Gene Expression Strategies of the Pathogenic Neisseria
J.R. Mellin and Stuart Hill
from: Neisseria: Molecular Mechanisms of Pathogenesis (Edited by: Caroline Genco and Lee Wetzler). Caister Academic Press, U.K. (2010)
The pathogenic Neisseria consists of the species Neisseria gonorrhoeae and Neisseria meningitidis, both of which are Gram-negative diplococci and exclusive human pathogens. Neisseria gonorrhoeae is the causative agent of gonorrhoeae and is transmitted via sexual contact and principally infects the mucosal surfaces of the cervix in women and the urethra in men. In contrast, N. meningitidis is transmitted via respiratory droplets leading to colonization of the nasopharynx, and in rare cases, dissemination of meningococci into the bloodstream and cerebrospinal fluid leading to meningitis and/or septicemia. In order to effectively colonize their respective niches within the human host, both N. gonorrhoeae and N. meningitidis must successfully compete with significant resident flora for space and nutrients, as well as evade host immune defenses. Consequently, this requires an ability to quickly sense and respond to a plethora of changing environmental stimuli. At the most fundamental level, this requires the modulation of gene expression as circumstances require. The following is a discussion of mechanisms of bacterial gene regulation with a specific focus on the strategies utilized by the pathogenic Neisseria to control gene expression of factors with roles in Neisserial pathogenesis. Topics will include the use of alternative sigma factors, positive and negative regulation of gene transcription by specific transcription factors and adaptation via the accumulation of temporally random spontaneous mutations within chromosomal DNA. Additionally, some discussion will focus on emerging mechanisms of gene regulation such as posttranscriptional regulation via small RNA molecules read more ...