Identification, Expression And Bioinformatic Analysis Of Microrna In Bovine FAT Tissue

MicroRNA (miRNA) are a class of small (18-24 nucleotides), endogenous and non-coding RNA which bind to target mRNA so as to regulate protein expression by repressing translation or by promoting degradation of the target mRNA or by enhancing translation at the posttranscriptional level in RNA-induced silencing complex (RISC). Growing evidence has demonstrated that miRNA play important roles during in vitro as well as in vivo adipogenesis.1. In silico prediction and characterization of microRNAs from bovine fat tissueHere we present EST (Expressed Sequence Tags)-based and GSS (Genomic Survey Sequences)-based combined approach for the detection of new miRNAs of cattle. A total of 20 new miRNAs belong to 18 miRNA families were detected following a range of filtering criteria, their functions were further predicted and analyzed. To confirm our prediction, a miRNA-detecting microarray was designed with probes complementary to previously known mature miRNA sequences from 131 organisms. Providentially, all the 18 predicted miRNA familys were identified by the microarray, though the expression signal values were at low levels. We use the TargetScan to predict the target mRNA and the major GO term of potential targets was calculated using the DAVID bioinformatics resources to gain further insight into biological function of newly identified bovine miRNAs. These potential miRNA targets belong to agreat many of gene families which play various roles during physiological and pathological processes. Taken together, our results expand the number of known bovine miRNAs.2. MicroRNA expression profiles of beef cattle intramuscular fat and subcutaneous fatMicroRNAs (miRNAs) are endogenous non-coding RNA that has been proposed play important roles in the formation of body fat. However, the differential expression of miRNA and the role of these miRNA in bovine intramuscular and subcutaneous fat tissue are still unknown. In this study, profile of differentially expressed miRNA and the target gene analysis in intramuscular adipose and subcutaneous adipose of adult beef cattle were investigated by microarray and bioinformatic. The data identified 88 differentially expressed miRNAs in 213 miRNAs which were detected on the microarray, and 30 miRNAs among these 88 miRNAs were changed significantly between intramuscular and subcutaneous fat (fold change>1, P<0.001). miR-143, miR-145, miR-26a, miR-2373-5p and miR-23b-3p were highly expressed in intramuscular fat, whilst miR-26a, miR-2373-5p, miR-2325c, miR-3613 and miR-2361 showed highest abundance in subcutaneous fat. Bioinformatics of KEGG pathway analysis and GO term enrichment suggested that these differentially expressed miRNAs involved in different pathway and target genes which may differently regulate the fat deposition. Taken together, our studies provides the first evidence for better understanding the differential expression and mechanisms of miRNA in bovine fat deposition, and provide thinking to improve quality of beef by reducing subcutaneous fat and increasing intramuscular fat of beef cattle.3. Interaction network of miR-143/145 cluster target geneIn order to explore the role of miR-143/145 cluster in the growth and development process and its regulatory mechanism in intramuscular fat, the profiling of miR-143 and miR-145 and the signal pathway network of target genes were analyzed. Microarray of bovine microRNA and qRT-PCR were employed to detect the miR-143 and miR-45 between intramuscular adipose tissue and subcutaneous adipose tissue. Targetscan algorithm was used to predict target gene of miR-143 and miR-145, and the result of gene set was analyzed by bioinformatic of GO annotations, GO term enrichment and KEGG enrichment methods, Pathway network was build in the last. It was revealed that a total of 575 putative target sites for miR-143/145 cluster in bovine were identified. The results of bioinformatic indicated that 21 target genes of miR-143 and miR-145 are mostly enrichment in MAPK pathway, and genes of TGFB2?TGFBR2?TNF?MYC are both in MAPK pathway and TGF-beta signaling pathway. CD 14 is the common target of miR-143 and miR-145 in MAPK pathway. miR-143/145 cluster may play important roles by distinct pathway such as MAPK pathway in bovine intramuscular adipogenesis.