Mutation in the protease cleavage site of GDF9 increases ovulation rate and litter size in heterozygous ewes and causes infertility in homozygous ewes

Abstract

Litter size (LS) in sheep is determined mainly by ovulation rate (OR). Several polymorphisms have been identified in the growth differentiation factor 9 (GDF9) gene that result in an increase in OR and prolificacy of sheep. Screening the databank of the Brazilian Sheep Breeders Association for triplet delivery, we identified flocks of prolific Ile de France ewes. After resequencing of GDF9, a point mutation (c.943C>T) was identified, resulting in a non-conservative amino acid change (p.Arg315Cys) in the cleavage site of the propeptide. This new allele was called Vacaria (FecG(v) ). A flock of half-sib ewes was evaluated for OR in the first three breeding seasons, and Vacaria heterozygotes had higher OR (P < 0.001), averaging 2.1 ± 0.1 when compared to 1.2 ± 0.1 in wild-type ewes. The OR was also influenced by age, increasing in the second and third breeding seasons (P < 0.001). In flocks segregating this allele, the LS was higher in mutant sheep (P < 0.001), averaging 1.61 ± 0.07 in heterozygotes and 1.29 ± 0.03 in wild-type ewes. Analysis of homozygote reproductive tract morphology revealed uterine and ovarian hypoplasia. Ovarian follicles continue to develop up to small antral stages, although with abnormal oocyte morphology and altered arrangement of granulosa cells. After the collapse of the oocyte in most follicles, the remaining cells formed clusters that persisted in the ovary. This SNP is useful to improve selection for dam prolificacy and also as a model to investigate GDF9 post-translation processing and the fate of the follicular cells that remain after the oocyte demise.

Novel Variants in GDF9 Gene Affect Promoter Activity and Litter Size in Mongolia Sheep

“…Mutations in BMP15 were detected in Romney and Inverdale (FecX H and FecX I ) [4], Cambridge and Belclare (FecX B and FecX G ) [5], Lacaune (FecX L ) [14], Rasa Aragonesa (FecX R ) [15], Olkuska (FecX O ) and Givette (FecX Gr ) [16], and Barbarine sheep (FecX Bar ) [17]. The GDF9 mutations were observed in Cambridge and Cambridge (FecG H ) [5], Thoka (FecG T ) [18], Santa Ines (FecG E ) [19], Baluchi (FecG 1 ) [20], Norwegian White Sheep, Finn Ile de France sheep and Belclare (FecG F ) [21,22], Ile de France (FecG V ) [23], and Araucana creole sheep (FecG A ) [24]. The FecL L and FecD D mutations were seen in Lacaune [6] and Davisdale [7] sheep, respectively (Table 1).…”

Tissue-specific mRNA expression profiles of GDF9, BMP15, and BMPR1B genes in prolific and non-prolific goat breeds

“…Bone morphogenetic protein 15 (BMP15), growth differentiation factor 9 (GDF9), and bone morphogenetic protein receptor, type IB (BMPR1B), known as prolificacy candidate genes, play key roles in regulating ovarian functions in animals (Juengel et al 2002;Knight and Glister 2003 showed that ovulation rate in the heterozygotes was increased, but homozygous mutants were completely sterile (Galloway et al 2000;Hanrahan et al 2004;Bodin et al 2007;Martinez-Royo et al 2008;Monteagudo et al 2009). The mutations of GDF9 (FecG H , FecG T , FecG E , FecG F , and FecG V ) had introduced nonconservative amino acid changes reported to be associated with the litter size of sheep (Melo et al 2008;Nicol et al 2009;Silva et al 2011;Vage et al 2013;Souza et al 2014). A variation (FecB) in BMPR1B caused substitution of one amino acid (arginine to glutamine) and increased the ovulation rate of ewes (Mulsant et al 2001;Souza et al 2001;Fabre et al 2003).…”

Growth and differentiation factor 9 promotes oocyte growth at the primary but not the early secondary stage in three-dimensional follicle culture

“…GDF9 is expressed by growing oocytes beginning at the primary stage across a range of species, from rodents [12][13][14][15] to humans [16], and is required for growth of the primary follicle as knocking GDF9 out in mice results in arrest of folliculogenesis at the primary stage [17]. A similar phenotype was also observed in sheep with homozygous mutations in GDF9 [18][19][20]. GDF9 might also play a role at the primary stage in human folliculogenesis, as follicles of women with PCOS have decreased GDF9 expression and demonstrate a slowing of the primary to secondary follicle transition [21][22][23].…”

“…Sustained growth of early follicles-specifically, late primary and early secondary follicles-to the antral stage has been achieved in vitro with organ culture [24,[43][44][45] or coculture of isolated follicles with ovarian stromal cells [46][47][48][49], mouse embryonic fibroblasts [50], multiple other follicles [25], or supplemented media [51]. Together, these findings suggest that follicle growth at the primary and early secondary stages is enhanced by, and perhaps dependent upon, factors from the surrounding ovarian environment in addition to the critical role played by the oocyte-derived factor GDF9 [6,7,[17][18][19][20][21][22][23].…”