HpaII PCR-RFLP within a Bov-A2 element in the promoter of the bovine CYP21 (steroid 21-hydroxylase) gene

Identification of a DNA methylation point in the promoter region of the bovine CYP21 gene

The CYP21 (steroid 21-hydroxylase) gene is involved in the synthesis of steroid hormones. Bov-A2 is a retroposon that is common in ruminant genomes. The promoter region of bovine CYP21 contains a short interspersed nucleotide element of Bov-A2, which overlaps a putative Sp1 binding site. We looked for RFLP/HpaII polymorphism in the Bov-A2 element in bovine Zebu breeds by PCR-RFLP, and examined whether polymorphism in this element is associated with methylation. Among DNA samples from 135 Brazilian Zebu breed cattle, we identified an RFLP/HpaII polymorphism (T/C), which, based on a restriction methylation-sensitive assay employing HpaII and isoschizomer MspI enzymes (methylation-sensitive and -non-sensitive enzymes, respectively), appears to be a DNA methylation point. This is the first report of this polymorphism and on DNA methylation in the bovine CYP21 promoter region in Brazilian Zebu cattle.

An analysis of CYP19, CYP21 and ER genotypes in Polish Holstein-Friesian cows with regard to the selected reproductive traits

The aim of this study was to relate polymorphic variants of CYP19, CYP21 and ER1 genes to reproductive traits in 472 Polish Holstein-Friesian cows. High frequencies of one of the homozygous genotypes were found. The ER1/SnaBIAA homozygotes were not identified. In the first and third lactation, an average calving-to-conception interval (CLVC) in cows of ER1/SnaBIGG genotype was significantly shorter (P ≤ 0.05) than in heterozygous cows. In the cows of ER1/BglIGG genotype, significantly shorter CLVC (P ≤ 0.05) was observed compared to heterozygotes in the first lactation, whereas in the third lactation, CLVC in homozygous cows was significantly longer (P ≤ 0.05) than in heterozygous ones. It was also found that homozygous cows were characterized by significantly longer calving interval (CLVI; P ≤ 0.05) compared to heterozygotes in the third lactation. Longer CLVCs in CYP19AA cows were found, compared to heterozygotes, and this difference was significant in the first and third lactation (P ≤ 0.05). Similarly, the average CLVIs were longer in CYP19AA homozygotes than in heterozygous cows; however, significance was proven only in the third lactation (P ≤ 0.05). Description of the molecular mechanisms regulating reproduction, and thus identification of the individuals of genotypes with optimal potential may facilitate the employment of selected reproductive model by a breeder.

Single nucleotide polymorphisms (SNPs) within Bov-A2 SINE in the second intron of bovine and buffalo k-casein (CSN3) gene

The genetic polymorphism of an entire Bov-A2 element located in the second intron of the buffalo and bovine k-casein (CSN3) gene was investigated by amplification and sequencing of PCR products. Single nucleotide polymorphisms were detected. A PCR-RFLP method was developed to detect an A or G mutation at position 605 of bovine Bov-A2 element which creates a BfaI polymorphic site. The frequencies of the B allele, with the BfaI site, were for 0.275, 0.775, 0.750, 0.975, respectively, for Italian Holstein Friesian, Grey Alpine, Friuli Red Pied and Reggio bovine breeds. The mutation rate (substitutions and deletions/insertions per nucleotide site per year) was 2.5 x 10(-9) for Bov-A2 sequences in the second intron of CSN3. The comparison with other Bov-A2 elements suggests that this retroelement might be an important source of single nucleotide polymorphism for analysis of Bovidae genomes.