|Heaton, Michael - Mike|
|Bono, James - Jim|
Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/6/2003
Publication Date: 5/17/2004
Citation: CHITKO MCKOWN, C.G., FOX, J.M., MILLER, L.C., HEATON, M.P., BONO, J.L., KEEN, J.E., GROSSE, W.M., LAEGREID, W.W. GENE EXPRESSION PROFILING OF BOVINE MACROPHAGES IN RESPONSE TO ESCHERICHIA COLI O157:H7 LIPOPOLYSACCHARIDE. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY. 2004. V. 28. P. 635-645.
Interpretive Summary: Microarrays or "gene chips" can be manufactured containing the sequences of greater than 10,000 genes and are used to measure levels of gene expression. These arrays are commercially available for many species, however, cattle are not among them. We hypothesized that due to the high level of homology between the human and bovine genes, we could probe human microarrays with bovine gene expression probes. The experiments were performed using RNA harvested from bovine monocyte-derived macrophages that were either treated with lipopolysaccharide (LPS) from the food-borne pathogen E. coli O157:H7 or untreated. In our study, bovine cDNA probe solutions hybridized to approximately 80% of the non-control gene targets on a human microarray. Of these targets, 0.6% were differentially expressed upon exposure to LPS, including 18 genes not previously reported to exist in cattle. LPS-treated and control probe solutions consistently hybridized to targets constitutively expressed by macrophages, thereby, demonstrating the specificity of this system. This first report of bovine-human cross-species expression profiling by microarray hybridization demonstrates the utility of this technique in bovine gene expression and discovery.
Technical Abstract: The aim of this study was to identify changes in bovine macrophage gene expression in response to treatment with Escherichia coli 0157:H7 lipopolysaccharide (LPS), utilizing a human gene microarray. Bovine cDNA from control and LPS-treated primary macrophages hybridized to greater than 5,644 (79.8%) of the non-control gene targets on a commercially available microarray containing greater than 7,075 targets (Incyte Genomics, St. Louis, Mo.). Of these target sequences, 0.6% were differentially expressed upon exposure to LPS, including 18 genes not previously reported to exist in cattle. These included a pentaxin-related gene, CASP8, TNF-induced genes, interferon-induced genes, and inhibitors of apoptosis. Using the human microarray, cDNA from bovine LPS-treated and control macrophages consistently hybridized to targets known to be expressed constitutively by macrophages, demonstrating the specificity of this system. Specificity was further verified by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) using bovine-specific primers. This first report of bovine-human cross-species expression profiling by microarray hybridization demonstrates the utility of this technique in bovine gene expression and discovery.