Isolation and characterization of a gene specifically expressed in different metastatic cells and whose deduced gene product has a high degree of homology to a Ca2+-binding protein family.

The gene mts1, which is expressed specifically in metastatic cells, was isolated by molecular cloning coupled with differential DNA reassociation. Transcription of mts1 was found not only in tumor cells, but also in normal cells; homologous RNA was detected only in spleen, thymus, bone marrow, and blood lymphocytes. DNA sequencing of mts1 revealed an open reading frame containing information for a peptide of 101 amino acids, and the amino acid sequence suggested that the mts1 protein was identical to the previously isolated Ca2+-binding mouse protein (Jackson-Grusby et al. 1987; Goto et al. 1988). Thus, the mts1 protein is a member of the calcium-modulated protein family, and our data indicate that mts1 is involved in regulating the metastatic behavior of tumor cells.