This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Casey, E S Articles by Grossman, A Search for Related Content PubMed PubMed Citation Articles by Casey, E S Articles by Grossman, A

 Previous Article  |  Next Article 

J Bacteriol. 1994 October; 176(20): 6362-6374

research-article

In vivo and in vitro characterization of the light-regulated cpcB2A2 promoter of Fremyella diplosiphon.

Department of Biological Sciences, Stanford University, California.

ABSTRACT

When exposed to different spectral qualities of light, many cyanobacteria dramatically alter their phycobilisome rod composition in a process termed complementary chromatic adaptation. In the cyanobacterium Fremyella diplosiphon, this response is associated with differential expression of the cpcB2A2, cpeBA, and cpeCDE operons, which code for the phycobiliproteins phycocyanin and phycoerythrin and the phycoerythrin linker polypeptides, respectively. To define components of the signal transduction pathway involved in light-regulated expression of genes encoding phycobilisome polypeptides, we have used in vivo and in vitro techniques to identify cis-acting sequences and trans-acting factors necessary for the regulation of the red-light-inducible cpcB2A2 operon. Deletion of the cpcB2A2 upstream sequences to -76 bp with respect to the transcription start site had no effect on red-light induction of a cpcB2A2-beta-glucuronidase (GUS) chimeric gene, while deletion to -37 bp abolished GUS expression. Furthermore, a fragment of the cpcB2A2 gene from -76 to +25 bp linked to the untranslated leader of cpcB1A1 (a constitutively expressed operon encoding phycocyanin) is sufficient to drive high-level GUS expression in red light. Therefore, the sequence between positions -76 and -37 is necessary for the expression of cpcB2A2, and the region extending from -76 to +25 is sufficient for red-light induction of the operon. Attempts were made to correlate the in vivo data with protein binding in the region upstream of the transcription start site of cpcB2A2. Using in vitro analysis, we detected two protein-binding sites in the cpcB2A2 promoter which were localized to positions -162 to -122 and -37 to +25. Proteins from both red- and green-light-grown cells interacted with the former site, while only proteins present in extracts from red-light-grown cells interacted with the latter site. The data from both the in vivo and in vitro analyses suggest that while two regions upstream of the cpcB2A2 transcription initiation site specifically bind proteins, only the binding site bordering the transcription start site is important for complementary chromatic adaptation.

This article has been cited by other articles:

• Tu, C.-J., Shrager, J., Burnap, R. L., Postier, B. L., Grossman, A. R. (2004). Consequences of a Deletion in dspA on Transcript Accumulation in Synechocystis sp. Strain PCC6803. J. Bacteriol. 186: 3889-3902 [Abstract] [Full Text]  
• Grossman, A. R., Bhaya, D., He, Q. (2001). Tracking the Light Environment by Cyanobacteria and the Dynamic Nature of Light Harvesting. J. Biol. Chem. 276: 11449-11452 [Full Text]