Genetically Separable Determinants of Hair Keratin Gene Expression

The study identified and characterized a novel nude allele, nu(StL), which encoded a truncated Whn transcription factor lacking the activation domain but retaining the DNA binding domain. This allele resulted in impaired expression of several hair keratin genes in a pattern similar to the previously described Whn(nu) mutant, although a significant difference was observed in the expression of mHa5, which was reduced in nu(StL)/nu(StL) but not in nu/nu mice. The study demonstrated that the mutant Whn protein in nu/nu mice could not enter the nucleus, whereas in nu(StL)/nu(StL) mice, it was present in the nucleus. The findings highlighted the complexity of transcriptional control mechanisms of hair keratin genes and suggested that mutations in the Whn gene could have different molecular consequences.