The Relationship Between CRP Gene Polymorphism and the Serum Concentrations of C-Reactive Protein, Total Cholesterol and HDL Cholesterol in Suckling Piglets / Związek polimorfizmu genu CRP z koncentracją kodowanego białka C-reaktywnego, cholesterolu całkowitego i HDL-ch w surowicy krwi ssących prosiąt

Mutations on a conserved distal enhancer in the porcine C-reactive protein gene impair its expression in liver

C-reactive protein (CRP) is an evolutionary highly conserved protein. Like humans, CRP acts as a major acute phase protein in pigs. While CRP regulatory mechanisms have been extensively studied in humans, little is known about the molecular mechanisms that control pig CRP gene expression. The main goal of the present work was to study the regulatory mechanisms and identify functional genetic variants regulating CRP gene expression and CRP blood levels in pigs. The characterization of the porcine CRP proximal promoter region revealed a high level of conservation with both cow and human promoters, sharing binding sites for transcription factors required for CRP expression. Through genome-wide association studies and fine mapping, the most associated variants with both mRNA and protein CRP levels were localized in a genomic region 39.3 kb upstream of CRP. Further study of the region revealed a highly conserved putative enhancer that contains binding sites for several transcriptional regulators such as STAT3, NF-kB or C/EBP-β. Luciferase reporter assays showed the necessity of this enhancer-promoter interaction for the acute phase induction of CRP expression in liver, where differences in the enhancer sequences significantly modified CRP activity. The associated polymorphisms disrupted the putative binding sites for HNF4α and FOXA2 transcription factors. The high correlation between HNF4α and CRP expression levels suggest the participation of HNF4α in the regulatory mechanism of porcine CRP expression through the modification of its binding site in liver. Our findings determine, for the first time, the relevance of a distal regulatory element essential for the acute phase induction of porcine CRP in liver and identify functional polymorphisms that can be included in pig breeding programs to improve immunocompetence.

Association analysis of GH1 and CRP loci polymorphisms with reproductive traits in native Pulawska gilts and sows

The objective of the study was to analyse the association of growth hormone (GH1) and C-reactive protein (CRP) loci polymorphisms with reproductive traits in native Pulawska gilts and sows. In the GH1 locus, two mutations were identified: one in the second intron [single-nucleotide polymorphism (SNP) = rs340429823 in.742C>T, MspI], and one in the second exon (SNP = rs340087546 c.566G>A, HaeII). In the CRP locus, two mutations were found in exon 2 (SNP = rs340175625, NM_213844.2: c.1271A>G, BstNI; and SNP = rs80928546, NM_213844.2: c.788C>T, HinfI). Analysis of sexual activity showed that intensity of external estrus signs differed significantly (P ≤ 0.05) and was the most manifested in gilts with the CT (GH1_MspI) genotype during the second estrus. In case of the CRP gene, statistically significant differences (P ≤ 0.05) were found in terms of the duration of farrowing. The longest farrowings were reported for the GG (CRP_HinfI) and the TT (CRP_BstNI) genotypes and the shortest for the AA (CRP_HinfI) and CC (CRP_BstNI). The most numerous first litters were produced by sows with the AA genotype (CRP_HinfI), with significant differences (P ≤ 0.05) between the AA and GG genotypes. In turn, the CC homozygotes (CRP_BstNI) differed significantly (P ≤ 0.05) in terms of the number of piglets born and reared to day 21 in the second litters compared to the other genotype groups.