Transcriptional Activation of a Subset of Hair Keratin Genes by the NF-κB Effector p65/RelA

The study investigated the role of the NF-κB effector p65/RelA in the transcriptional activation of hair keratin (HK) genes. Using transient transfections and reporter assays in tissue culture cells, the researchers found that p65/RelA induces the transcription of several HK genes, particularly acidic hair keratin 5 (Ha5). They identified major NF-κB/RelA binding sites in the regulatory region of the Ha5 gene and confirmed p65's direct binding through gel shift assays. Immunohistochemistry on human hair follicle sections showed co-expression of p65 with HKs in the hair shaft compartment, suggesting that p65 mediates NF-κB pathway activity in hair formation. This discovery provided new insights into the molecular mechanisms of hair formation and potential implications for ectodermal dysplasias.