Two vesicle-associated membrane protein genes are differentially expressed in the rat central nervous system

Vesicle-associated membrane protein (VAMP) 1 is a 120-amino acid protein which co-purifies with cholinergic synaptic vesicles from the marine ray Torpedo californica. We used the Torpedo gene to isolate two independent classes of VAMP cDNA clones from rat brain. Nucleotide sequence analysis of the cDNAs predicts proteins which are 84 and 75% homologous to Torpedo VAMP-1. The amino-terminal 24-28 amino acid residues which comprise the proline-rich head are only about 50% homologous between the different VAMPs, yet the proline-rich character is maintained. The 69 amino acids which comprise the hydrophilic core are highly homologous to Torpedo VAMP-1, with only 2 amino acid substitutions in rat VAMP-1 and 6 in rat VAMP-2. The carboxyl-terminal 23 amino acids of all of the VAMP proteins maintain the hydrophobic character necessary to serve as a membrane anchor. Both VAMP transcripts are expressed differentially in the rat central nervous system. Whereas VAMP-2 is more highly expressed in the whole brain, VAMP-1 is expressed at a higher level in the spinal cord.