Gene characterization of sciellin (SCEL) and protein localization in vertebrate epithelia displaying barrier properties

Sciellin is a precursor of the cornified envelope of mammalian stratified e pithelia characterized by a central core of nonidentical repeats. We charac terized the genomic structure of human sciellin and showed that each homolo gous repeat was encoded by one exon. We also characterized mouse sciellin a nd showed that mouse sciellin and human sciellin (HGMW-approved symbol SCEL ) share a similar gene organization and protein expression pattern. This on e exon/one repeat organization is unique among other cornified envelope pre cursors characterized by homologous repeats. me identified an alternatively spliced isoform of human sciellin, absent in mouse, characterized by an ad ditional repeat at the beginning of the core domain. During embryonic devel opment, the accumulation of sciellin transcript and the accumulation of sci ellin protein in the epidermis correlated with the activation of markers of terminal differentiation in epidermis. Mouse sciellin was also identified in simple epithelia with barrier properties, lending further support to its importance in epithelial function, (C) 2000 Academic Press.