Deletion of a 1.6kb ApaI fragment spanning the carboxy terminal half of Irbp, amino acids 266-631.
IrbpΔ is a non-suppressor of female sterile phenotype of BlmD3/BlmD2
IrbpΔ is a non-suppressor of chemical sensitive phenotype of BlmD3/BlmD2
Fails to rescue the female sterility and MMS sensitivity of mus309 mutants.