CHARACTERIZATION OF BOVINE AND HUMAN CDNAS ENCODING NAP-22 (22 KDA NEURONAL TISSUE-ENRICHED ACIDIC PROTEIN) HOMOLOGS

We have characterized the bovine and the human cDNAs encoding the NAP- 22 (22 kDa neuronal tissue-enriched acidic protein) homologs, Both bov ine and human cDNAs encode proteins of 227 amino acids, The deduced am ino acid sequences of the bovine and the human proteins are 63% and 65 % identical, respectively, to that of rat NAP-22 protein, strongly sug gesting that both the cDNAs characterized encode NAP-22 proteins. They also share 45% and 41% amino acid sequence identities with chicken CA P-23 (23 kDa cytoskeleton associated protein). Several important prote in motifs, including myristoylation and phosphorylation sites, are wel l conserved in sequences and positions in all three mammalian NAP-22 p roteins and chicken CAP-23 proteins. The bovine cDNA was characterized further. Southern analysis of the bovine genomic DNA suggests that th e bovine NAP-22 protein is encoded by a single-copy gene. RNA blot ana lysis revealed that the bovine gene for NAP-22 protein encodes a 1.7 k b transcript that is present only in the brain. Our data suggest that the four proteins, bovine and human NAP-22 homologs, rat NAP-22, and c hicken CAP-23, have homologous functions in different organisms.