Figure 1.

Midgut Length in Different nub Mutants during Adult Stages

(A) Schematic structure of the Drosophila nub gene. The nub gene contains seven exons, as depicted with boxes, and transcription is initiated at two separate promoters (arrows). Exons and introns (solid black line) are drawn to scale, except for the large intron between exon 2 and 3 (dashed line), which is reduced in size.

(B) Organization of Nub-PB and Nub-PD proteins encoded by the nub gene. Note that Nub-PB protein contains three unique exons (1, 2, and 3) while Nub-PD protein contains one unique exon (4). The shared three exons (5, 6, and 7) contain the coding sequence for the DNA-binding POU_S and POU_H domains (orange). Filled black triangle indicates the nub-RB gal4 insertion site and black bold line shows the position of the nub-RD-gal4 enhancer line. Two nub mutants, nub¹; 412 transposable element insertion site indicated by a dashed triangle in (A) and nub^E37 (an EMS-induced null mutant for both Nub-PB and Nub-PD; Yeo et al., 1995) are used in this work.

(C) Midguts from 21-day-old control (top), nub¹/nub¹ (middle), and nub¹/+; nub^E37 (bottom) flies.

(D) Measurement of midgut lengths in 5-day-old (circle) and 21-day-old (triangle) flies. Statistical significance was calculated using two-way ANOVA, Tukey's multiple comparisons test, ^∗∗p < 0.01, ^∗∗∗∗p < 0.0001. n = 13–21 guts. Error bars represent SEM.