The msf Gene Causes Environment-Specific Transcriptional Shifts Associated with Cell Surface Decorations and Metabolic Sensing in Haemophilus influenzae

ABSTRACT: Haemophilus influenzae is a diverse human-restricted bacterium that normally colonizes the healthy nasopharynx but also causes common infections. Comparisons of clinical isolate genomes previously identified an accessory gene msf that contained Sel1-like repeats and was associated with clinical disease. Mutant analysis had further found that msf improved survival in macrophages and increased systemic infection in an animal model. However, the role of msf in other conditions and its molecular function remain unknown. To identify protein-protein interactions with Msf, a yeast two-hybrid screen against an H. influenzae prey library was conducted, which found potential interactions with lipoprotein exporter protein LolD and an autotransporter adhesin Hap. To identify effects of msf on gene expression, we compared wild-type and mutant strains grown in multiple culture conditions by RNA-seq. The results indicate that msf modulates global gene expression in a condition-dependent manner, exerting an especially strong influence in starved surface-attached biofilm cells. The few consistent changes for mutants in exponential and stationary phases included decreased expression of two paralogous autotransporter adhesins. By contrast, mutant cells in starved surface-attached biofilms had dramatic changes in expression, including upregulation of protein translation and downregulation of alternative carbon metabolism. However, assays of 24-hour biofilm phenotypes found only subtle changes. Together, the results point to a speculative model of Msf functioning as an envelope-associated chaperone whose presence affects the relative expression of proteins at the outer membrane.

ORGANISM(S): Haemophilus influenzae

PROVIDER: GSE330915 | GEO | 2026/05/31

REPOSITORIES: GEO