TUF factor binds to the upstream region of the pyruvate decarboxylase structural gene (PDC1) of Saccharomyces cerevisiae

Summary The upstream activation site of the pyruvate decarboxylase gene, PDC1, of Saccharomyces cerevisiae contains an RPG box, and mediates the increase in expression of a PDC1-lacZ fusion gene during growth on glucose. Oligonucleotide replacement experiments indicate that the RPG box functions as an absolute activator of expression, but other elements (possibly CTTCC repeats) are required for carbon source regulation, and maximal expression. Gel retardation and oligonucleotide competition experiments suggest that the DNA binding factor TUF interacts with the RPG box in the upstream region of PDC1. Binding of TUF factor is not carbon source dependent in in vitro experiments, and is probably not responsible for glucose induction of PDC1 expression.     

Cis-acting elements essential for light regulation of the nuclear gene encoding the A subunit of chloroplast glyceraldehyde 3-phosphate dehydrogenase in Arabidopsis thaliana.

We report the characterization of cis-acting elements involved in light regulation of the nuclear gene (GapA) that encodes the A subunit of glyceraldehyde 3-phosphate dehydrogenase in Arabidopsis thaliana. Our previous deletion analyses indicate that the -277 to -195 upstream region of GapA is essential for light induction of the beta-glucuronidase reporter gene in transgenic tobacco (Nicotiana tabacum) plants. This region contains three direct repeats with the consensus sequence 5'-CAAATGAA(A/G)A-3' (Gap boxes). Our results show that 2-bp substitutions of the last four nucleotides (AA or GA) of the Gap boxes by CC abolish light induction of the beta-glucuronidase reporter gene in vivo and affect binding of the Gap box binding factor in vitro. We have also identified an additional cis-acting element, AE (Activation Element) box, that is involved in regulation of GapA. A combination of a Gap box trimer and an AE box dimer can confer light responsiveness of the cauliflower mosaic virus 35S promoter containing the -92 to +6 upstream sequence, whereas oligomers of Gap boxes or AE boxes alone cannot confer light responsiveness on the same promoter. These results suggest that Gap boxes and AE boxes function together as the light-responsive element of GapA.