Effect of nitric oxide on gene transcription - S-Nitrosylation of nuclear proteins

Chromatin structure defines if the DNA is accessible for the transcriptional machinery. In general, hyperacetylated chromatin (euchromatin) is often associated with high transcriptional activity since the transcriptional machinery has easy access to the DNA. In contrast, hypoacetylated chromatin (heterochromatin) has a very dense structure, which is usually transcriptionally inactive. Histone acetyl transferases are responsible for acetylation of lysine residues of histone N-tails, while histone deacetylases catalyze the hydrolysis of the ε-amino bond of N-ε-acetylated lysine residues of histones. In animals, members of both enzyme groups are known to be regulated by S-nitrosylation.

We are interested in NO-dependent regulation of histone acetylation in plants. We want to know, which chromatin regions (genes) are modulated by NO and which histone deacetylases are affected by NO.

Alexander Mengel, Alexandra Ageeva, Yongtao Han, Christian Lindermayr

NO mediated inhibition of HDACs might contribute to stress-gene induction. In non-challenged conditions HDAC-complexes repress transcription of stress-responsive genes by deacetylation of the corresponding chromatin regions. Upon exposure to stress, NO is produced resulting in the inhibition of HDAC-complexes. This might activate transcription in tight interplay with transcription factors. Blue cylinders: nucleosomes, green circles: acetyl groups, black arrow: transcriptional start site. (Mengel et al., 2017)