Submitted to: Biology of Reproduction Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 9, 2010
Publication Date: November 1, 2010
Citation: Kim, J.G., Rohrer, G.A., Nonneman, D., Vallet, J.L. 2010. Molecular cloning of porcine chemokine CXC motif ligand 2 (CXCL2) and mapping to the SSC8 [abstract]. Biology of Reproduction. 83 (Special Issue):79 (Abstract # 351). Technical Abstract: Maternal recognition of pregnancy is accompanied by inflammatory responses with leukocytosis and increased levels of cytokines and chemokines. Human trophoblast cells secrete chemokine CXC motif ligand 1 (CXCL1)/Gro-a and other chemotactic proteins, while monocytes co-cultured with trophoblast cells secrete very high levels of chemokines including CXCL1. Seminal plasma elicits increased expression of pro-inflammatory cytokines and increased infiltration of inflammatory cells in pigs. CXCL1, CXCL2 and CXCL3 were originally cloned as growth-regulated genes. Due to their role in inflammatory response and growth regulation, these CXCLs may affect fetal survival and development during early pregnancy in pigs. Uterine capacity is a component trait contributing to litter size in pigs. Gene mapping analyses revealed a quantitative trait locus (QTL) for uterine capacity located on chromosome 8. Comparison to the human gene map suggests that the CXCL2/Gro-ß gene may be located near the region of the uterine capacity QTL. Its role in inflammatory response and growth modulating activity makes it a good candidate gene for the uterine capacity QTL. Complete coding sequence of porcine CXCL2 has not been reported previously. The objective of this study was to 1) clone CXCL2 cDNA, 2) map the gene and 3) obtain the gene structure. By RT-PCR using total RNA from the pig placenta, we obtained 948 bp of porcine CXCL2 cDNA. Then by iterative screening of a porcine reproductive tissue cDNA library, we obtained 1086 bp CXCL2 cDNA containing the start and stop codons, and poly A tail (GenBank acc. No. AY577905). The predicted 107 amino acid sequence of porcine CXCL2 is 74% identical to human CXCL2. Using two informative microsatellite markers, SB68 (GenBank accession No. AY577903) and SB69 (GenBank accession No. AY577904), developed from the RPCI-44 male porcine bacterial artificial chromosome (BAC) genomic library, CXCL2 gene was mapped to 65 cM on chromosome 8 within the same region as the previously identified uterine capacity QTL. The positive subclone containing the CXCL2 gene from the porcine BAC library was sequenced. The porcine CXCL2 gene (GenBank accession No. AY578786) is consisted of 4 exons and 3 introns. This is the first report of full coding region of porcine CXCL2 and the gene structure. The finding that CXCL2 mRNA is expressed in the placenta and the gene is mapped within the uterine capacity QTL suggests CXCL2 may play a role during early pregnancy in the pig.