Identification and genetic mapping of bovine chemokine genes expressed in epithelial cells

RNA fingerprinting by arbitrarily primed (RAP)-PCR was used to identify two bovine genes that were differentially expressed in epithelial cells during an inflammatory response. RNA fingerprints revealed two differentially amp lified transcripts when monolayers of Madin-Darby bovine kidney (MDBK) cell s were stimulated with Escherichia coli O157:H7 lipopolysaccharide (LPS) in combination with cycloheximide (CX). Sequence analysis showed that both tr anscripts encoded members of the alpha C-X-C chemokine family; one was inte rleukin 8 (IL-8), and the other was a protein closely related to bovine gro wth-regulated protein (GRO)-gamma (89% identical). The latter putative epit helial cell inflammatory protein was designated ECIP-1. IL-8 and ECIP-I gen es were placed on the cattle genetic map with single-nucleotide polymorphis m (SNP) markers amplified from genomic DNA. Multi-point linkage analysis in dicated that the gene locations were indistinguishable from those of serum albumin (ALB) and vitamin D-binding protein (GC) on bovine Chromosome (BTA) 6. In humans, ALE and GC are located near IL-8, GRO-gamma, and seven other alpha chemokines on Chr 4 (HSA 4q 11-4q13), suggesting that this gene clus ter has been conserved on BTA6. These results provide a starting point for characterizing allelic variation in chemokine genes and their role in the p athogenesis of bacterial infections in cattle.