Structure, chromosomal localization, and expression of the gene for mouse ecto-mono(ADP-ribosyl)transferase ART5

Mono (ADP-ribosyl) transferases regulate the function of target proteins by attaching ADP-ribose to specific amino acid residues in their target prote ins. The purpose of this study was to determine the structure, chromosomal localization, and expression profile of the gene for mouse ecto-ADP-ribosyl transferase ART5. Southern blot analyses indicate that Art5 is a single cop y gene which maps to mouse chromosome 7 at offset 49.6 cM in close proximit y to the Art1, Art2a and Art2b genes. Northern blot and RT-PCR analyses dem onstrate prominent expression of Art5 in testis, and lower levels in cardia c and skeletal muscle. Sequence analyses reveal that the Art5 gene encompas ses six exons spanning 8 kb of genomic DNA. The 5' end of the Art5 gene ove rlaps with that of the Art1 gene. A single long exon encodes the predicted ART5 catalytic domain. Separate exons encode the N-terminal leader peptide and a hydrophilic C-terminal extension. Sequencing of RT-PCR products and E STs identified six splice variants. The deduced amino acid sequence of ART5 shows 87% sequence identity to its orthologue from the human, and 37 and 3 2% identity to its murine paralogues ART1 and ART2, Unlike ART1 and ART2, A RT5 lacks a glycosylphosphatidylinositol-anchor signal sequence and is pred icted to be a secretory enzyme. This prediction was confirmed by transfecti ng an Art5 cDNA expression construct into Sf9 insect cells. The secreted ep itope-tagged ART5 protein resembled rat ART2 in exhibiting potent NAD-glyco hydrolase activity. This study provides important experimental tools to fur ther elucidate the function of ART5. (C) 2001 Published by Elsevier Science B.V.