Search

Fresh semen from fifty bulls was evaluated for ejaculate volume, individual motility, concentration, lives sperm and abnormalities as well as acrosome integrity. Bulls were classified according to semen motility into two groups; good and poor. DNA was extracted from semen of both groups, then the PCR followed by single-strand conformation polymorphism (SSCP) techniques were performed for mutation detection in gonadotropin releasing hormone receptor (GnRHR) gene through multiple sequence alignment. The results showed that the percentages of sperm motility, sperm concentration and live sperm, were significantly higher in good than poor semen quality bulls. However, semen volume, percentage of acrosome integrity and abnormalities did not differ between good and poor. The PCR amplification of 240-bp fragment and the results of SSCP appeared a genetic polymorphism with two patterns. Pattern I was seen in all good bulls, with incidence of 100%. Pattern II appeared only in poor semen quality bulls with a frequency of 31.25%. The sequence analysis of the PCR product for the two patterns showed two single nucleotide polymorphisms (SNPs) as a transversion base substitution mutation at positions 20 (T/A) and 193 (A/T). The GnRHR gene could be used as a genetic marker related to semen quality in buffalo due to the good semen bulls had a unique pattern.

The hypothalamic gonadotropin-releasing hormone receptor (GnRHR) plays an essential physiological role in reproductive function. In this investigation, we studied genetic variation in the entire coding region of GnRHR gene using PCR-SSCP technique in 250 Bos taurus (Holstein Friesian, Jersey) and Bos indicus (Malnad Gidda, Deoni) bulls. The genetic variants in GnRHR gene were determined by PCR-SSCP technique by using 5 sets of primers. SSCP analysis of fragment 1, comprising exon 1, and fragment 3, comprising exon 2, revealed 2 SSCP patterns in all breeds under study, while fragment 2 of exon 1 and fragment 4, comprising exon 3, revealed 3 patterns in Malnad Gidda; Holstein Friesian and Deoni breeds showed 2 SSCP patterns. In Jersey bulls, fragment 4 showed 3 patterns. The fragment 5 comprising exon 3 was monomorphic in all 4 breeds under study. SNPs were confirmed by direct sequencing. The sequence analysis revealed 7 transitions (T940C, T1021C, T1090C, T1174C, T13940C, T18023C, and G17887A), 3 transversions (G13817C, G17926C, and G17926C), 2 deletions (854DA and 17684DT), and 2 insertions (1009IA and 180100IC) in GnRHR gene. The study revealed high genetic variation in GnRHR gene in cattle.

We report a novel GNRHR mutation in a male with normosmic isolated hypogonadotropic hypogonadism (nIHH). The coding region of the GNRHR gene was amplified and sequenced. Three variants p.[Asn10Lys;Gln11Lys]; [Tyr283His] were identified in the GNRHR coding region in a male with sporadic complete nIHH. The three variants were absent in the controls (130 normal adults). Familial segregation showed that the previously described p.Asn10Lys and p.Gln11Lys are in the same allele, in compound heterozygozity with the novel variant p.Tyr283His. The p.[Asn10Lys;Gln11Lys] are known inactivating mutations. The p.Tyr283His affects a well-conserved residue, and in silico analysis suggested it is a deleterious variant. We describe a novel GNRHR mutation in a male with nIHH. Absence of the mutation in the control group, conservation among species, in silico analysis, and familial segregation suggest that p.Tyr283His, which was identified in compound heterozygozity with the p.[Asn10Lys;Gln11Lys] variants, is an inactivating mutation. Arq Bras Endocrinol Metab. 2012;56(8):540-4 Relatamos uma nova mutação no gene GNRHR em um homem com hipogonadismo hipogonadotrófico isolado normósmico (HHIn). A região codificadora do gene GNRHR foi amplificada e sequenciada. Três variantes p.[Asn10Lys;Gln11Lys]; [Tyr283His] foram identificadas no GNRHR em um homem com HHIn esporádico. As três variantes estavam ausentes no grupo controle (130 adultos normais). A segregação familiar mostrou que as variantes previamente descritas p.[Asn10Lys;Gln11Lys] se localizavam no mesmo alelo, em heterozigose composta com a nova variante p.Tyr283His. As mutações p.[Asn10Lys;Gln11Lys] são sabidamente inativadoras. A variante p.Tyr283His afeta um resíduo bem conservado, e a análise in silico sugeriu que essa é uma mutação deletéria. Descrevemos uma mutação inédita no gene GNRHR em um paciente com HHIn nIHH. A ausência da variante no grupo controle, a conservação entre as espécies, a análise in silico e a segregação familiar sugerem que a p.Tyr283His é uma mutação inativadora, identificada em heterozigose composta com as mutações p.[Asn10Lys;Gln11Lys]. Arq Bras Endocrinol Metab. 2012;56(8):540-4