Using Synthetic Biology to Investigate the Impact of Temperature On Gene Expression

Abstract

Temperature is known to impact many important processes including the efficiency of the immune system. The objective of this work was to use synthetic biology to evaluate how temperature impacts gene expression. To do this we used recombinant DNA technology to generate two bioreporter constructs in E. coli, one that encoded a temperature sensitive promoter controlling the gene for red fluorescent protein (RFP), and another encoding a constitutive promoter controlling RFP. RFP is a protein found in sea anemones which fluoresces red following exposure to red light and causes a red pigmentation in bacterial cells. We hypothesized the construct containing the temperature sensitive promoter would vary in RFP production while the construct with the constitutive promoter would produce constant levels of RFP. To test each construct, we incubated replicate samples at four different temperatures: 20, 30, 37, and 42?C in broth and agar media. RFP expression was then evaluated at each temperature by visually scoring the pigment intensity of cells on agar media and by using a fluorometer to measure fluorescent intensity. Surprisingly, both of our constructs varied in RFP production in the temperatures tested. This suggest that either RFP or the constitutive promoter are also temperature responsive.