Fig. 1.
Phosphorylation of recombinant Knirps protein in Drosophila embryos. FLAG-tagged Knirps protein was expressed in 2–4 hour Drosophila embryos and lysates were analyzed by Western blot. Before heat-shock induction, no specific band is visible (lane 1). After heat shock, a set of bands from 60–80 kDa is visible (arrow, lane 2). These bands collapse to a single species upon incubation of lysates with increasing amount of lambda phosphatase (lanes 3–7), but not in the presence of the phosphatase inhibitor sodium orthovanadate (lanes 8–9). A nonspecific product is marked with the asterisk.