NSF Award
2326038
Reverse transcription converts RNA into DNA, in contrast to the typical flow of genetic information from DNA to RNA. Enzymes capable of DNA polymerization on RNA templates are called reverse transcriptases (RTs). RTs are believed to have played a major role in the transition from the primordial RNA world to the modern DNA-based forms of life. Since then, however, RT activity has mostly been employed by various selfish mobile genetic elements, such as retrotransposons or retroviruses. Beneficial uses of RT in cells are exceptionally rare, with eukaryotic telomerases being the only known example. The discovery by the researcher of single-copy reverse transcriptase-related genes with an intact active center, representing the only type of RTs present in both bacteria and eukaryotes, provides a unique opportunity to investigate the evolution of beneficial RT functions across different domains of Life. The function of these genes and their products will be studied by molecular, genetic, biochemical, and physiological methods, focusing on their response to environmental perturbations. Furthermore, the project involves extensive training for summer undergraduates by engaging them in individual research projects, providing the much-needed research experience as they prepare for graduate school applications and/or explore other career paths.<br/><br/>To gain insights into the process of recruitment of an RNA-dependent polymerase into the metabolic environment of prokaryotic and eukaryotic cells, genetic screens aimed at dissecting regulatory pathways in model filamentous fungi will be combined with biochemical and functional assays in response to specific stress conditions, which will also be performed in native and heterologous systems such as rotifers and bacteria. The proposed research would uncover the nature of the evolutionary adaptation of RNA-dependent DNA synthesis for purposes entirely different from those previously examined, with the emergence of beneficial functions provided by additional domains endowing the host species with extra layers of flexibility in response to environmental stresses. Functional comparisons with the telomerase system should help to define the prerequisites for RT domestication. Finally, comparative analysis of different RT types would represent an essential step towards closure of the remaining gaps in the overall picture of RT structure, function, and evolution.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
