Growth Phase-Dependent Chromosome Condensation and Heat-Stable Nucleoid-Structuring Protein Redistribution in Escherichia coli under Osmotic Stress

• DOI: 10.1128/jb.00469-19
• Publication Date: 2019-09-04T13:59:26Z
• Authors: Nafiseh Rafiei; Martha Cordova; William Wiley Nav...; Joshua N. Milstein
• Keywords: Nucleoid; Premature chromosome condensation; DNA condensation

The heat-stable nucleoid-structuring (H-NS) protein is a global transcriptional regulator implicated in coordinating the expression of over 200 genes Escherichia coli, including many involved adaptation to osmotic stress. We have applied superresolved microscopy quantify intracellular and spatial reorganization H-NS response rapid shift. found that showed growth phase-dependent relocalization hyperosmotic shock. In stationary phase, detached from tightly compacted bacterial chromosome was excluded nucleoid volume an extended period time. This behavior absent during but induced by exposing osmotically stressed culture DNA gyrase inhibitor, coumermycin. chromosomal compaction/H-NS exclusion phenomenon occurred presence either potassium or sodium ions independent stress-responsive sigma factor σS paralog StpA.IMPORTANCE coordinates E. with large number both virulence drug resistance. report on novel observation dynamic compaction exposure high levels salt. stress results detachment proteins their subsequent expulsion periphery cells. this related mechanical properties chromosome, particular, how twisted coiled DNA. might act as biomechanical adapting bacteria salty environment.