Functional Elements of the Strong <i>psbAI</i> Promoter of <i>Synechococcus elongatus</i> PCC 7942

• Usha Nair

  <!--label omitted: 1-->Department of Biology, Texas A&M University, College Station, Texas 77843-3258

• Colleen Thomas

  <!--label omitted: 1-->Department of Biology, Texas A&M University, College Station, Texas 77843-3258

• Susan S. Golden

  <!--label omitted: 1-->Department of Biology, Texas A&M University, College Station, Texas 77843-3258

抄録

The psbAI gene of the cyanobacterium Synechococcus elongatus PCC 7942 is one of three psbA genes that encode a critical photosystem II reaction center protein, D1. Regulation of the gene family in response to changes in the light environment is complex, occurs at transcriptional and posttranscriptional levels, and results in an interchange of two different forms of D1 in the membrane. Expression of psbAI is downregulated under high-intensity light (high light) in contrast to induction of the other two family members. We show that, in addition to a known accelerated degradation of the psbAI message, promoter activity decreases upon exposure to high light. Unlike the other psbA genes, additional sequences upstream of the psbAI −35 element are required for expression. Mutagenizing the atypical psbAI −10 element from TCTCCT to TATAAT increased the magnitude of expression from both psbAI :: lacZ and psbAI :: luxAB fusions but did not affect downregulation under high light. Inactivation of group 2 sigma factor genes rpoD2 and sigC , in both wild-type and −10-element mutagenized backgrounds, resulted in elevated psbAI :: luxAB expression but did not alter the response to high light. The results are consistent with redundancy of promoter recognition among cyanobacterial group 2 sigma factors. Electrophoretic mobility shift assays showed that the DNA sequence corresponding to the untranslated leader of the psbAI message binds one or more proteins from an S. elongatus extract. The corresponding region of psbAII efficiently competed for this binding activity, suggesting a shared regulatory factor among these disparately regulated genes.

収録刊行物

• Journal of Bacteriology

  Journal of Bacteriology 183 (5), 1740-1747, 2001-03

  American Society for Microbiology

キーワード

• Molecular Biology
• Microbiology

詳細情報

• CRID: 1363388844345594112
• NII論文ID: 30021050170
• DOI: 10.1128/jb.183.5.1740-1747.2001
• ISSN: 10985530
• ISSN: 00219193
• Web Site: https://journals.asm.org/doi/pdf/10.1128/JB.183.5.1740-1747.2001
• データソース種別:
  • Crossref
  • CiNii Articles