I propose to study the factors that govern chlamydial persistence. To achieve this, I will take advantage of newly developed genetic approaches that may serve to identify the genes conferring C. trachomatis the ability to persist in response to a stress factors that this bacteria can encounter in vivo during infection and then resume normal replication upon removal of the stressing condition. Additionally, I will use a new adaptation that I developed during my post-doctoral training for label-free quantitative proteomics [40], particularly liquid chromatography tandem mass spectrometry (LC/LC-MS/MSE), to extensively characterize the proteome of C. trachomatis during persistence and reactivation. This will allow for identification of proteins differentially expressed (and thereby potentially important) during those states. Finally, I will evaluate the role of persistence in vivo using rodent infection models.