A Novel Human Type I Hair Keratin Gene: Evidence For Two Keratin HHa3 Isoforms

The study identified a novel human type I hair keratin gene, hHa3, which was found to have two isoforms, hHa3-I and hHa3-II. This discovery was based on nucleotide and amino acid sequence analysis, revealing differences in 24 amino acid positions compared to a previously described hHa3 keratin. The research involved PCR amplification of genomic DNA from 25 normal human subjects, resulting in two distinct products due to unique intron 6 sequences, indicating separate genes for each keratin species. Southern blot analyses confirmed that both keratin genes are present as single copy sequences in the human genome. This work provided evidence for the existence of two distinct isoforms of the hHa3 keratin gene.