Srivastava Akanksha, Kumar Arvind, Biswas Subhankar, Kumar Rajender, Srivastava Vaibhav, Rajaram Hema, Mishra Yogesh
Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
Plant Sci. 2023 Jan;326:111529. doi: 10.1016/j.plantsci.2022.111529. Epub 2022 Nov 1.
High radioresistance of the cyanobacterium, Anabaena sp. PCC7120 has been attributed to efficient DNA repair, protein recycling, and oxidative stress management. However, the regulatory network involved in these batteries of responses remains unexplored. In the present study, the role of a global regulator, LexA in modulating gamma (γ)-radiation stress response of Anabaena was investigated. Comparison of the cytosolic proteome profiles upon γ-radiation in recombinant Anabaena strains, AnpAM (vector-control) and AnlexA (LexA-overexpressing), revealed 41 differentially accumulated proteins, corresponding to 29 distinct proteins. LexA was found to be involved in the regulation of 27 of the corresponding genes based on the presence of AnLexA-Box, EMSA, and/or qRT-PCR studies. The majority of the regulated genes were found to be involved in C-assimilation either through photosynthesis or C-catabolism and oxidative stress alleviation. Photosynthesis, measured in terms of PSII photophysiological parameters and thylakoid membrane proteome was found to be affected by γ-radiation in both AnpAM and AnlexA cells, with LexA affecting them even under control growth conditions. Thus, LexA functioned as one of the transcriptional regulators involved in modulating γ-radiation stress response in Anabaena. This study could pave the way for a deeper understanding of the regulation of γ-radiation-responsive genes in cyanobacteria at large.
蓝藻鱼腥藻7120具有高度的辐射抗性，这归因于其高效的DNA修复、蛋白质循环利用和氧化应激管理。然而，参与这些反应的调控网络仍未被探索。在本研究中，研究了全局调控因子LexA在调节鱼腥藻对γ辐射应激反应中的作用。对重组鱼腥藻菌株AnpAM（载体对照）和AnlexA（LexA过表达）在γ辐射后的胞质蛋白质组图谱进行比较，发现了41种差异积累的蛋白质，对应于29种不同的蛋白质。基于AnLexA-Box的存在、电泳迁移率变动分析（EMSA）和/或实时定量PCR（qRT-PCR）研究，发现LexA参与了27个相应基因的调控。发现大多数受调控的基因通过光合作用或碳分解代谢参与碳同化和氧化应激缓解。以PSII光生理参数和类囊体膜蛋白质组来衡量的光合作用，在AnpAM和AnlexA细胞中均发现受到γ辐射的影响，甚至在对照生长条件下LexA也会对其产生影响。因此，LexA作为参与调节鱼腥藻γ辐射应激反应的转录调控因子之一发挥作用。这项研究可能为更深入了解蓝藻中γ辐射响应基因的调控铺平道路。
