Mutations at the suppressor of forked locus increase the accumulation of gypsy-encoded transcripts in Drosophila melanogaster.

We studied the effect of mutations at the suppressor of forked [su(f)] locus in Drosophila melanogaster on the accumulation of transcripts encoded by the gypsy transposable element. Mutations at this locus do not affect the pattern of developmental expression of gypsy, but they cause an increase in the total amount of gypsy RNA present at different stages of development as compared with wild-type or su(f)/+ flies. These results suggest that the su(f)-encoded products acts as a negative regulator of gypsy expression.