THE BOVINE INTERLEUKIN-4 GENE - GENOMIC ORGANIZATION, LOCALIZATION, AND EVOLUTION

Interleukin-4(IL4) is involved in the immune response to certain paras ites and possibly in the development of some atopic diseases since it triggers the T helper 2 lymphocyte response. Therefore, IL4 is a candi date gene, for example, for disease association studies and gene mappi ng. We isolated bovine IL4 cosmids and determined the genomic organiza tion. Fragments carrying the exons as well as 725 base pairs (bp) from the 5' flanking and 190 bp from the 3' flanking region were cloned an d sequenced. The first 481 base pairs of the 5' flanking region, inclu ding the putative promoter sequences, are surprisingly similar (92%) b etween cattle and human. Ln addition, we cloned and sequenced a mixed [(t/g)a](m)(ca)(n) repeat located approximately 35 kilobases upstream from the IL4 gene. It showed seven repeat length alleles in a limited number of animals. The IL4 gene has been assigned to 7q15-q21 by fluor escence in situ hybridization in cattle. Evolutionary aspects are disc ussed on the basis of sequence data as well as interspecies chromosoma l homologies.