Frequent Imprecise Excision among Reversions of a P Element-Caused Lethal Mutation in Drosophila.
RpII215(D) (50) (= D50) is a lethal mutation caused by the insertion of a 1.3-kb P element 5' to sequences encoding the largest (215 kilodaltons) subunit of Drosophila RNA polymerase II. In dysgenic males D50 reverted to nonlethality at frequencies ranging from 2.6 to 6.5%. These reversions resulted from loss of P element sequences. Genetic tests of function and restriction enzyme analysis of revertant DNAs revealed that 35% or more of the reversion events were imprecise excisions. Two meiotic mutations that perturb excision repair and postreplication repair (mei-9(a) and mei-41(D5), respectively) had no influence on reversion frequency but may have increased the proportion of imprecise excisions. We suggest that these excisions are by-products of, rather than intermediates in, the transposition process.
Voelker
R A
RA
Laboratory of Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.
Greenleaf
A L
AL
Gyurkovics
H
H
Wisely
G B
GB
Huang
S M
SM
Searles
L L
LL