Regulation of multiple abiotic stress tolerance by LexA in the cyanobacterium Anabaena sp. strain PCC7120

Publication date: Available online 26 July 2018Source: Biochimica et Biophysica Acta (BBA) - Gene Regulatory MechanismsAuthor(s): Arvind Kumar, Anurag Kirti, Hema RajaramAbstractThe paradigm of involvement of LexA in regulation of only SOS-response in bacteria through the down-regulation of DNA repair genes was challenged in the unicellular cyanobacterium, Synechocystis PCC6803, wherein it was originally shown not to be associated with DNA repair and later also involved in management of carbon-starvation through up-regulation of C-metabolism genes. In the filamentous cyanobacterium, Anabaena sp. strain PCC7120, global stress management role for LexA and a consensus LexA-binding box (AnLexA-box) has been established using a LexA-overexpressing recombinant strain, AnlexA+. High levels of LexA rendered Anabaena cells sensitive to different DNA damage and oxidative stress-inducing agents, through the transcriptional down-regulation of the genes involved in DNA repair and alleviation of oxidative stress. LexA overexpression enhanced the ability of Anabaena to tolerate C-depletion, induced by inhibiting photosynthesis, by up-regulating genes involved in C-fixation and down-regulating those involved in C-breakdown, while maintaining the overall photosynthetic efficiency. A consensus LexA-binding box, AnLexA-box [AGT-N4–11-ACT] was identified upstream of both up- and down-regulated genes using a subset of Anabaena genes identified on the basis of proteomic analysis of AnlexA+ strai...
Source: Biochimica et Biophysica Acta (BBA) Gene Regulatory Mechanisms - Category: Genetics & Stem Cells Source Type: research