Fig. 2. The CSN is maternally deposited and is present until late embryogenesis. (A) Unfertilized eggs from virgin wild-type females were homogenized in gel-filtration buffer and total soluble protein was fractionated over a Superose 6 gel-filtration column (Pharmacia). Fractions (0.5 ml) were examined for the presence of CSN5 or CSN7 as indicated by immunoblot analysis with anti-CSN5 or anti-CSN7 affinity-purified antibodies. Positions of size markers are shown. (B) Proteins from csn5^null late-stage embryos (identified as non-kr-GFP) and heterozygote siblings (identified as kr-GFP positive) were analyzed for CSN5 and CSN7 as above.