Molecular characterization and expression of the gene for mouse NAD(+): arginine ecto-mono(ADP-ribosyl)transferase, Art1

Mono(ADP-ribosyl)transferases regulate the function of target proteins by a ttaching ADP-ribose to specific amino acid residues in the proteins. We hav e characterized the gene for mouse arginine-specific ADP-ribosyltransferase , Art1. Southern blot analyses indicate that Art1 is a single-copy gene. No rthern blot and reverse transcription-PCR analyses demonstrate prominent ex pression of Art1 in cardiac and skeletal muscle, and lower levels in spleen , lung, liver and fetal tissues. While human ART1 is not represented in the public expressed sequence tag (EST) database, the database contains 14 mou se Art1 ESTs. The Art1 gene encompasses four exons spanning 20 kb of genomi c DNA. The deduced amino acid sequence of Art1 exhibits the characteristic features of a glycosylphosphatidylinositol-anchored membrane protein. It sh ows 75-77% sequence identity with its orthologues from the human and rabbit , and 33-34% identity with its paralogues from the mouse, Art2-1 and Art2-2 . Separate exons encode the N- and C-terminal signal peptides, and a single long exon encodes the entire predicted native polypeptide chain. We expres sed Art1 in 293T cells as a recombinant fusion protein with the Fc portion of human IgG1. This soluble protein exhibits enzyme activities characterist ic of arginine-specific ADP-ribosyltransferases. The availability of the Ar t1 gene provides the basis for applying transgene and knockout technologies to further probe the function of this gene product.