Biological Sciences, School of


First Advisor

Hideaki Moriyama

Date of this Version


Document Type



Riera-Ruiz, C. (2021). Studies of the dUTPase of the Western Corn Rootworm. Dissertations and Theses in Biological Sciences. University of Nebraska-Lincoln


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In partial Fulfillment of Requirements For the Degree of Master of Science, Major: Biological Sciences, Under the Supervision of Professor Hideaki Moriyama. Lincoln, Nebraska: May 2021

Copyright © 2021 Carlos A. Riera-Ruiz


The western corn rootworm (WCR), Diabrotica virgifera virgifera, is a major corn pest in the United States and Europe. WCR has developed resistance to multiple management strategies, including Cry proteins. Even though the biology and ecology have been thoroughly studied in WCR, their genome and molecular mechanisms are understudied. This work focuses on the ubiquitous enzyme deoxyuridine triphosphatase (dUTPase) encoded by the DUT gene. dUTPase hydrolyzes dUTP into dUMP and pyrophosphate. It contributes to genome stability by keeping the uracil-to-thymine ratio at a certain level. In WCR, two dUTPase isoforms were predicted using transcriptome analyses. These two potential isoforms shared the core part of the enzyme including five conserved motifs forming active sites while they differed in the amino-termini. To assess the enzymatic activity and substrate specificity, the core sequence of the WCR dUTPase gene was cloned, expressed in Escherichia coli, and purified. The WCR dUTPase hydrolyzed dUTP but not dATP, dTTP, dCTP or dGTP. Structural analysis showed that Lys92 on WCR dUTPase seemed to govern the substrate specificity. This study revealed the properties of key pyrimidine metabolism partly of WCR and provided the basis for future studies.

Advisor: Hideaki Moriyama