Functional analysis of RPA complex in trypanosomatids and its involvement with telomeric DNA.

Author(s)

Raphael Souza Pavani

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2019-03-20

Examining board members

Maria Carolina Quartim Barbosa Elias Sabbaga; Carlos Renato Machado; Nadja Cristhina de Souza Pinto; Lucile Maria Floeter Winter

• Advisor: Maria Carolina Quartim Barbosa Elias Sabbaga; Maria Isabel Nogueira Cano

Abstract

Trypanosoma cruzi and Trypanosoma brucei are parasitic protozoa responsible for causing Chagas disease and sleeping sickness that result in a high number of deaths annually. These parasites present a complex life cycle that alternates between replicative and non-replicative lifeforms. Despite the characterization of a great number of molecular pathways, there are still many gaps in the understanding of the processes that coordinate the DNA metabolism of these organisms. Replication protein A (RPA), the major eukaryotic single-stranded binding protein, is a well-known heterotrimeric complex formed by three subunits RPA-1, RPA2, and RPA-3 that participates in various vital functions during replication, repair, and checkpoint signaling. RPA from trypanosomatids presents significant structural peculiarities compared to other eukaryotes such as the lacking of DBD-F (70N) domain that interacts with proteins majorly involved in DNA damage response (DDR) pathways and amino acids substitutions in conserved regions, raising questions regarding the conservation of canonical functions described in mammals and yeast. In this work, we show that RPA from trypanosomatids can interact with single-stranded DNA and is indeed important for replication and DNA damage response pathways. Moreover, we could find new features concerning trypanosomatids RPA such as the discovery of (i) non-described post-translation modifications (ii) a new RPA-like protein that seems to be exclusive of trypanosomatids interacting with RPA complex (iii) a nucleus-cytoplasm shuttle that is lifecycle dependent and (iv) high affinity for G-rich telomeric single stranded DNA. (AU)

• FAPESP's process: 14/02978-0 - Functional analysis of RPA complex in Trypanosoma cruzi and its involvement with telomeric DNA
• Grantee: Raphael Souza Pavani
• Support Opportunities: Scholarships in Brazil - Doctorate