Scd3 -: A novel gene of the stearoyl-CoA desaturase family with restricted expression in skin

Stearoyl-coenzyme A (CoA) desaturase (SCD) is a key enzyme involved in the conversion of saturated fatty acids into monounsaturated fatty acids. Previously, two members of this gene family namely, Scdl and Scd2, have been reported. Here we report the identification and characterization of a novel member of this family, Scd3, whose expression is restricted to mouse skin, specifically to the sebaceous gland. The Scd2 gene codes for a transcript of similar to4.9 kb with an open reading frame that results in a 359-amino-acid protein, Scd3 shares 91 and 88% identity in the protein-coding region with Scdl and Scd2, respectively, and maps to mouse chromosome 19 in very close proximity to Scd1 and Scd2. Unlike Scd1, Scd3 expression is higher in male mouse skin than in female mouse skin. The promoter sequence of Scd3 reveals similarity with Scdl in the proximal region but also possesses several distinctive features including the polyunsaturated fatty acid-response element. Scd3 is expressed in the skin of young asebia mutant mice (SCd1(ab2J)/ Scd1(ab2J)) in the absence of Scd1. Scd3 expression changes during the mouse hair cycle but not as dramatically as Scd1. The tissue-specific and sex-dependent expression of Scd3 suggests the presence of gene- and hormonal-specific control mechanisms. (C) 2001 Academic Press.