English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

H-NS is a majorEscherichia coli nucleoid-associated protein involved in bacterial DNA condensation and global modulation of gene expression. This protein exists in cells as at least two different isoforms separable by isoelectric focusing. Among other phenotypes, mutations inhns result in constitutive expression of theproU andfimB genes, increasedfimA promoter inversion rates, and repression of theflhCD master operon required for flagellum biosynthesis. To understand the relationship between H-NS structure and function, we transformed a clonedhns gene into a mutator strain and collected a series of mutant alleles that failed to repressproU expression. Each of these isolatedhns mutant alleles also failed to repressfimB expression, suggesting that H-NS-specific repression ofproU andfimB occurs by similar mechanisms. Conversely, alleles encoding single amino acid substitutions in the C-terminal DNA-binding domain of H-NS resulted in significantly reduced affinity for DNA yet conferred a wild-typefimA promoter inversion frequency, indicating that the mechanism of H-NS activity in modulating promoter inversion is independent of DNA binding. Furthermore, two specific H-NS amino acid substitutions resulted in hypermotile bacteria, while C-terminal H-NS truncations exhibited reduced motility. We also analyzed H-NS isoform composition expressed by varioushns mutations and found that the N-terminal 67 amino acids were sufficient to support posttranslational modification and that substitutions at positions 18 and 26 resulted in the expression of a single H-NS isoform. These results are discussed in terms of H-NS domain organization and implications for biological activity.

journal of bacteriology

Phenotypic Analysis of Random <i>hns</i> Mutations Differentiate DNA-Binding Activity from Properties of <i>fimA</i> Promoter Inversion Modulation and Bacterial Motility

Phenotypic Analysis of Random hns Mutations Differentiate DNA-Binding Activity from Properties of fimA Promoter Inversion Modulation and Bacterial Motility