THE CD39-LIKE GENE FAMILY - IDENTIFICATION OF 3 NEW HUMAN MEMBERS (CD39L2, CD39L3, AND CD39L4), THEIR MURINE HOMOLOGS, AND A MEMBER OF THE GENE FAMILY FROM DROSOPHILA-MELANOGASTER

The human lymphoid cell activation antigen CD39 is a known E-type apyr ase that hydrolyzes extracellular ATP and ADP, a function important in homotypic adhesion, platelet aggregation, and removal by activated ly mphocytes of the lytic effect of ATP. The recently identified putative rat homologue of CD39L1 has been shown to have E-type ecto-ATPase act ivity, by hydrolyzing extracellular ATP. We have characterized three n ovel CD39-like transcripts, CD39L2, CD39L3, and CD39L4, which share ex tensive amino acid homology with other nucleotide triphosphatases in v ertebrates, invertebrates, and plants, suggesting that these genes als o encode proteins with ecto-nucleotidase activity. Isolation and seque ncing of full-length cDNA clones for each gene identified putative pro teins of 485, 529, and 429 amino acids. The expression pattern of all five human members of the gene family was analyzed. CD39L2, CD39L3, an d CD39L4 were mapped on the human genome, and the murine homologues id entified with the putative map locations were assigned on the basis of regions of conserved gene order between human and mouse chromosomes. The map location of mcd3914 places the gene within a region associated with audiogenic seizure susceptibility in mouse. This disorder is cha racterized by convulsions induced by loud high-frequency sound and has been shown to be associated with increased nucleotide triphosphatase activity. (C) 1998 Academic Press.