Fig. 1. CSN5 expression in wild-type and CSN5 mutants. (A,B) In wild-type ovaries, CSN5 expression is detected in nurse cells beginning in the germarium. (C,D) In CSN5^L4032-mutant germline clones (GLC), expression of CSN5 RNA is strongly reduced. Northern blot analysis of ovarian extracts show a similar reduction in CSN5 GLC (data not shown). (E) Expression in early wild-type embryos indicates a strong maternal contribution. (F) In CSN5 heterozygotes that lack maternal CSN5 RNA, zygotic expression is detectable in an anterior stripe during cellular blastoderm (arrow). (G,H) During gastrulation CSN5 RNA is most strongly expressed in the ventral furrow, the cephalic furrow, and both the anterior and posterior midgut invaginations. This expression pattern is absent in maternal and zygotic minus embryos (data not shown). All figures show anterior towards the left. (I) Western blot of wild-type and CSN5-mutant ovarian extracts. A single 37-38 kDa band seen in wild-type ovaries was strongly reduced in CSN5^L4032 GLC ovaries. Its size is consistent with the predicted size for Drosophila CSN5 (37 kDa) and no other specifically reduced bands were detected. Heteroallelic combinations of CSN5^L4032 with excision derivatives show a gradation of CSN5 protein that correlates with their allelic strength determined from viability, eggshell phenotypes and northern blots.