CPT1 and PyK Gene Expression Changes with Different Physiological Conditions between 2 Resistant to Starvation Fly Lines: A Basic Science Experiment

Abstract

Background: Many organisms adapt to different physiological conditions by changing their gene expression to increase their chances of survival. Drosophila melanogaster fly line 765 show low resistance to starvation and line 362 show high resistance to starvation and were selected to examine how their gene expression would change based on a starved and refed environment. The genes selected were both metabolic genes CPT1 and PyK. CPT1 is responsible for fat breaking and PyK is responsible for the catalysis of the final stage in glycolysis. Methods: Specific Drosophila melanogaster fly lines were selected that showed either a high or low resistance to starvation. These lines were selected to examine how their gene expression would change based on a starved and re-fed environment. RNA was isolated from both sets of flies so that reverse transcriptase reactions could be performed using RT-PCR to generate complementary DNA using reverse transcriptase. The complementary DNA served as a template for amplification using endpoint and quantitative PCR to determine if gene expression would change between the two fly lines. A survival curve was also generated to illustrate the graphical differences among the various fly lines. Results: Quantitative PCR and gene expression data concluded that there was a difference between gene expression of CPT1 and PyK between the two lines. CPT1 quantitative PCR data did not match gene expression predictions, whereas, PyK did in both line 765 and 362. Conclusions: The finding that CPT1 was able to generate Ct values but was unable to adhere to the expected predictions of gene expression is indicative of line 765 having a problem sensing the nutrients and unlikely to be a problem in transcription. Future directions include to characterize both glycogen and triglyceride levels at time t=0 hrs, starved, and re-fed conditions and to investigate if there is a connection between enzyme efficiency and condition type between the two lines.