Cloning of the rat IL-5R alpha gene: Analysis of 5 '-upstream region and expression by B cells

Although rats are widely used for the analysis of allergic reactions and pa rasitic infections where IL-5 is involved, nothing is currently known of th e expression of IL-5 receptor in this species. In this study, the cDNA sequ ence, genomic structure and the transcriptional regulation of the rat IL-5R alpha were analyzed. The rat IL-5R alpha gene, which we localized to chrom osome 4q34-q41, spans more than 25 kb and consists of 12 exons. Promoter ac tivity was seen in different cell lines and analysis by deletion experiment s allowed to identify two negative regulatory regions which did not differ when tested either with IL-5R alpha -negative or positive cells. Finally, t he investigation of the expression of IL-5R alpha showed that it is express ed in lung, spleen, liver, and purified rat B cells from normal rat. This c an provide an explanation for the role of rat IL-5 as B-cell growth factor and a relevant model in order to better understand the activity of IL-5 on human B Cells. (C) 2001 Academic Press.