Figure 1.

Drosophila embryos deficient in TAF_IIs or TBP are impaired for dl-dependent transcription of sna. Whole mount in situ hybridization of stage 5 Drosophila embryos with digoxigenin-UTP-labeled anti-sense RNA probe to sna (A–D) or lacZ gene (E and F) are shown. All embryos are oriented with anterior to the left and ventral surface facing the reader. Female flies with different genotypes were crossed to wild-type males (A–D) or wild-type males carrying a 1.6-kilobase sna-lacZ transgene (E and F) (19). (A) sna expression pattern in embryos from dl/+ mothers. (B) sna expression in dl/+; Df(3)TAF110/+ maternal background. There is a slight narrowing in the pattern, particularly in the cephalic furrow region. (C) sna expression in dl/+; Df(3)TAF_II60/+ maternal background. A similar but milder effect is seen. (D) In dl/Df(2)TBP maternal background, the majority of the embryos are severely affected. (E and F) The 1.6-kilobase snail-lacZ transgene directs an abnormal expression pattern in embryos derived from dl/+ females (E); however, it directs a normal expression in embryos Df(2)TBP/+ from females (F).