Biology subjects

Galle, M.

Publications and source records attributed to Galle, M..

2 recordsLinked to original sources

bioRxiv2025

DNA-binding and dimerization of the SOG1 NAC domain are functionally linked with its ability to undergo liquid-liquid phase separation

Liquid-liquid phase separation is a key phenomenon in the regulation of transcription in eukaryotes leading to the formation of so-called membraneless organelles. While transcription factors take part in several types of membrane-less organelles, it remains unclear how specific DNA binding, multivalent interactions with DNA/RNA and condensation are interlinked. Here we show that the NAC domain of SOG1 (SOG1NAC), a transcription factor that is central to the DNA damage response in plants, can undergo liquid-liquid phase separation in vitro in the presence of both RNA or double stranded DNA. This behaviour, as well as the ability of SOG1NAC to bind DNA in a sequence-specific manner are dependent on its potential to form homodimers and the presence of a cluster of positive charges in its DNA binding site. Short double-stranded DNA fragments containing the sequence motif that is specifically recognized by SOG1NAC inhibit RNA-mediated phase separation, suggesting overlapping binding sites for DNA and RNA. This may reflect a complex interplay between DNA and RNA binding that could control the formation of condensates at transcription sites.

biochemistry↗

bioRxiv2020

Arabidopsis Casein Kinase 2 triggers Stem Cell Exhaustion under Al Toxicity and Phosphate Deficiency Through activation of the DNA Damage Response pathway

Aluminum (Al) toxicity and inorganic phosphate (Pi) limitation are widespread chronic abiotic and mutually enhancing stresses that profoundly affect crop yield. Both stresses cause a strong inhibition of root growth, resulting from a progressive exhaustion of the stem cell niche. Here, we report on a casein kinase 2 (CK2) inhibitor identified by its capability to maintain a functional root stem cell niche under Al toxic conditions. CK2 operates through phosphorylation of the cell cycle checkpoint activator SUPPRESSOR OF GAMMA RADIATION1 (SOG1), priming its activity under DNA-damaging conditions. In addition to yielding Al tolerance, CK2 and SOG1 inactivation prevents meristem exhaustion under Pi starvation, revealing the existence of a low Pi-induced cell cycle checkpoint that depends on the DNA damage activator ATAXIA-TELANGIECTASIA MUTATED. Overall, our data reveal an important physiological role for the plant DNA damage response pathway under agriculturally limiting growth conditions, opening new avenues to cope with Pi limitation. ONE-SENTENCE SUMMARYCasein kinase 2 and DNA damage response regulators play a pivotal role in the control of Arabidopsis root growth in response to Al toxicity and phosphate limitation.

plant biology↗