Fig. 4. Deadenylation of nos mRNA by CCR4 contributes to its translational repression. (A) Immunostaining of embryos with anti-Nos antibody during the first hours of embryogenesis. The increase in amounts of Nos protein was visible in bulk embryos from twin^KG877/Df(3R)crb-F89-4 and twin¹²²⁰⁹/Df(3R)crb-F89-4 females. twin mutant females were crossed with identical males and smg¹/Df(Scf^R6) females were crossed with wild-type males. (B-D) Cuticle preparations of embryos showing strong head defects. (B) Wild type. (C,D) Embryos from twin¹²²⁰⁹/Df(3R)crb-F89-4 females crossed with wild-type males; (C) head replaced by a hole; (D) no head structures. Anterior is oriented toward the left.