The carbon metabolism‐controlled Synechocystis gap2 gene harbours a conserved enhancer element and a Gram‐positive‐like −16 promoter box retained in some chloroplast genes

Abstract

The two glyceraldehyde‐3‐phosphate dehydrogenase‐encoding genes (gap) of Synechocystis were shown to be expressed as monocistronic transcripts. Whereas gap1 expression is slow and weak, gap2 gene induction is rapid and strong. Transcription of the gap2 gene was shown to depend on functional photosynthetic electron transport and on active carbon metabolism. The basal promoter of gap2 (P, −45 to +34, relative to the transcription start site) is controlled by three cis‐acting elements designated A (−443 to −45), B (+34 to +50, in the untranslated leader region) and C (+50 to +167, in the coding region) that, together, promote a 100‐fold stimulation of P activity. Element B was found to behave as a transcriptional enhancer, in that it was active regardless of its position, orientation and distance relative to P. All three cis‐acting stimulatory elements exhibit a common 5′‐agaTYAACg‐3′ nucleotide motif that appears to be conserved in cyanobacteria and may be the target for a transcriptional enhancer. We also report that gap2 transcription depends on a Gram‐positive‐like −16 promoter box (5′‐TRTG‐3′) that was obviously conserved throughout the evolution of chloroplasts. This is the first report on the occurrence of a −16 promoter element in photoautotrophic organisms.

A PP2C-type phosphatase dephosphorylates the PII signaling protein in the cyanobacterium Synechocystis PCC 6803

“…Furthermore, a hexamer (TTGTAA) resembling the Ϫ35 promoter box can be found 27 bp upstream of the Ϫ10 element. A 29-bp spacing between the Ϫ10 and Ϫ35 boxes has been described in Synechocystis promoters recently (33). From this it appears that pphA is transcribed monocistronically from a promoter, which is located within the 3Ј end of the preceding ORF sll1770.…”

The 5′-upstream cis-acting sequences of a cyanobacterial psbA gene: analysis of their roles in basal, light-dependent and circadian transcription

“…Cyanobacterial and higher-plant psbA genes share homology in the promoter sequence (Shibato et al 1998). The influence of the sequence and the spacing of the promoter elements on transcription in cyanobacteria has been investigated using the genes secA (SecA is involved in the transport of proteins) and gap2 [coding for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in the Calvin cycle; Mazouni et al 1998;Figge et al 2000]. However, few attempts have been made to identify the nucleotides in the cyanobacterial psbA promoter that are necessary for transcription in cyanobacteria.…”

Pleiotropic Effect of a Histidine Kinase on Carbohydrate Metabolism in Synechocystis sp. Strain PCC 6803 and Its Requirement for Heterotrophic Growth

“…The glycolytic genes studied to date in some detail include glucose-6-phosphate dehydrogenase (G6PD) (21,22), 6-phosphogluconate dehydrogenase (6PGD) (2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (5,12,29), pyruvate kinase (11), phosphoenolpyruvate carboxylase (15), fructose-1,6-bisphosphate aldolase (FBA) (17), and phosphofructokinase (PFK) (18,28). Furthermore, regulation of dark carbon metabolism and its coordinated control in cyanobacteria are still poorly understood.…”