Deletion of the Sox21 gene drastically affects hair lipids.

The effects of Sox21 gene deletion on hair lipids have been studied. For the cuticle-specific bound lipid 18-methyl eicosanoic acid (18- MEA), which was found to predominantly exist as the free form in Sox21^−/− hair, total levels and distribution were unexpectedly unchanged. This indicates that while the biosynthesis of 18- MEA is unaffected, its covalent attachment to the cuticle surface is disrupted by loss of keratin-associated protein binding partners. Although the class compositions differed, the total ceramide ( CER) levels were found to be comparable between Sox21^+/+ and Sox21^−/− hairs. Deletion of the gene was also found to increase cholesterol sulphate ( CS) levels. The biosynthesis process might be associated with cuticle keratinocyte maturation, because both CS and CERs are known bioactives in keratinocyte differentiation. [ABSTRACT FROM AUTHOR]