Using the knockout mouse model, it has been proven that NOBOX regulates different gene expressions specific for the oocyte, including BMP-15 and GDF-9(31).
They are responsible for the follicle early growth and differentiation by control of a number of genes including NOBOX, FIGLA, BMP-15 and GDF-9(12).
It was shown that supplementation of culture media with BMP-15 maintained the ultrastructural integrity of isolated caprine pre-antral follicles and promoted the growth of pre-antral follicles cultured for seven and 18 days (13, 20, 21).
Integral role of GDF-9 and BMP-15 in ovarian function.
GCNF-dependent repression of BMP-15
and GDF-9 mediates gamete regulation of female fertility.
Expression of bone morphogenetic protein 15 (BMP-15
) during In vitro maturation in canine oocytes.
These results showed that BMP-15
gene is a genetic marker and closely linkage to the litter size trait and consequently can be used as a marker-assisted selection (MAS) for high litter size productivity in sheep.
The two genes GDF-9 and BMP-15
have made their sources in oocytes (Juengel et al., 2002).
In mammals BMP-15
is the product of an X-linked gene expressed in oocytes (Dube et al., 1998; Laitinen et al., 1998; Grapes and Rothschild, 2002; Silva et al., 2005).
Study of BMP-15
gene polymorphism in Iranian goats, African J.
In addition, GDF-9, as well as bone morphorgenic protein-15 (BMP-15
) from oocytes, mediates other regulatory effects of the oocyte on cumulus cells (Bodin et al., 2007).
Members of each subgroup (BMP-2, BMP-4, BMP-6, BMP-7, BMP-15
, and growth differentiation factor-9(GDF-9)) have been shown to affect ovarian folliculogenesis, follicular growth and differentiation, cumulus expansion, ovulation and luteinization (Knight and Glister, 2006).