The Expression Pattern Identification Of Genes And Mirnas In Beijing Duck’s Embryonic Breast Muscle And Their Relationship

The lean line of Z-type Beijing duck with higher lean meat ratio and higher feed conversion efficiency was successfully bred based on the initial Beijing duck. The lean line of Beijing duck can meet different consumer demand and can provide an ideal animal model for the exploration of skeletal muscle development mechanism. The formation of phenotype is the interaction results of genes and environment, the genes are genetic basis of the phenotype formation. Therefore, the isolation and identification of genes controlled the related trait and mi RNAs regulated the above genes are an effective way in exploration of the mechanism of skeletal muscle development.Based on the fact above, we identified the expression patterns and characteristics of the genes and mi RNAs in embryonic breast muscle of Beijing duck and their relationship between the identified genes and mi RNAs above by using high throughput sequencing and bioinformatics technology analysis. In addition, the effect of some novel mi RNAs predicted through our mi RNAs sequencing data on the differentiation of myogenesis was explored usng overexpression and RNAi technology. The results were listed as follow.(1) E19 is the fastest point of breast muscle development and that E19 is also the crucial transition for Pekin duck pectoral muscle development during embryonic stage.(2) The analysis of differentially expressed genes in embryonic breast muscle of Beijing duck and the KEGG pathway analysis of these genes showed that there were huge difference between the breast muscle development state of E27 and that of E13 and E19. There was an initial regulation for fat and fat-soluble substance in E13 breast muscle of Beijing duck, the related pathways of fat development were significantly enriched in E19 breast muscle of Beijing duck, and the related pathways of metabolism were dominant in E27 breast muscle of Beijing duck.(3) Totally, 359 known mi RNAs and 23 novel mi RNAs were identified in E13, E19 and E27 breast muscle of Beijing duck. The expression patterns of 15 muscle-related known mi RNAs, whose expression were validated by using q RT-PCR, can be divided into three types: the mi RNAs with their expression increasing from E11 to E27, the mi RNAs with their expression reached to the bottom at E19 and the mi RNAs with their expression peaked at E19. Among the 23 novel mi RNAs, only novel-mir-8 and novel-mir-14 highly expressed in embryonic breast muscle of Beijing duck, and the subsequent functional validation study indicated that novel-mir-8 was a potential inhibitor and novel-mir-14 was a potential promotor.(4) The significantly association analysis between mi RNAs and m RNA were carried out. In group of E13-E19, 43 differetially expressed mi RNAs and 22 differetially expressed m RNAs were surported each other and the 22 differetially expressed m RNAs were mainly associated with the myogenesis, development and differentiation of skeletal muscle. In group of E19-E27, 48 differetially expressed mi RNAs and 141 differetially expressed m RNA were surported each other. The differetially expressed genes above were involved in DNA replication, myogenic, muscle development and cell cycle biological processes.(5) The functional exploration of novel-mi R-6, novel-mi R-17 and novel-mi R-20 on the myogenesis differentiation of myoblasts cell was performed by using overexpression and inference technology. The results showed that novel-mi R-17 and novel-mi R-20 were both the inhibitors of myogenesis differentiation of myoblasts cell, but the function of novel-mi R-6 was not clear.The results of this research could provide a method to explore the mechanism of embryonic breast muscle development of Beijing duck from genes and mi RNAs level, could provide theoretical basis and foundation for molecular breeding of Beijing duck, and could also provide a model for the study of skeletal muscle development of other animals.