The High Throughput Screening of Direct Regulatory microRNA and Their Target Genes

53 new microRNAs which have p53-DNA binding sites and regulated the p53 upstream transcription factor and downstream target genes were screened from 676 human microRNAs. The microRNAs and p53 protein interaction networks was constructed through mined the known interaction of p53 and p53-microRNAs. Remarkably, FAS was found, which is a key factor in the apoptotic pathway regulated by a number of microRNAs. The interaction of FAS-microRNAs maybe play a key role in the apoptotic pathway. A presumptive p53-microRNA regulatory mechanism was proposed: p53 as a transcription factor regulated the target genes and direct regulatory microRNAs, whereas it also is regulated by upstream transcription factor and microRNAs. So, a balance which p53 located in the center would be formed by the factors of p53 pathway, the disease would be caused when this balance is broken. A total of 15 500 genes were predicted as targets of these 53 microRNAs and they are classed by 27 clusters according to the frequency of gene in all the 15 500 genes. Function annotation analysis of genes frequency more than 10 revealed a novel p53 functions, including cell adhesion and migration which suggested that p53 can suppress metastasis through direct transcriptional regulation of this new category of molecular targets. 30 microRNAs which involved in cell cycle, apoptosis and cell proliferation were explored through gene functional enrichment analysis, noticeably, 9/30 microRNAs (hsa-mir-181a-1, hsa-mir-181b-1, hsa-mir-181c, hsa-mir-181d, hsa-mir-195, hsa-mir-497, hsa-mir-495, hsa-mir-543 and hsa-mir-548c) regulated all three biological process, which implies that these 9 microRNAs maybe play a key role in the regulation of p53 signaling pathway and feedback loops through interaction of microRNAs. Finally, the homology and conservation of 30 microRNAs were analyzed in the 36 species and 10 new highly conserved microRNAs (hsa-mir-497, hsa-mir-495, hsa-mir-543, hsa-mir-19a, hsa-mir-19b-1, hsa-mir-200b, hsa-mir-448, hsa-mir-28, hsa-mir-455 and hsa-mir-590) which have not included in the current microRNA database yet were found.