Jinfeng Liu, Yanhong Cao, Zhuyue Wu, Laiba Shafique, Shaomei Chen, Zeyi Xuan, Tong Feng, Chan Luo, Peng Zhu*,and Qingyou Liu

Abstract The Gene Growth Differentiation Factor 9 (GDF9) is far most important gene for oogenesis. Few studies have been reported concerning buffalo oogenesis and embryogenesis. In current study, complete coding region of a gene of the buffalo GDF9 gene was cloned and sequenced, which was found to have 1,362 nucleotides long encoding of 453 amino acid proteins. The expression pattern analysis results showed that GDF9 existed spanning the entire stage of folliculogenesis and embryogenesis. The GDF9 gene increased in the initial stage then decreased during follicular development. The gene was significantly higher in the Cumulus-Oocyte-Complexes (COC) of small and middle diameter follicles compared to large follicles. Its expression level was significantly higher in embryogenesis rather than folliculogenesis except the blastula stage. Immunohistochemistry showed that the GDF9 protein was found in testis and in follicles of oocytes including primordial granulose cells, primary, secondary and antral follicles, and also in theca cells. The study of the GDF9 gene provided an important base knowledge for further study regulation mechanism of GDF9 gene in buffalo oogenesis.

Keywords: Buffalo; GDF9; Expression pattern; Oogenesis