No abstract

Perilipins have been reported to limit the interaction of lipases with neutral lipids within the droplets, thereby regulating neutral lipid accumulation and utilization. This study aimed to identify the location and expression of PLIN1 and PLIN2 in porcine oocytes during maturation. Quantitative real-time polymerase chain reaction (qRT-PCR), immunostaining and Western blot methods were used to characterize the expression and distribution patterns of PLIN1 and PLIN2 in porcine oocytes. The results showed that PLIN1 was not detectable in porcine oocytes. PLIN2 and BODIPY 493/503-detected neutral lipid droplets appeared identical distribution patterns and extensive colocalization in both GV and MII porcine oocytes. PLIN2 protein expression was higher in GV oocytes than that in MII oocytes (p < 0.05), although PLIN2 mRNA expression was similar in both groups. These findings suggested that PLIN2 was a major lipid droplet-associated protein in porcine oocytes.

It has been demonstrated that extracellular calcium is necessary in fertilisation and embryo development but the mechanism is still not well understood. The present study mainly focussed on the extracellular calcium effector called the calcium-sensing receptor (CASR) and examined its expression in porcine gametes and embryos and its function during fertilisation and early embryo development. By using reverse transcription polymerase chain reaction, CASR was found to be expressed in porcine oocytes, spermatozoa and embryos at different developmental stages. Functionally, medium supplementation with a CASR agonist or an antagonist during in vitro fertilisation (IVF) and in vitro culture (IVC) was tested. During fertilisation, the presence of a CASR agonist increased sperm penetration rate and decreased polyspermy rate leading to an increased normal fertilisation rate. During embryo development, for the IVF embryos, agonist treatment during IVC significantly increased cleavage rate and blastocyst formation rate compared with the control group. Furthermore, parthenogenetically activated embryos showed similar results with lower cleavage and blastocyst formation rates in the antagonist group than in the other groups. It was concluded that CASR, as the effector of extracellular calcium, modulates porcine fertilisation and early embryo development.

ABSTRACT. Cluster of differentiation 4 gene (CD4) is well known for its role in immunity, but its effects on production traits remain to be elucidated. The present study was designed to explore single nucleotide polymorphisms (SNPs) in the exons, flanking introns, and promoter of CD4, as well as to analyze their effects on milk production traits (percentage of protein, fat, and lactose; mastitis indicator traits somatic cell count; and somatic cell score). A total of 10 SNPs, including eight in the exon and two in the intron regions, were identified using pooled DNA sequencing. These SNPs were screened in a population of 258 Chinese Holstein using the SNaPshot technique. We analyzed the effects of SNPs, parity, herd, year, and season of calving on the production and mastitis indicator traits. Our analysis revealed two haplotypes and strong linkage disequilibrium (D' > 0.97) among all SNPs. All 10 SNPs were significantly associated with fat percentage (P < 0.01). Cows homozygous for the wild-type genotypes had higher fat percentages than those with the other genotypes. The dominant and additive effects were also significant for fat percentage (P < 0.05). These results suggest that CD4 plays a role in production traits as well as in immune function. The identified SNPs could be used as genetic markers for selection of dairy cows with improved fat percentage. We propose further studies of these SNPs in a larger population as well as further investigations of the function of this gene.