Role of the SHP-1 tyrosine phosphatase in the regulation of oocyte growth and follicle development.

Abstract

The tyrosine kinase Kit is expressed in oocytes and is involved in primordial germ cell (PGC) proliferation and oocyte growth. Our goal was to determine the involvement of the SHP-1 phosphatase in regulating PGC proliferation and oocyte growth by examining SHP-1 deficient motheaten mice. Ovaries from wild-type and motheaten mice were observed at 10--13 days of age and after transplantation under the kidney capsule of SCID mice. Ovaries were analyzed by histological and western analyses. SHP-1 was expressed in all ovarian cell types throughout follicle development. At 10--13 days, motheaten animals had smaller ovaries, increased numbers of PGCs and decreased granulosa cell proliferation compared to controls. After transplantation, both groups had formed large antral follicles in similar proportions. Interestingly, motheaten oocytes achieved larger sizes than controls. These results suggest that SHP-1 may interact with Kit to regulate PGC proliferation and oocyte growth, however, the loss of SHP-1 does not impair granulosa cell proliferation and follicle development.