Cloning of the Gene for Bovine Monocyte Chemoattractant Protein-2

Abstract

Bovine monocyte chemoattractant protein-1 (bovine MCP-1) cDNA has recently been characterized and shown to be highly expressed in bovine seminal vesicles secretory epithelium as well as in phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear leukocytes (PMNLs). In an attempt to isolate the MCP-1 gene, we screened a bovine genomic cosmid library with a MCP-1-specific probe pH42. A positive clone, c11/1, was subjected to restriction analysis and fragments probed with pH42 by southern blotting. pH42-positive fragments were subcloned and sequenced. The sequence revealed three exon-like regions that coded for a protein displaying an identity of 51% with bovine MCP-1. Employing this sequence information from c11/1, the c11/1-specific cDNA was generated from poly(A)+RNA of bovine PMNLs by reverse transcription and a combination of polymerase chain reaction (PCR) methods. The assembled c11/1 cDNA comprised a 5' UTR coding region as well as 3' UTR for the gene product c11/1. Amino acid sequence comparison of the bovine c11/1 gene product with human monocyte chemotactic proteins yielded the highest sequence identity with human MCP-2, and it is assumed that the c11/1 gene product represents the bovine MCP-2. The exon/intron structure of the bovine MCP-2 gene was found to be similar to the human MCP-1 gene. The bovine MCP-2 gene consists of three exons separated by two introns. In the 5'-flanking region of the 3.3-kb gene, a TATA box as well as an AP-1 sequence motif were identified. The bovine MCP-2 is specified by a single-copy gene.(ABSTRACT TRUNCATED AT 250 WORDS)