William Lenh
Rosbash Laboratory
Department of Biology
Brandeis University
Unravelling the Molecular Basis of Temperature Compensation Using the Kinase Doubletime
Poster Abstract
The circadian clock controls the organism’s behavior and physiology throughout the day. These physiological features are still rhythmic in the absence of any external cues, such as temperature or light. More interestingly, these rhythms do not only persist in total darkness, but they have the same speed at twenty and thirty centigrade, meaning that the clock is temperature compensated. The molecular basis for temperature compensation is yet to be found, as well as the underlying neuronal mechanisms for this level of control. Previous studies suggested that the kinase Doubletime (DBT) may play a role in this process. Also DBT has been shown to play a major role in the circadian feedback loop. It phosphorylates Period (PER) and allows it to enter the nucleus and associate with Timeless (TIM) to inhibit the transcription of PER and TIM. In order to investigate this, we re-established an in vivo Timeless (TIM) -transcription assay in Drosophila melanogaster. By using the fusion of the TIM-promoter to the coding sequence of the luciferase gene, we were able to monitor the TIM mRNA levels over several days and observed prominent cycling of the transcript at different temperatures. It appears that DBT is necessary for temperature compensation in TIM transcription: Expressing a dominant-negative isoform of DBT shows significantly higher TIM-luciferase levels at 28 degrees compared to 18 degrees. We also analyzed the locomotor activity and rhythmicity of flies with altered DBT expression and found interesting differences.
Personal Statement
My time with the Rosbash lab for the past few years have been very enjoyable and left a very deep impression on me. I honestly doubt that I will ever have this type of lab experience again. I conducted experiments that applied my knowledge of biology gained through courses at Brandeis University such as DNA cloning and creating recombinant fly lines. Likewise, I created flies that have fluorescent red eyes, dissected fly brains, and delved into the molecular mechanisms behind the circadian rhythm. Aside from this, working in the Rosbash lab has furthered my knowledge of science that is not taught in courses offered at Brandeis. I developed problem solving skills that are completely different from that of the course work. I learned how to think from a scientific standpoint, questioning everything and trying to understand everything to the fullest as opposed to rigorous memorization of series of algorithmic steps to solve a problem. This experience also reminded me of the value of working diligently that my parents have instilled upon me. Because of the M.R. Bauer Foundation, I am able to continue this wonderful journey in the Rosbash lab.