Transcription Factor FKH-9 Regulates Oxidative Stress Responses in Caenorhabditis Elegans

The biological process of energy production is an essential mechanism needed for the strength and survival of many living organisms. Although highly beneficial, energy production can also exert a negative effect through the creation of reactive oxygen species (ROS). ROS are highly reactive chemicals that are generated when oxygen molecules get reduced in the cell such as from mitochondrial oxidative metabolism. This production of ROS is a normal cellular event; however, its accumulation can cause oxidative stress by modifying compounds, interfering with signalling cascades, and damaging macromolecules. Therefore, the cell is known to have many detoxification systems that involve specific cellular signalling pathways. One pathway seen in C. elegans is the skinhead-1 (SKN-1) glutathione s-transferase-4 (GST-4) pathway. GST-4 is an important detoxification enzyme that helps reduce the accumulation of ROS in the cell, while the SKN-1 transcription factor regulates gst-4 at the promoter. However, under non-oxidative stress-inducing conditions SKN-1 is hypothesized to be indirectly held in the cytoplasm by the BRCA1 associated protein-2 (BRAP-2). Recently, our lab discovered elevated gst-4 levels in brap-2(ok1492) deletion mutants, however RNAi of the transcription factor forkhead-9 (fkh-9) in these mutants caused a decrease in gst-4 expression. I have confirmed that FKH-9 is needed for gst-4 expression levels in brap-2(ok1492) mutated worms. I have also uncovered its potential role in the signalling pathway as FKH-9 significantly increased SKN-1-mediated activity at the skn-1c promoter indicating a potential synergistic effect with SKN-1 to help increase SKN-1 transcription levels. Biological analysis of FKH-9 was also carried out and mutants were seen to have compromised longevity and survival under various stress-inducing conditions compared to wild-type (WT). Thus, my investigation ultimately presents an initial indication upon the role and function of FKH-9 in the C. elegans oxidative stress response.