Expression data from mouse model of Ecoli mastitis

We performed a genome-wide transcriptional analysis in the mammary gland in a mouse model of E. coli mastitis using high-density mouse oligonucleotide microarrays. This global transcription analysis revealed that about 7% of tested genes are mobilized in the mouse mammary gland to E. coli endotoxin. We identified 1402 differentially expressed genes that were associated with physiological system development/function and molecular/cellular functions and metabolic/signalling pathways that are highly relevant to host immune-inflammatory defense response against E. coli infection. The mouse differentially expressed genes through the use of comparative mapping/genomics and positional information on reported QTL for bovine mastitis allowed identifying 293 potential candidate genes for bovine mastitis. This study will enable other researchers to combine our mRNA expression data with genetic association studies to discover genomic variation underlying variation of susceptibility to mastitis in dairy cows. Keywords: time course, disease state analysis This study was conducted using a split-plot design. We measured levels of gene expression in healthy (saline injected) and diseased (E. coli injected) mammary gland tissue (treatment = 2, in sub-plots). The mammary tissue samples were collected at two-time points: 24 hr and 48 hr post-injection (time = 2, in main-plots). Each inbred mouse was injected with both treatments: the 4th left mammary gland was injected with saline solution and the 4th right mammary gland was injected with E. coli solution (mice = 4). The expression profiling was carried out using two biological replications (replication = 2) at each time point.