Inhibition of AtMYB2 DNA-binding by nitric oxide involves cysteine S-nitrosylation

• Published in: Biochemical and biophysical research communications 2007-10, Vol.361 (4), p.1048-1053
• Main Authors: Serpa, Viviane, Vernal, Javier, Lamattina, Lorenzo, Grotewold, Erich, Cassia, Raul, Terenzi, Hernán
• Format: Article
• Language: English
• Subjects: Arabidopsis; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; AtMYB2; Biotin switch; Cysteine - chemistry; DNA - metabolism; DNA-Binding Proteins - chemistry; EMSA; Nitric oxide; Nitric Oxide - chemistry; Nitric Oxide Donors - pharmacology; Nitroprusside - pharmacology; Nitrosylation; Oxidation-Reduction; Protein Processing, Post-Translational; R2R3-MYB; S-Nitrosoglutathione - pharmacology; Trans-Activators - chemistry; Trans-Activators - metabolism
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2007.07.133

Nitric oxide (NO) can influence the transcriptional activity of a wide set of Arabidopsis genes. The aim of the present work was to investigate if NO modifies DNA-binding activity of AtMYB2 (a typical R2R3-MYB from Arabidopsis thaliana), by a posttranslational modification of its conserved Cys53 residue. We cloned a fully active minimal DNA-binding domain of AtMYB2 spanning residues 19–125, hereafter called M2D. In EMSA assays, M2D binds the core binding site 5′-[A]AACC[A]-3′. The NO donors SNP and GSNO inhibit M2D DNA-binding. As expected for a Cys S-nitrosylation, the NO-mediated inhibitory effect was reversed by DTT, and S-nitrosylation of Cys53 in M2D was detected by biotin switch assays. These results demonstrate that the DNA-binding of M2D is inhibited by S-nitrosylation of Cys53 as a consequence of NO action, thus establishing for the first time a relationship between the redox state and DNA-binding in a plant MYB transcription factor.