Fig. 2. CCR4 and Smg are required for nos mRNA deadenylation and degradation. (A) PAT assays and RT-PCR of nos mRNA showing its deadenylation and destabilization in the wild type and its stabilization in twin mutants during early embryogenesis. Females of the indicated genotypes were crossed with identical males. Note that, consistent with both maternal and zygotic contributions to mRNA destabilization in early embryos (Bashirullah et al., 1999), we found that embryonic lethality increased when twin females were crossed with males of the same genotype instead of wild-type males [e.g. 94% embryonic lethality (n=468) from a cross between twin¹²²⁰⁹ homozygous females and males]. Df is Df(3R)crb-F89-4. RNAs were from embryos spanning 1 hour intervals. The sop mRNA (bottom panels) was used as a control in A and B. (B) PAT assays of nos mRNA showing its stabilization with long poly(A) tails in smg mutants or from a nos transgene lacking the TCE. nos^BN is a null mutant that does not produce nos RNA. Females of the indicated genotypes were crossed with wild-type males. RNA was prepared from the time intervals indicated. (C) In situ hybridizations revealing nos mRNA in embryos. twin^KG877/Df(3R)crb-F89-4 females were crossed with identical males and smg¹/Df(Scf^R6) females were crossed with wild-type males. Anterior is oriented toward the left.