A genomic fragment containing His2Av coding and flanking sequences (BDGP R6 chr3R: 26,866,577-26,869,660) containing amino acid replacements K120R and K121R to prevent ubiquitylation.
His2Av2K-2R mutants (in which the His2Av gene has been replaced with His2Av2K-2R) are viable and fertile with no obvious morphological defects.