GENOMIC SEQUENCE, ORGANIZATION, AND CHROMOSOMAL LOCALIZATION OF HUMANJAK3

Members of the Janus (JAK) protein tyrosine kinase family including JA K3 have recently emerged as important components in cytokine signal tr ansduction. Mutations of JAK3 have been found in a number of patients who present with severe combined immunodeficiency. To facilitate the f urther identification of JAK3-SCID patients and to understand the stru cture of JAK3 better, we undertook the determination of the genomic se quence, organization, and chromosomal localization of the JAK3 gene, T he JAK3 gene was found to consist of 19 exons and 18 introns. Interest ingly, the organization of the kinase-(JH1) and pseudokinase-(JH2) dom ains were found to be dissimilar. In addition, the JAK3 gene was local ized to human chromosome 19p13.1. These data should facilitate the ide ntification of patients with this new form of immunodeficiency and wil l provide insight into the structure of this kinase. (C) 1996 Academic Press, Inc.