Clock genes, such as cryptochrome 1 (CRY1), exhibit rhythmic expression in the reproductive organs. This gene is a key component of the circadian clock and is involved in various physiological processes, including reproduction, suggesting that it may be linked to ovarian activity via neuroendocrine pathways. However, the association between CRY1 variants and ovarian traits in dairy cows is unclear. In this study we used qRT-PCR to assay the mRNA expression of this gene, and found that CRY1 expression was highest in oocytes in several tissues; subsequently, we found that CRY1 expression was highest in the ovary in Chinese Holstein dairy cattle, followed by muscle and spleen tissues (p < 0.01). Next, we identified a six bp insertion/deletion (indel) locus within the CRY1 gene in Chinese Holstein dairy cattle. Only two genotypes were detected: II (n = 854, 83.7%) and ID (n = 166, 16.3%). Association analysis revealed that the identified indel was significantly associated with dominant follicle and corpus albicans diameters (p < 0.05) during metestrus. Specifically, individuals with the ID genotype exhibited smaller dominant follicles and corpus albicans than those with the II genotype. Our preliminary findings suggest that CRY1 is associated with specific ovarian morphological traits and may serve as a basis for further investigation of its potential role in bovine reproductive function.
Xuanbo Chen, Enhui Jiang, Yuta Yang et al.· Biomolecules· 0 citations
The genetic and physiological variations among individuals of Holstein dairy cattle contribute to variations in milk yield. Selecting high-yield cows is critical for improving lactation performance. The present study aimed to identify functional genetic variants of the 3′ untranslated region (3′ UTR) in the ELF5 gene associated with milk production traits and to elucidate their underlying molecular mechanisms. A total of 1314 Chinese Holstein cows were genotyped, and a novel single nucleotide polymorphism (SNP), ELF5 g.32793 G>T, was identified in the 3′ UTR of ELF5. This SNP was significantly associated with milk production, such as milk yield, milk fat percentage, milk protein percentage, and somatic cell score. Bioinformatic prediction and dual-luciferase reporter assays demonstrated that the ELF5 g.32793 G>T affects the interaction between bta-miR-487a and the ELF5 3′ UTR. Functional analyses in bovine mammary epithelial (MAC-T) cells showed that bta-miR-487a suppressed cell proliferation by inducing G0/G1 phase arrest and reduced the expression of proliferation-related proteins. Collectively, these findings suggested that bta-miR-487a participates in the regulation of MAC-T cell growth and that the ELF5 g.32793 G>T polymorphism may influence lactation performance through an miRNA-associated mechanism. Therefore, the variant can be used as a functional marker for marker-assisted selection in dairy cattle breeding.
Lin Ma, Li Sun, Haotian Zhang et al.· Biomolecules· 0 citations