Physiological effects of major genes affecting ovulation rate in sheep.
Genetic mutations with major effects on ovulation rate in sheep were recently identified in two genes of the transforming growth factor (TGFbeta) superfamily and a TGFbeta receptor, namely bone morphogenetic protein 15 (BMP15), otherwise known as the growth differentiation factor 9b (GDF9b), GDF9 and activin-like kinase 6 (ALK6) otherwise known as the BMP receptor type IB (BMPRIB). Animals homozygous for the BMP15 or GDF9 mutations are anovulatory whereas animals heterozygous for BMP15 or GDF9 or heterozygous or homozygous for ALK6 have higher than normal ovulation rates. Immunisation of ewes against BMP15 or GDF9 shows that both are essential for normal follicular development and control of ovulation rate. Common features of fertile animals with the BMP15, ALK6 (and possibly GDF9) mutations are changes in oocyte development during early preantral follicular growth, earlier maturation of granulosa cells and ovulation of mature follicles at smaller diameters. In summary, these findings have led to a new paradigm in reproductive biology, namely that the oocyte plays a key role in regulating the ovulation rate.
McNatty
Kenneth P
KP
AgResearch, Wallaceville Animal Research Centre, PO Box 40063, Upper Hutt, New Zealand. ken.mcnatty@agresearch.co.nz
Galloway
Susan M
SM
Wilson
Theresa
T
Smith
Peter
P
Hudson
Norma L
NL
O'Connell
Anne
A
Bibby
Adrian H
AH
Heath
Derek A
DA
Davis
George H
GH
Hanrahan
James P
JP
Juengel
Jenny L
JL
D028341:Activins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D005260:Female; D005786:Gene Expression Regulation; D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009865:Oocytes / Q000502:physiology; D006080:Ovarian Follicle / Q000254:growth & development; D010060:Ovulation / Q000235:genetics* / Q000502:physiology*; D012756:Sheep / Q000235:genetics* / Q000502:physiology*
D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins; D028341:Activins