EPIDERMAL SURFACE-ANTIGEN (MS17S1) IS HIGHLY CONSERVED BETWEEN MOUSE AND HUMAN

A mouse monoclonal antibody ECS-1 raised to human keratinocytes detect s a 35-kDa epidermal surface antigen (ESA) and causes keratinocyte dis sociation in vitro. ECS-1 stains skin of 16-day mouse embryo and 8- to 9-week human fetus, Mouse Esa cDNA encodes a 379-amino-acid protein t hat is 99.2% identical to the human, differing at only 3 amino acids. The gene (M17S1) was mapped to mouse chromosome 11, highlighting the c onserved linkage synteny existing between human chromosome 17 and mous e chromosome 11. Although the nude locus has been mapped to the same r egion of chromosome 11, no abnormalities in protein, mRNA, or cDNA or genomic sequences were detected in nude mice. However, both nude and c ontrol mice were found to have a second Esa mRNA transcript that conse rves amino acid sequence and molecular weight. The mouse and human 5' and 3' untranslated sequences are conserved, Similar RNA folding patte rns of the 5' untranslated region are predicted despite a 91-bp insert ion in the mouse. These data suggest that both the function and the re gulation of ESA protein are of importance and that Esa (M17S1) is not the nude locus gene. (C) 1995 Academic Press, Inc.