Fig. 1. Functional dissection of Eve, and functional rescue by Eve homologues. At the top is a diagram of Drosophila Eve protein domains (for details see Material and Methods). The HD and Gro interaction domain (LFKPY) are indicated. Flag-tagged modified Eve proteins were expressed using the eve rescue construct (from –6.4 kb to +8.6 kb) in a Df(2R)eve mutant background. Patterns of expression of en mRNA were monitored by in situ hybridization. (A) Rescue by tagged, wild-type Eve; note the equally spaced en stripes. (B) The same construct with the N domain removed (N); note that the spacing of en stripes is similar to wild type, although odd-numbered parasegments are slightly wider than even-numbered ones, indicating an increased activity. (C) The same construct with the R domain removed (R); odd-numbered parasegments are severely narrowed and some odd-numbered stripes are missing, indicating a severe, but not complete, loss of activity. (D) LFKPY-deleted Eve (C) (Kobayashi et al., 2001); the odd-numbered parasegments are narrowed, as in eve¹ mutants (E) at a semi-permissive temperature (18°C), indicating a partial loss of activity. (F) A chimera of the Eve HD and En repressor domains (H-En); both en stripes and parasegment spacing are rescued. (G) Tc-Eve (flour beetle); all en stripes are restored, but odd-numbered parasegments are slightly narrowed. (H) Sa-Eve (grasshopper); all en stripes are restored, but odd-numbered parasegments are narrower. (I) Mouse Evx1; en stripes are restored, but spacing is abnormal, due to a combination of increased protein stability and variations in expression among the early stripes (Evx1 stripes 4, 5, and 6 are weak, and the corresponding parasegments, 7, 9 and 11, are narrowed, see text).