Identification Of SNPs Of Chicken Myoz1 Gene And Its Role In Muscle Atrophy

Myoz1 gene in mammal can simultaneously regulate the type and diameter of skeletal muscle fibers under the premise of healthy development of animal.The type and diameter of skeletal muscle fibers are the key factors determining the meat quality and yield of livestock.Therefore,Myoz1 gene has high research value,but there has been no report on Myoz1 gene in poultry.The polymorphisms information of Myoz1 gene exon in Avian and Yellow Bantam chicken was were obtained by direct sequencing,and their correlation between carcass traits was analyzed to explore the similarities or differences of Myoz1 gene function between chicken and mammal.Then,the method of gene expression quantification,gene interference and overexpression was used to further explore the role of Myoz1 gene in the early development of skeletal muscle in chicken.The main results are as follows:(1)Five single nucleotide polymorphisms(SNPs)were detected in exons of Myoz1 gene,including three missense mutation SNPs(SNP1: g.16022512G>T,Aal 103 Ser;SNP3: g.16022560C>T,His 119 Tyr and SNP5: g.16023903 A>G,Ser 189 Gly)and two synonymous mutation SNPs(SNP2: g.16022529T>C and SNP4: g.16023878A>C),and all detected SNPs existed in both Avian and Yellow Bantam chicken.The results of correlation analysis showed that SNP2,SNP3,SNP5 in Yellow Bantam chicken and SNP3,SNP4 and SNP5 in Avian were significantly association with certain traits(P < 0.05),and most of the traits significantly affected by SNP in exon region of Myoz1 gene were muscular and skeleton traits.(2)The expression of Myoz1 gene in pectoral and leg muscle during the period from E10 to D7 was detected by qPCR.It was found that the expression of Myoz1 gene was clearly detected in the pectoral and leg muscle from E14.In pectoral muscle,the expression of Myoz1 gene increased from E14 to E19,and then decreased from E19 to D3,and increased again after D3.In leg muscle,the expression of Myoz1 gene increased continuously with time.In addition,the expression level of Myoz1 gene in the pectoral muscle and leg muscle at the same time point were compared,it was found that the expression level of Myoz1 gene in the pectoral muscle were significantly higher than that in leg muscle at the E18 and E19(P<0.05),and the expression level of Myoz1 gene in the leg muscle was significantly higher than that in pectoral muscle(P<0.05).At other time points,there was no significant difference in the expression of Myoz1 gene between pectoral and leg muscle(P>0.05).(3)The expression of MuRF1 and Atrogin-1 gene in pectoral and leg muscle during embryonic development and early posthatch was detected by qPCR to track the occurrence of breast muscle atrophy.It was found that the expression of MuRF1 in pectoral muscle on E19 and E20 was significantly higher than other time points(P < 0.05),and the expression of Atrogin-1 in pectoral muscle on E20 and D1 was significantly higher than other time points(P < 0.05).Quantitative results of two genes in pectoral muscle showed that atrophy of pectoral muscle occurred around E20.The expression of MuRF1 and Atrogin-1 in leg muscle was used as a reference to further determine the occurrence of muscle atrophy in pectoral muscle.It was found that the expression of MuRF1 in the pectoral muscle was significantly higher than that in leg muscle during E17-D2(P<0.05).),and the difference between E19 and E20 was extremely significant(P<0.01);while the expression of Atrogin-1 in pectoral muscle and leg muscle was no significant difference at E20,D1(P>0.05),indicating that the MuRF1 gene is more suitable than the Atrogin-1 gene as a marker for pectoral muscle atrophy during chick embryo development.The muscle atrophy of the pectoral muscle marked with the MuRF1 gene occurred in E17-D2,and the muscle atrophy occurred most severely in E19-E20.(4)Interference or overexpression Myoz1 and MuRF1 gene in skeletal muscle satellite cells,respectively,found that interference with MuRF1 gene significantly reduced the expression of Myoz1 gene in cells(P<0.05),and overexpression of MuRF1 gene significantly increased the expression of Myoz1 gene in cells(P < 0.05),while the interference or overexpression of Myoz1 gene had no significant effect on the expression of MuRF1 gene.Therefore,there was an expression regulation relationship between Myoz1 gene and MuRF1 gene.In this study,we found that Myoz1 gene mainly affects muscle-related traits and is functionally consistent with mammals.In addition,we found that Myoz1 gene expression is regulated by a muscle atrophy key gene MuRF1.Therefore,the change of MuRF1 gene expression during pectoral muscle atrophy results in the differential expression of Myoz1 gene in pectoral muscle and leg muscle during the same period.Therefore,the Myoz1 gene,which has the function of regulating muscle fiber diameter,may be involved in the pectoral muscle atrophy during embryonic development.