TM7XN1, a novel human EGF-TM7-like cDNA, detected with mRNA differential display using human melanoma cell lines with different metastatic potential

We have identified a novel 384 bp cDNA differentially expressed in a human melanoma metastasis model. Northern blot analysis showed expression in the poorly and intermediately metastasizing cell lines and a marked downregulat ion in the highly metastatic cell lines. Using RT-PCR expression was also s een in several other tumor cell lines and normal cell types of human origin . cDNA sequence analysis revealed an ORF of 687 amino acids containing seve n putative transmembrane domains C-terminally and a long N-terminus, The ge ne was mapped to 16q13. Highest homology was observed with members of the E GF-TM7 subfamily of the secretin/calcitonin receptor family, We propose the delineation of a subfamily of TM7 proteins, LN-TM7, containing seven trans membrane proteins with a long N-terminal extracellular part. (C) 1999 Feder ation of European Biochemical Societies.