Figure 1
Purification and assays of mutant maleless (MLE) proteins. (A) Domain structure of the mutant MLE proteins. (B) Silver staining of purified Flag-tagged recombinant MLE proteins from S2 cells expressing the different transgenes run in a 7.5% SDS-polyacrylamide gel. (C) Results of ATPase and helicase assays of MLE proteins. Upper panel: helicase activity measured as a function of single-stranded RNA released from the double-stranded RNA/DNA substrate; lower panel: ATPase activity measured as a function of inorganic phosphate (Pi) released from radioactive ATP. The activity of wild-type MLE is set at 100%, and the error bars are the SD from the mean of three assays. (D) Expression of Flag-tagged wild-type and mutant MLE proteins in transgenic flies in a null endogenous mle gene background (mle1). Western blots of crude lysates from adult fly heads developed with anti-Flag antibodies (top panel), with anti-H3 antibodies as a loading control (bottom panel). Similar results were obtained with three independent lines of each transgene used for immunofluorescence and rescue experiments.