Charged residues in the H-NS linker drive DNA binding and gene silencing in single cells

Yunfeng Gao, Yong Hwee Foo, Ricksen S. Winardhi, Qingnan Tang, Jie Yan, Linda J. Kenney

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Nucleoid-associated proteins (NAPs) facilitate chromosome organization in bacteria, but the precise mechanism remains elusive. H-NS is a NAP that also plays a major role in silencing pathogen genes. We used genetics, single-particle tracking in live cells, superresolution microscopy, atomic force microscopy, and molecular dynamics simulations to examine H-NS/DNA interactions in single cells. We discovered a role for the unstructured linker region connecting the N-terminal oligomerization and C-terminal DNA binding domains. In the present work we demonstrate that linker amino acids promote engagement with DNA. In the absence of linker contacts, H-NS binding is significantly reduced, although no change in chromosome compaction is observed. H-NS is not localized to two distinct foci; rather, it is scattered all around the nucleoid. The linker makes DNA contacts that are required for gene silencing, while chromosome compaction does not appear to be an important H-NS function.

Original languageEnglish (US)
Pages (from-to)12560-12565
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number47
DOIs
StatePublished - Nov 21 2017
Externally publishedYes

Keywords

  • Atomic force microscopy
  • H-NS
  • Nucleoid-associated proteins
  • Single-particle tracking
  • Superresolution microscopy

ASJC Scopus subject areas

  • General

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