Fig. 2.

Both brL and brE are required for dorsal appendage formation. (A–C) The effects of brL and brE on eggshell morphogenesis were assayed using RNAi-mediated down-regulation of br transcript. The bars summarize appendage phenotypes scored before and after temperature shift. (A) Down-regulation of BR by brL only compromised appendage formation. Upon transfer to 29 °C, the percentage of eggshells with shortened or absent dorsal appendages increased from 31%, to 60% and 55% after 1 and 2 d, respectively (n = 560 eggs). (B and B′) Down-regulation of BR by brE produced loss of chorionic imprints in the posterior and ventral regions of the eggshell (three samples with different degrees of severity shown), and eventually loss of eggshell integrity after 2 d at 29 °C. (C) Down-regulation of BR by brE also compromised appendages formation, with an increase from 8%, to 21% and 73% after 1 and 2 d at 29 °C, respectively (n = 2,508 eggs). (D) The described eggshell malformations were clearly different from those produced when the brE-Gal4, brL-Gal4, and UAS-br-RNAi (each in combination with tub-Gal80^ts) were assayed on their own (n = 1,464, 1,183, 913, respectively). (E–F′′′) Immunostaining for GFP (green), β-GAL (red), and BR (gray) of stage 10B egg chambers carrying either brE-LacZ or brL-LacZ reporters. Expression of br-RNAi is marked by GFP. The yellow outlines highlight clone boundaries. (E–E′′′) Loss of BR does not affect brE expression (n = 26 egg chambers). (F–F′′′) Loss of BR down-regulates brL (n = 25 egg chambers).