A Heterologous Screen of the Neisseria gonorrhoeae Genetic Library and its Effects on the Expression of the Gene of Unknown Function, NG1684

Abstract

Neisseria gonorrhoeae, is a gram negative diplococcus, and is the causative agent for the sexually transmitted disease gonorrhea. Developments of a vaccine for gonococcal infection have also been unsuccessful because no cross-protective immunity can be attained. N. gonorrhoeae targets and attacks mucosal tissue via virulence factors: Type IV Pilus, Opacity-associated proteins (Opa), porA and porB porin channels, as well as high antigenic variation. The purpose of this study was to discover regulators within the Neisseria genome that could affect the expression of NG1684, thereby responding to adherence and facilitating invasion of host cells. Information about new regulators may be of clinical significance as it could lead to novel treatments for gonorrhea, as an alternative to the current use of antibiotics. By completing this heterologous screen we have found many genetic implications affecting NG1684 gene expression, the most up-regulated gene when gonococci adhere to human epithelial cells. It is possible that these genes encode products involved in pathogenesis. One known implication comes from the insert in sample pBW03, which encodes for the NnRs like proteins. Another implication could possibly arise from the plasmid insert of transformant pBW01 as it encodes for genes of the N. gonorrhoeae strain MS11 pathogenicity island. This island, separate from the sequence homology we discovered on the pBW01 plasmid insert, encodes for a Type IV secretion system, which in other pathogens serves a large role in pathogenesis.