These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: A novel light- and heat-responsive regulation of the groE transcription in the absence of HrcA or CIRCE in cyanobacteria.
    Author: Kojima K, Nakamoto H.
    Journal: FEBS Lett; 2007 May 01; 581(9):1871-80. PubMed ID: 17434494.
    Abstract:
    The inactivation of the hrcA gene resulted in de-repression of the two CIRCE-containing groE genes in a cyanobacterium Synechocystis sp. strain PCC6803, indicating that the CIRCE operator/HrcA repressor system operates in the cyanobacterium. We found that the groE expression in the hrcA mutant is greatly induced by heat and/or light. Removal of a K-box containing and an N-box containing region upstream of the groESL1 promoter abolished light-induced transcription of a luxAB reporter gene fused with the groESL1 promoter. Similar sequences to the K-box, GTTCGG-NNAN-CCNNAC, were also found upstream of the dnaK2 genes. A specific binding of a protein(s) to the N-box, GATCTA, was detected by a gel mobility shift assay with using cell extracts. We propose that the cyanobacterial groEL expression is regulated by a putative positive mechanism mediated by these novel elements in addition to the HrcA/CIRCE system. The groEL2 genes from Synechococcus sp. strain PCC 7942 and Thermosynechococcus elongatus, which lack CIRCE, K-box, and N-box naturally, were also induced by heat and/or light, indicating that the control mechanism of the unique light-responsive groE expression is highly diversified in cyanobacteria.
    [Abstract] [Full Text] [Related] [New Search]