Investigating the Regulatory roles of Archaeal Initiation Factors
Category: Research Poster
Author(s): Liam Gosnell
Presenter(s): Liam Gosnell
Mentors(s): Jason McDonald, Thomas Santangelo
Regulation of gene expression is central to cellular survival and enables adaptation to a given environment. Transcription serves as a primary regulatory checkpoint, where RNA polymerase (RNAP) and basal transcription factors facilitate promoter recognition and transcription initiation. Eukaryotic transcription initiation requires the coordinated action of numerous general transcription factors, creating a complex regulatory environment. Archaea and Eukarya retain homologous promoter elements that are recognized by the conserved initiation factors TBP and TFB/TFIIB. Because Archaeal transcription utilizes a component simplified and homologous system to the eukaryotic RNAP II initiation machinery, Archaea serve as an effective model system to investigate the core mechanisms of transcription initiation and promoter-dependent transcriptional regulation. Thermococcus kodakarensis (Tko) is a hyperthermophilic anaerobic archaeon that is genetically tractable with established techniques to characterize transcriptional processes. Tko, like many other archaea, encodes multiple paralogs of TFB: TFB1 and TFB2. Given Archaea possess constrained genomes that minimize redundancy, the retention of multiple TFB paralogs indicates a functional differentiation between paralogs that confers fitness advantages through transcriptional flexibility. Deletion of either TFB paralog in Tko produces modest transcriptomic changes, and evidence in halophilic Archaea suggests that alternative paralogs display distinct promoter preferences through BRE-dependent specialization. In this study we use relatively quantitative western blotting to characterize the abundances of TFB1 and TFB2 across variable growth conditions. Archaea may represent a model for primordial transcription systems, and insights into the retention and diversification of TFB paralogs in archaeal extremophiles may illuminate the selective pressures that shape transcriptional regulatory complexity.