| NOTCH pathway can regulate cell proliferation, differentiation and apoptosis through direct action between adjacent cells, which determine the differentiation and development of cellsã€tissues and organs. As one of the most important receptor genes of Notch signaling pathway, Notch2 plays an important role in mammalian tumorigenesis, organ formation and follicular development. In 2001, Joshua first discovered Notch2 expressed in mammalian mouse ovaries, subsequent study found that Notch2 has great associations with the formation of primordial follicle cell proliferationã€cavity granulosa cell proliferation and oocyte development. However, the research of Notch2 gene has not involved in large mammals economic animals, the objective of this study was to explore Notch2 gene expression in sheep ovary follicle. Partial sequence of Notch2 gene was cloned and sequenced for the first time in the sheep ovary, and the homology alignment between the cloned sequence and that of other species was done using the software of DNAMAN; The mRNA expression of Notch2 and related genes Hesl and c-myc in granulasa cells and membrane cells of sheep follicles in different sizes were analyzed by real-time PCR to study the expression pattern and explore the influence of Notch2 in sheep follicle development; Notch2 protein expression and location in sheep ovaries were examed by immunohistochemical technique, the main experiment results and analysis are as follows:Found Notch2 gene was expressed in sheep ovary by using RT-PCR, and gained part sequence:527bp. Compared with antelope, goat and cow, it showed that there was high homology among them by DNAMAN software.The real-time PCR results showed that the expression of Notch2 mRNA in different size of follicular granulosa cells was higher different, and in the large follicular was significantly higher than that of middle follicle, expression quantity in the middle follicular was significantly higher than that in small follicular, it showed that Notch2 gene may be associated with granulosa cell proliferation; the expression quantity of Notch2 mRMA in different follicular granulosa cell was closely relative to the concentration of estrogen in follicular, suggested Notch2 may be involved in the synthesis of estrogen.Hesl mRNA expressed differential among small/middle follicular granulosa, and the trend was consistent with Notch2 mRNA expressed in the two kinds of cells, showed that during follicles from earlier stage to collect period, the Heslexpression may be regulated by Notch2, and it played an important role to follicular developmeng in this process.Expression of c-myc mRNA in theca cells and granulosa cells were significantly higher than that of small follicle and large follicle, and middle follicle in important turning point of follicle to atresia or develop to dominant follicle, indicated that c-myc gene could participate in regulating follicle development in this key stage. Expression of c-myc mRNA in theca cells and granulosa cells were significantly higher than that of small follicle, and the trend was consistent with Notch2 mRNA expression in the two kinds of cells, showed that Notch2 could regulated earlier stage develop to collect period through inducing c-myc expression.Immunohistochemical results showed that Notch2 protein was expressed in granulosa cells of the preantral follicles, granulosa cells and theca cells of the antral follicles. Besides, Expression of Notch2 proteion in granulosa cells of the preantral follicles was more than the preantral follicles. |
