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Fig. 6. MBF1 participates in the TDF-dependent activation. (A) Colocalization of
TDF and MBF1 to the transgenic reporter TDS-lacZ on the polytene
chromosome. Salivary gland polytene chromosomes were prepared from a third
instar larva of a sgP[Gal4]; UAS-tdf, TDS-lacZ/+; P[FLAG-MBF1]/+ line
(4-6) or the same line without TDS-lacZ (1-3) and stained with
anti-TDF (2 and 5) and anti-FLAG (1 and 4) antibodies. Blue signals represent
DAPI staining. Panels 3 and 6 show the merged signals. The arrow marks the
locus harboring the TDS-lacZ transgene. (B) MBF1 is required for full
activation by TDF in vivo. Extracts were prepared from stage 16 embryos of the
indicated lines and their ß-galactosidase activities were measured. Shown
are average specific activities of six independent assays with standard
errors.