DLG1 - CHROMOSOME LOCATION OF THE CLOSEST HUMAN HOMOLOG OF THE DROSOPHILA DISCS LARGE TUMOR-SUPPRESSOR GENE

The Drosophila discs large tumor suppressor protein, Dig, is the proto type of a newly discovered family of proteins termed MAGUKs (membrane- associated guanylate kinase homologues), MAGUKs are localized at the m embrane-cytoskeleton interface, usually at cell-cell junctions, where they appear to have both structural and signaling roles, They contain several distinct domains, including a modified guanylate kinase domain , an SH3 motif, and one or three copies of the DHR (GLGF/PDZ) domain. Recessive lethal mutations in the discs large tumor suppressor gene in terfere with the formation of septate junctions (thought to be the art hropod equivalent of tight junctions) between epithelial cells, and th ey cause neoplastic overgrowth of imaginal discs, suggesting a role fo r cell junctions in proliferation control. A homologue of the Dig prot ein, named Hdlg, has been isolated from human B lymphocytes, It shows 65-79% identity to Dig in the different domains, and it binds to the c ytoskeletal protein 4.1. Here, we report that the gene for lymphocyte Hdlg, named DLG1, is located at chromosome band 3q29. This finding ide ntifies a novel site for a candidate tumor suppressor on chromosome 3. (C) 1995 Academic Press, Inc.