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

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.