FIG. 8.

AaGATAr represses gene transcription via GATA-specific recognition sites. The Drosophila Schneider cell line was transfected with the indicated plasmids by the lipid-mediated method. −, absence of substance; +, presence of substance. (A) Chloramphenicol acetyltransferase (CAT) activity from cells transfected with 100 μg of a reporter plasmid containing six copies of box A upstream of the Adh promoter driving the expression of CAT, with either 0.5 μg of pPac5-ABF (Drosophila GATAb isoform controlled by the actin promoter) or pAc5-AaGATAr (AaGATAr controlled by the actin promoter). As a control, the reporter plasmid Adh-1/CAT (lacking any GATA sequences) was used. (B) CAT activity from cells transfected with 100 ng of a reporter plasmid containing four copies of the AaVgGATAb binding site upstream of the Adh promoter driving the expression of CAT, with 0.5 μg of pPAc5-ABF or pAc5-AaGATAr. In all cases, cells were transfected for 12 h and incubated for 48 h at 22°C. The plasmid pAc5-LacZ was used in all assays for transfection efficiency. Transfection was performed in two independent experiments in triplicate. Significant differences (t test) between treated and respective controls are represented by asterisks (∗, P ≤ 0.05; ∗∗, P ≤ 0.005). Each value represents the mean ± standard deviation.