This project aims to employ a broad variety of proteomic, genetic, and bioinformatic techniques for use in studies that will further characterize those genes, and their corresponding functions, necessary for adaptation to variable salinities in the model haloarchaeon, Haloferax volcanii. Proteomic analyses have led to the discovery of a set of salinity-regulated proteins in Hfx. volcanii that now await detailed characterization of the mechanisms involved in their regulation. Among the proteins identified were a bacterial-like transcriptional activator that is regulated by NaCl concentrations at the level of transcription. The gene encoding this protein is a homolog of the bacterial pspA gene that is regulated in response to environmental stress. Given its integral role in sensing a variety of membrane stressors, it is hypothesized that pspA may play an important role in hypo- and/or hypersaline adaptation in Hfx. volcanii. Planned research will address the following questions: 1) do genes encoding salinity-regulated proteins share a common mechanisms of regulation?; 2) does Hfx. volcanii PspA function as a transcriptional activator and in a manner akin to that seen in bacteria?; 3) does Hfx. volcanii induce similar types of genes/proteins in response to low-salt stress as those seen under high-salt inducing conditions? The information obtained in this research will shed critical insight into how Hfx. volcanii is able to sustain growth and remain viable over a wide range of salinities in its natural environment. Furthermore, by providing the first experimental evidence for stress-regulated PspA activity in Archaea, its functional relationship to homologs present in bacterial and eukaryotic domains of life can be elucidated. The broader impacts of this study will chiefly involve the participation and training of a number of undergraduate research students, as this research takes place at Rider University, a small, liberal arts school with no graduate programs in the sciences.
