RESUMO
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.
Assuntos
Antígenos CD4/genética , Marcadores Genéticos , Mastite Bovina/genética , Animais , Antígenos CD4/imunologia , Bovinos , Feminino , Genótipo , Haplótipos , Desequilíbrio de Ligação/genética , Mastite Bovina/patologia , Leite/metabolismo , Fenótipo , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNARESUMO
The effects of virus-like double-stranded RNA (dsRNA, PolyI:C) and DNA methyltransferase inhibitor (Aza-CdR) on CD4 gene expression were investigated in a porcine kidney cell line (PK15). We found that expression levels of TLR3 and IFNαwere significantly upregulated by PolyI:C, compared to the untreated PK15 cells, which shows that PolyI:C successfully mimics viral infection in PK15 cells. We also found that PolyI:C (10 µg/ml) and/or Aza-CdR (5 µM) significantly induces DNA demethylation of porcine CD4, promoting the binding of NF-κB to the CpG site on the CD4 promoter and activating expression of CD4. These data help clarify the regulatory mechanism of DNA methylation of the CD4 gene in non-immune cell response to virus replication. Further study is warranted to identify CD4 gene expression regulated by DNA methylation and live virus infection.
Assuntos
Antígenos CD4/biossíntese , Metilação de DNA/efeitos dos fármacos , Metiltransferases/genética , RNA de Cadeia Dupla/genética , Animais , Inibidores Enzimáticos/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/enzimologia , Regulação da Expressão Gênica , Rim/citologia , Rim/efeitos dos fármacos , Metiltransferases/antagonistas & inibidores , Regiões Promotoras Genéticas , Suínos , Replicação Viral/genéticaRESUMO
Vascular endothelial growth factor (VEGF) has been found responsible for the induction of proliferation and differentiation in granulosa cells. We constructed four short hairpin RNA (shRNA) expression plasmids targeting the mouse VEGFA gene, and examined their effect on VEGF expression in mouse granulosa cells (MGC) in vitro. Four different shRNA oligonucleotides targeting the coding sequence of mouse VEGFA mRNA and one negative control (shNC) were designed and cloned into a pGPU6/GFP/Neo siRNA expression vector, and transiently transfected into MGC. At 48 h post-transfection, total RNA was extracted from the cells and subjected to qRT-PCR analysis. The most effective interference vector, shVEGF1487 was chosen for lentiviral construction. The recombinant plasmid was then transfected into 293FT cells via Lipofectamine(TM) 2000-mediated gene transfer, for the production of lentivirus, and then concentrated via ultracentrifugation. This lentiviral vector was then used for the transduction of MGC. VEGFA gene expression, apoptosis genes and VEGFA receptor genes were detected by qRT-PCR, the VEGFA protein level in culture media by ELISA assay and protein levels in MGC by Western blot analysis. The four VEGFA expression plasmids were successfully constructed and the most effective interference vector, shVEGF1487, was chosen for lentiviral production and MGC transduction. There was significant knockdown of the VEGFA gene, receptor genes and apoptosis genes for all the shVEGF constructs, compared with the shNC and Mock controls. The lentiviral vector also gave significant knockdown of the VEGFA gene. Protein levels were lower for most of the shVEGFs based on Western blot analysis with exception of VEGF1359; in this case, it was higher than shNC but lower than for the Mock group. Lentivector-transduced MGC also gave lower levels of protein. We conclude that shVEGF expression plasmids and lentivector carrying RNAi are promising tools for the inhibition of VEGF, the corresponding receptor genes, and apoptosis gene expression in MGC.