Additional P{lacW} is inserted at nucleotide 6937, in the first coding exon. This maps to the first RNA binding domain.
Mutant females show 30% fertility. Overall structure of the ovaries is similar to that of wild type flies, but egg chambers with abnormal number of nurse cells are often detected.
Rbp9P2398 is rescued by Rbp9+t17.1
Remobilisation with Δ2-3 caused complete reversion of the mutant phenotype 7/34 times.