Functional characterization of two WD40 family proteins, Alr0671 and All2352, from Anabaena PCC 7120 and deciphering their role in abiotic stress management

• Published in: Plant molecular biology Vol. 110; no. 6; pp. 545 - 563
• Main Authors: Rai, Krishna Kumar, Singh, Shilpi, Rai, Ruchi, Rai, L. C.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2022; Springer; Springer Nature B.V
• Subjects: Abiotic stress; Amino acids; Anabaena; Biochemistry; Biomedical and Life Sciences; Cellular proteins; Chromatin; Cyanobacteria; DNA binding proteins; Drought; Electrophoretic mobility; Ethylenediaminetetraacetic acid; Gene expression; Immunoprecipitation; Kinases; Life Sciences; Oxidative stress; Phosphorylation; Plant Pathology; Plant Sciences; Promoters (Genetics); Protein binding; Protein families; Proteins; Reactive oxygen species; Recombinant proteins; Transcription factors; WD40 proteins; Abiotic stress tolerance; ChIP; Promoter analysis; EMSA
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-022-01306-4

WD40 domain-containing proteins are one of the eukaryotes’ most ancient and ubiquitous protein families. Little is known about the presence and function of these proteins in cyanobacteria in general and Anabaena in particular. In silico analysis confirmed the presence of WD40 repeats. Gene expression analysis indicated that the transcript levels of both the target proteins were up-regulated up to 4 fold in Cd and drought and 2–3 fold in heat, salt, and UV-B stress. Using a fluorescent oxidative stress indicator, we showed that the recombinant proteins were scavenging reactive oxygen species (ROS) (4–5 fold) more efficiently than empty vectors. Chromatin immunoprecipitation analysis (ChIP) and electrophoretic mobility shift assay (EMSA) revealed that the target proteins function as transcription factors after binding to the promoter sequences. The presence of kinase activity (2–4 fold) in the selected proteins indicated that these proteins could modulate the functions of other cellular proteins under stress conditions by inducing phosphorylation of specific amino acids. The chosen proteins also demonstrated interaction with Zn, Cd, and Cu (1.4–2.5 fold), which might stabilize the proteins’ structure and biophysical functions under multiple abiotic stresses. The functionally characterized Alr0671 and All2352 proteins act as transcription factors and offer tolerance to agriculturally relevant abiotic stresses. Key message Alr0671 and All2352 are novel WD40 proteins of Anabaena capable of regulating biochemical functions and abiotic stress tolerance by acting as a transcription factor and mediating DNA-protein interaction.