Phase-variable Type I methyltransferase M.NgoAV from Neisseria gonorrhoeae FA1090 regulates phasevarion expression and gonococcal phenotype

Monika Adamczyk-Poplawska; Pawel Bacal; Agnieszka Mrozek; Natalia Matczynska; Andrzej Piekarowicz; Agnieszka Kwiatek

doi:10.3389/fmicb.2022.917639

Phase-variable Type I methyltransferase M.NgoAV from Neisseria gonorrhoeae FA1090 regulates phasevarion expression and gonococcal phenotype

Front Microbiol. 2022 Oct 4:13:917639. doi: 10.3389/fmicb.2022.917639. eCollection 2022.

Authors

Monika Adamczyk-Poplawska¹, Pawel Bacal², Agnieszka Mrozek¹, Natalia Matczynska¹, Andrzej Piekarowicz¹, Agnieszka Kwiatek¹

Affiliations

¹ Department of Molecular Virology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland.
² Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland.

Abstract

The restriction-modification (RM) systems are compared to a primitive, innate, prokaryotic immune system, controlling the invasion by foreign DNA, composed of methyltransferase (MTase) and restriction endonuclease. The biological significance of RM systems extends beyond their defensive function, but the data on the regulatory role of Type I MTases are limited. We have previously characterized molecularly a non-canonical Type I RM system, NgoAV, with phase-variable specificity, encoded by Neisseria gonorrhoeae FA1090. In the current work, we have investigated the impact of methyltransferase NgoAV (M.NgoAV) activity on gonococcal phenotype and on epigenetic control of gene expression. For this purpose, we have constructed and studied genetic variants (concerning activity and specificity) within M.NgoAV locus. Deletion of M.NgoAV or switch of its specificity had an impact on phenotype of N. gonorrhoeae. Biofilm formation and planktonic growth, the resistance to antibiotics, which target bacterial peptidoglycan or other antimicrobials, and invasion of human epithelial host cells were affected. The expression of genes was deregulated in gonococcal cells with knockout M.NgoAV gene and the variant with new specificity. For the first time, the existence of a phasevarion (phase-variable regulon), directed by phase-variable Type I MTase, is demonstrated.

Keywords: DNA methylation; Neisseria gonorrhoeae; NgoAV; Type I MTase; pathogenicity; phasevarion; restriction-modification.