriptional or posttranscriptional level.In the nematode C.elegans, miRNA regulate biological processes such as development, life.The before experiment had determined the miRNA expression profiles in worms exposed to pathogenic bacteria Pseudomonas aeruginosa PA14by using RNA deep sequencing and proteomic approach iTRAQ.Compared with standard food E. coli OP50, some miRNA and miRNA families expression and protein levels were upregulated or downregulated.we tested56available mutant strains of these71miRNA that these miRNA and miRNA families were upregulated.The results show that mutations in most miRNA did not influence avoidance behavior, mir-53、mir-67、 mir-86mutants escape capacity decrease obviously, compared with N2the ability to escape decline about40%.Its sugget that the three miRNA play a positive role in C.elegans avoidance behavior. Three authority miRNA target prediction algorithms (Pictar,MICRORNA, and TargetScan) indicate that there are24target genes of mir-53/55target genes of mir-67/63target genes of mir-86. Because miRNA influence mRNA translation by pairing to sites within the3’untranslated region (3’UTR) of target mRNAs.Therefore, we overlap downregulated-protein encoding genes and the predicted target genes,we found mir-67has two overlapping genes that is rpl-33at8h and sax-7at12h. Further escape experiment found that sax-7RNAi worm’s escape ability to get a degree of recovery compared with mir-67mutant strains, it shows sax-7rather than rpl-33play a negative role in C.elegans avoidance behavior. Through the Known and Predicted Protein-Protein Interactions network (http://string-db.org/), we found proteins that interact with the sax-7. RNAi experiments in worms show that there is no genes affect the avoidance behavior, that is to say we didn’t find downstream gene of sax-7. So we are looking for transcription factors and upstream pathway involved in avoidance behavior, we find gene GEI-11that change the mir-67expression.According to the above, during P. aeruginosa PA14infection, transcription factor GEI-11may be suppressed, GEI-11negative control ability of mir-67expression is reduced, which in turn leads to enhance its effect on the degradation of target gene sax-7., ultimately promoting the avoidance behavior to P. aeruginosa PA14.