Imprecise excision of the P{EP} element, resulting in a 4216bp deletion that begins 661bp upstream of the Mnn1 cDNA sequence and ends at the beginning of exon 4.
Although Mnn1e173 mutants are viable in control conditions, they show a high degree of lethality when subjected to heat shock, hypoxia, and oxidative stress. Mnn1e173/Df(2L)spdj2 show similar levels of lethality in response to heat shock.