MRNA expression of membrane-fusion-related proteins in rat parotid gland

The soluble N-ethylmaleimide-sensitive fusion (NSF) attachment protein (SNA P) receptor (SNARE) hypothesis has been applied to exocytosis in salivary g lands. The expression of SNARE proteins has not been well investigated in t he parotid gland. In this study, the mRNA expression of SNAREs and membrane -fusion-related proteins were investigated in the rat parotid by reverse tr anscriptase-polymerase chain reaction (RT-PCR). All syntaxins except syntax in 1, and the vesicle-associated membrane proteins (VAMP) except VAMP-7, NS F, SNAP-23 and alpha -SNAP, were expressed for the SNAREs in rat parotid. S ynaptotagmins 3, 4 and 11, Munc18s (1, 2 and 3), syncollin, prenylated Rab acceptor (PRA1), zygin 1, pantophysin and cellugyrin, which are the other m embrane-fusion-related proteins, were also detected, but neither Rim nor ra bphilin 3A, which have high specificity of binding to Rab 3A, were found. m RNA expressions of many SNAREs and of the membrane-fusion-proteins suggest novel interactions for the regulation of salivary exocytosis. (C) 2001 Else vier Science Ltd. All rights reserved.