Functional Mapping of the Mouse Hairless Gene Promoter Region

The study focused on the mouse hairless gene (Hr), which is crucial for hair follicle function and when absent, leads to irreversible hair loss. Researchers identified the transcriptional initiation start site of the Hr gene and discovered a new 1.1 kb cis-control element (RE1) that includes the promoter region and can drive expression in skin and brain cell lines. Through deletion analysis and exploration of regulatory motifs, they found that a thyroid hormone response element (TRE) located 300 bp from the cap site is essential for gene expression in skin and brain cells, while a vitamin D response element (VDRE) 94 bp upstream of the TRE specifically modulates expression in skin cells. Additionally, a new cis-regulatory motif (UE60) was identified at the 5’-end of RE1, which likely interacts with both TRE and VDRE. These findings suggest a complex molecular network involving several signalling pathways in hair follicle formation and indicate a potential autoregulatory pathway in Hr gene regulation. The study enhances understanding of the regulatory mechanisms of the Hr gene, with implications for hair follicle biology and hair loss disorders.