Fig. 2. Alanine mutations at residues 52-56 of full-length Bcd increase its activity. (A) Wild-type Bcd and Bcd(A52-56), which contains five alanines at positions 52-56 of full-length Bcd. HD, homeodomain. (B) CAT assay results from S2 cells that were transfected with increasing amounts of effector plasmids expressing wild-type Bcd or Bcd(A52-56): 0.2 µg (lanes 2, 6), 0.5 µg (lanes 3, 7), 1.0 µg (lanes 4, 8), 2.0 µg (lanes 5, 9). Lane 1 shows the result from cells transfected with an empty vector expressing no Bcd. All CAT reactions shown here were carried out in 30 minutes. (C) A plot of CAT activities against the amount of the transfected effector DNA. To measure accurately the activity difference between the proteins, a shorter length of the CAT reaction time was used for the mutant protein (also see legend to Fig. 1). (D) Western blot analysis showing the total amount of Bcd proteins in transfected cells. The amount of transfected DNA is the same as in B.