Regulation of a Hair Follicle Keratin Intermediate Filament Gene Promoter

The study investigated the regulation of the wool keratin intermediate filament gene K2.10 promoter during hair growth. Researchers identified that the region spanning nucleotides –350 to +53 was crucial for directing gene expression in the follicle cortex of transgenic mice. Deleting nucleotides –350 to –150 resulted in a loss of promoter activity, while a mutation at the LEF-1 binding site decreased activity but maintained specificity. DNase I footprinting and electrophoretic mobility shift assays revealed that, besides LEF-1, Sp1, AP2-like, and NF1-like proteins also bound to the promoter, with Sp1 and AP2-like proteins flanking the LEF-1 site and NF1-like proteins binding near the transcription start site. The study concluded that the LEF-1 binding site acted as an enhancer element, with other factors contributing to tissue- and differentiation-specific regulation of the promoter.