Species: ovine
Mutation name: None
type: naturally occurring
fertility: fertile
Comment: The Highly Prolific Phenotype of Lacaune Sheep Is Associated with an Ectopic Expression of the B4GALNT2 Gene within the Ovary. Drouilhet L 2013 et al. Prolific sheep have proven to be a valuable model to identify genes and mutations implicated in female fertility. In the Lacaune sheep breed, large variation in litter size is genetically determined by the segregation of a fecundity major gene influencing ovulation rate, named FecL and its prolific allele FecL(L) . Our previous work localized FecL on sheep chromosome 11 within a locus of 1.1 Mb encompassing 20 genes. With the aim to identify the FecL gene, we developed a high throughput sequencing strategy of long-range PCR fragments spanning the locus of FecL(L) carrier and non-carrier ewes. Resulting informative markers defined a new 194.6 kb minimal interval. The reduced FecL locus contained only two genes, insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) and beta-1,4-N-acetyl-galactosaminyl transferase 2 (B4GALNT2), and we identified two SNP in complete linkage disequilibrium with FecL(L) . B4GALNT2 appeared as the best positional and expressional candidate for FecL, since it showed an ectopic expression in the ovarian follicles of FecL(L) /FecL(L) ewes at mRNA and protein levels. In FecL(L) carrier ewes only, B4GALNT2 transferase activity was localized in granulosa cells and specifically glycosylated proteins were detected in granulosa cell extracts and follicular fluids. The identification of these glycoproteins by mass spectrometry revealed at least 10 proteins, including inhibin alpha and betaA subunits, as potential targets of B4GALNT2 activity. Specific ovarian protein glycosylation by B4GALNT2 is proposed as a new mechanism of ovulation rate regulation in sheep, and could contribute to open new fields of investigation to understand female infertility pathogenesis. /////////////////////////

Species: ovine
Mutation name:
type: naturally occurring
fertility: fertile
Comment: Molecular Cloning of the B4GALNT2 Gene and Its Single Nucleotide Polymorphisms Association with Litter Size in Small Tail Han Sheep. Guo X et al. (2018) A new fecundity gene named the FecL (mutation), which regulates the ovulation rate, was discovered in French Lacaune sheep. The B4GALNT2 (beta-1, 4-N-acetyl-galactosaminyl transferase 2) gene was considered as the potential FecL mutation gene. This study explores whether the effect of the FecL mutation exists in other sheep breeds, and the features of the B4GALNT2 gene in terms of the molecular structure and its expression profile. Using Sanger sequencing, we found that high and low fecundity breeds from among 11 measured sheep breeds all had no variation in the three specific mutation sites, which were linked with the FecL mutation. However, two mutations of g.36946470C > T and g.36933082C > T in the exon of B4GALNT2 had a significant effect on litter size in the first parity for Small Tail Han (STH) Sheep (p < 0.05). Two transcription start sites (TSS) of B4GALNT2 in its 5'-flanking region were discovered in ovine granule cells in vitro, through the RACE (Rapid amplification of cDNA ends) method. Except for in the kidney and oviduct, no significant difference in expression levels had been found between STH sheep and Tan sheep breeds. The B4GALNT2 gene, as a candidate for FecL, may have a relationship with the differences in litter size in STH sheep. B4GALNT2 is mainly expressed in the ovine ovary, which also suggests that B4GALNT2 plays an important role in sheep reproduction.//////////////////