Consists of a fragment encoding a deleted form of ref(2)P (amino acids 92-599, numbering relative to the sequence of ref(2)P+++.O1.cCMa, are deleted). The PB1 domain contains '+' sequences that are derived from ref(2)Po2 at the d, p and p' polymorphic locations.
ref(2)P+++.Δ92-599.cCMa is permissive for sigma virus multiplication.
ref(2)P+++.Δ92-599.cCMa fails to rescue ref(2)Pod3/Df(2L)E55
ref(2)Pod3/Df(2L)E55 males carrying ref(2)P+++.Δ92-599.cCMa are sterile.