Expression Of YAP1 Gene And Association Analysis Of The Polymorphism With Egg Production Traits In Chicken Ovary

YAP1(Yes-associated protein 1),a cell junction protein and transcription coactivator was first discovered by the Sudol in 1994,but YAP1 was originally discovered in Drosophila,the another name Yri;YAP1 gene located in chicken chromosome 1,containing 7 exons,The YAP1 protein molecule it encodes is composed of 448 amino acids,which is a proline 65 kDa rich in phosphor,also known as YAP65 factor.YAP1 has the function that promoting cell division and proliferation and is an important cell growth factor in organisms.Recent studies have shown that YAP1 has high expression levels in the human ovary and its excessive proliferation leads to ovarian cancer.Because the YAP1 gene has a great correlation with many cancers,so it is also called proto-oncogene.One of them is that the participation of Hippo / MST signaling pathway in network regulation plays an important role in cell proliferation.In this study,Hy-Line brown layers at 150 day and Zhuanghe Dagu chicken were used as test objects.Semi-quantitative RT-PCR and immunohistochemical techniques were used to detect the temporal and spatial expression pattern of mRNA and protein expression of YAP1 in chicken follicular growth.In the assay,the YAP1 gene was used to screen related SNP using PCR-SSCP.The main results of the study are as following:Experiment first,semi quantitative RT-PCR results showed that YAP1 gene expressed in the chicken ovary matrix,former differentiation of follicles,and differentiated follicles of Hy-Line brown layers at 150 Day,but no significant difference between the expression level(P>0.05).The results showed that the relative expression abundance of mRNA in both the pre-hierarchical and the differentiated follicles maintained a stable level,presenting the constitutive expression characteristic of YAP1 gene.The results suggest that a relatively stable expression of YAP1 gene mRNA may be necessary for maintaining normal growth and development of follicles at various stages of follicular development in chicken and is one of the important factors regulating the normal growth and development of follicles at all levels in the ovarian tissue.Experiment two,chicken YAP1 protein molecules are mainly expressed in ovarian stroma tissue,pre-grade follicular oocytes,and granulosa cells,but no expression signal was detected in membrane cells.In the early stage of follicular development,brown positive signals were detected in oocytes and stromal cells.As before the follicular development oocytes was increasing largely,layer cells and granular cells gradually proliferated,layer and granule cell layer became thicker,strong positive signals were detected in oocytes and granulosa cells,but no positive signal was detected in membrane cells.The results suggest that YAP1 protein is expressed mainly in oocytes and granulosa cells,and probably is not expressed or weakly expressed in the membrane cells(but the positive signal can not be detected by immunohistochemistry).The result indicates that YAP1 molecules may play a local regulatory role mainly at autocrine or paracrine manner in the follicles during growth and development.The experiment results provide reference for the further study on the specific regulation and molecular mechanism of YAP1 molecules in different follicle growth and development stages.Experiment three,Correlation analysis with egg production traits by using PCR-SSCP showed that G2964 A base mutation was detected in exon 2 of the YAP1 gene.According to the SNP locus,360 Dagu chickens were divided into three genotypes: AA,AG and GG.The frequency of allele G was higher than that of allele A,and the frequency of AG genotype was higher than that of genotypes AA and GG.For hen egg production traits the AA type in 30,43,57,66 week old egg production was significantly higher than that of AG and GG(P<0.05),and AG was not significant in 30,43 week old egg production with the GG type difference(P>0.05),type AG in the 57,66 week old egg production was significantly higher than that of GG(P<0.05),the proportion of additive genetic variation at the SNP locus for the four egg production traits was also relatively high.The results can provide a molecular basis for the selection of new potential molecular markers for the selection of marker assisted breeding for raising the egg laying performance as the main breeding target.