Effects Of Bovine PLAGL1 On The Proliferation And Differentiation Of Myoblasts And The Study Of Its Copy Number Variation

Chinese beef cattle are faced with the problems of low yield rate,slow growth speed and small body size.The key of solution is studying the regulation mechanism of muscle development and making full use of molecular breeding technology.Muscle development is regulated by many functional genes and non-coding RNAs.Meanwhile,some studies have shown that PLAGL1(PLAG1 like zinc finger 1)gene can affect cell proliferation and differentiation.In addition,copy number variations(CNVs)have become a new molecular marker in recent years,which can provide a new idea for breeding.Therefore,this study aims to knock down and promote the expression level of the gene.At the same time,the qPCR,Western Blot,CCK-8,EdU,flow cytometry and immunofluorescence technique were used to explore the influence of bovine myoblasts proliferation and differentiation.Then PLAGL1 gene copy number variation in Chinese beef cattle population was detected by using q PCR and SPSS correlation analysis.The main research results are as follows:1.PLAGL1 gene promotes the proliferation and differentiation of bovine myoblastsThe conserved gene in ruminants is higher and the evolutionary distance is closer,indicating that the function of this gene is similar among different species.Then the expression of PLAGL1 in different tissues during different development stages of cattle was detected.It was found that this gene was expressed in five tissues during 90 days of the embryonic period and 24 months of adult stage,which may play a wide role in the body.Besides,the gene was differentially expressed in different periods of muscle tissue.After that,PLAGL1 gene expression was artificially interfered and overexpressed.When the PLAGL1 expression was inhibited,CCK-8,EDU and flow cytometry results showed that the cell activity was weakened and the number of proliferating cells is reduced while the overexpression resulted was opposite.The expression of PCNA,CDK2 and Cyclin E1 could be significantly inhibited when the expression of this gene was down-regulated,while the expression of PCNA and CDK2 could be significantly increased when the expression of this gene was overexpressed.In terms of differentiation,when the expression of PLAGL1 is inhibited,it can interfere with the function of MyoG gene.Then overexpression will cause the enhancement of transcription and translation of MyoD and MyoG.In conclusion,PLAGL1 gene can promote the proliferation and differentiation of cattle myoblasts.2.Distribution of PLAGL1-CNV in cattle population and its correlation with phenotypic traitsThe subjects of this study included total 703 adult(24 months)cattle from six groups(Xianan cattle,Pinan cattle,Yunling cattle,Qinchuan cattle,Qiadam cattle and Guyuan cattle).Except Qinchuan cattle,in the rest of the five groups,the duplication type was the main CNV type,more than 50% of each group.And this CNV had the significant influence on body length,height at hip cross and heart girth of XN and withers height and rump length of YL(P<0.05).This study clarified the effect of PLAGL1 gene on the proliferation and differentiation of cattle myoblasts,and provided theoretical materials for the analysis of the genetic mechanism of bovine muscle formation and development.At the same time,it revealed that PLAGL1-CNV has a significant effect on some growth traits of cattle,which can be used as a potential molecular marker for beef cattle breeding.