Lysine Methylation Modulates the Interaction of Archaeal Chromatin Protein Cren7 With DNA

Abstract

Cren7 and Sis7d, two chromatin proteins from Sulfolobus islandicus, undergo extensive methylations at multiple lysine residues to various extents. Whether this highly conserved protein serves an epigenetic role in the regulation of the structure and function of the chromosome remains unclear. In the present study, we show that methylation significantly affects Cren7, but not Sis7d, in the ability to bind DNA and to constrain negative DNA supercoils. Strikingly, methylated Cren7 was significantly less efficient in forming oligomers or mediating intermolecular DNA bridging. Single-site substitution mutation with glutamine reveals that methylation of the four lysine residues (K24, K31, K42, and K48) of Cren7 at the protein-DNA interface, which are variably conserved among Cren7 homologues from different branches of the Crenarchaeota, influenced Cren7-DNA interactions in different manners. We suggest that dynamic methylation of Cren7 may represent a potential epigenetic mechanism involved in the chromosomal regulation in crenarchaea.

To be or not to be an anti-CRISPR: AcrIII-1 and the importance of working with native biological systems

“…Interestingly, a knockout mutant of the lysine methyltransferase shows differential expression of genes involved in metabolism and genes without functional annotation, plus several genes located in the variable region of the S. islandicus strain probably corresponding to integrated viruses (Chu et al 2016) (Figure S9), supporting a role of protein methylation in stress response. Additionally, differential methylation in response to heat-shock of Cren7, a SiL_1451 substrate, affects the DNA-binding ability of Cren7 potentially impacting chromosomal regulation, suggesting a role of SiL_1451 in mediating epigenetic regulation in response to environmental stress (Ding et al 2022). The mechanism by which inhibition of SiL_1451 methyltransferase activity aids SIRV2 replication remains to be elucidated.…”

“…S9), supporting a role of protein methylation in stress response. Additionally, differential methylation in response to heat-shock of Cren7, a SiL_1451 substrate, affects the DNA-binding ability of Cren7 potentially impacting chromosomal regulation, suggesting a role of SiL_1451 in mediating epigenetic regulation in response to environmental stress 52 . The mechanism by which inhibition of SiL_1451 methyltransferase activity aids SIRV2 replication remains to be elucidated.…”

An archaeal chromatin protein condenses DNA through bridging-induced phase separation

“…Gels were stained with EB, and imaged using a gel imager (BIORAD GELDOC2000). Biolayer interferometry (BLI) assays BLI assays were carried out as described previously 21 with modi cations. The assays were performed at room temperature using the Octet Red96 system (ForteBio, USA).…”