Expression of the ubiquitin-conjugating DNA repair enzymes HHR6A and B suggests a role in spermatogenesis and chromatin modification

The Saccharomyces cerevisiae RAD6 protein has been previously identified as an important component of the 'N-rule' protein breakdown pathway and in meiotic recombination. Cloning and expression of the human homologs of the RAD6 gene, designated HHR6A and HHR6B, revealed a highly conserved structure. However, UV induction in yeast was not preserved, indicating differences in the regulation of expression of these genes between yeast and mammals. Genetic analyses showed that HHR6 proteins are localized in euchromatin areas, suggesting their involvement in chromatin formation and spermatogenesis.