The Study Of Cloning,Expression Profile Of Yak KDM2 And Its Role In The Meiosis Of Oocyte

Yak,knows as the “plateau ship”,is a specific specie main distributed in Qinghai-Tibetan Plateau and the Alpine or subalpine regions adjacent to it in China.They are one of the main source of local residents’ economic income.With low fecundity,the calf is producted by one in two years or two in three years.Therefore,since the 1960 s,a number of studies have been conducted by scholars at home and abroad on yak reproductive physiology and reproductive technology,They found that the development and meiosis of oocyte is one of the important factors in improving the fertility of yaks.Meiosis is a common feature in all eukaryotic sexual reproduction,which regulated by many factors.Epigenetic events may ensure the appropriate expression of genes involved in meiosis,contribute to chromosome integrity and chromosome dynamics associated with meiotic progression,and prepare the genome for gene expression in the embryo.In recent study,the histone demethylase is involved in the regulation of oocyte meiosis.KDM2,one cluster of the histone demethylase family,was found to be expressed during meiosis in oocytes.However,no report has been made on the function of KDM2 in this process.In this study,we cloned the histone demethylase KDM2 A and KDM2 B gene in yak,and carried out bioinformatics analysis.The expression of KDM2 was detected by immunohistochemical analysis and q PCR.By adding the selective inhibitor of KDM2 in vitro mature medium of yak oocyte,we conducted a primary research on KDM2 and meiosis,and discussed its role in the process.Results are as follows:1、 The CDS region of KDM2 A was 3 489 bp,encoding 1 162 amino acids;the CDS region of KDM2 B was 3 930 bp,encoding 1 309 amino acids.KDM2 genes were conservative relatively in the evolutionary process,and were expressed relatively higher in spleen,uterus,testicle and ovary.2、 The immunohistochemical analysis revealed that KDM2 was present in yak oocytes and granulocytes.q PCR analysis revealed that KDM2 was dynamically changed in GV,MI and MII stages of meiosis,and the expression in MI stage is significantly higher than that in GV and MII stage.3、 We added daminozide,the specific inhibitor of KDM2,in vitro maturation of yak oocyte.When the concentration was reached to 20 μmol/L,the maturation rate of oocyte was decreased significantly,while the rate of cleavage and blastocyst after fertilization was increased significantly.While the result of q PCR and immunofluorescence showed that the expression of KDM2 in MI oocytes decreased.The present study successfully cloned the KDM2 A and KDM2 B genes in yak.KDM2 was highly expressed in the reproductive organs and dynamically expressed in the meiotic process of yak oocytes.After the addition of 20 μmol/L specific inhibitor daminozide,it can increase the cleavage rate and blastocyst rate of yak embryos,but the maturation rate of oocytes decreased.Its mechanism of action needs further study.This article provides a theoretical basis for studying the function of yak KDM2 gene and its role in physiological reproduction.