In order to obtain the specific genes of snailfish a subtracted cDNA library was constructed, and analysed by sequencing and GenBank search. Among them C90-171 clone was turned out to be genes showing low homology and nonredundant genes. This novel clone was named Gomsin(C90-171). Gomsin was shown to be intensely expressed in the epithelial cells, some mesenchymal cells, and sheaths of muscle bundles in the result of immunohistochemistry. In the cross reaction assay of Gomsin antibody against various human tissues, the Gomsin was strongly expressed in the ductal and acinar cells of salivary glands, which was similar to the expression patterns of proline-rich proteins(PRPs) of human. The antibody raised against the Gomsin was clearly cross-reacted with human salivary PRPs and also recombinant proteins of human PRPs in the Western blot and immunoprecipitation analysis. Contrast to the salivary PRPs, the Gomsin was not easily degraded in the mixed saliva, but rapidly attacked on the cultured keratocytes in vitro. The simulated protein structure of Gomsin was similar to the whorled pattern of PRPs, even though the amino acid sequence of Gomsin was quite different from those of PRPs. These data suggest that the Gomsin is a characteristic matrix protein in the skin and body of snailfish, which is also utilized for the tissue protection in the similar way to the PRPs of human muco-secretory organs.