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Doctoral Thesis
DOI
https://doi.org/10.11606/T.42.2019.tde-14032023-173149
Document
Author
Full name
Raphael Souza Pavani
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2019
Supervisor
Committee
Sabbaga, Maria Carolina Quartim Barbosa Elias (President)
Machado, Carlos Renato
Pinto, Nadja Cristhina de Souza
Winter, Lucile Maria Floeter
Title in Portuguese
Análise funcional do complexo Replication Protein A em tripanossomatídeos e seu envolvimento com DNA telomérico.
Keywords in Portuguese
Replicação
Trypanosoma
Danos de DNA
RPA
Telômeros
Abstract in Portuguese
Trypanosoma cruzi e Trypanosoma brucei são protozoários parasitos responsáveis pela doença de Chagas e pela doença do sono, as quais resultam em um elevado número de mortes anualmente. Esses parasitos possuem um ciclo de vida complexo que alterna entre formas de vida replicativas e não replicativas. Apesar da caracterização de um grande número de vias moleculares nestes organismos, ainda existem muitas lacunas na compreensão dos processos que coordenam o metabolismo do DNA. A proteína Replication Protein A (RPA), principal ligante de fita simples de DNA de eucariotos, é um complexo heterotrimérico formado por três subunidades RPA-1, RPA2 e RPA-3 que participa em vários processos fundamentais como replicação, reparo e sinalização de checkpoint. A RPA de tripanossomatídeos apresenta peculiaridades estruturais significativas em comparação a outros eucariotos, como a falta de domínio de DBD-F (70N) que interage com proteínas majoritariamente envolvidas na resposta a danos no DNA (DDR) e substituições em resíduos de aminoácidos em regiões conservadas, levantando questões sobre a conservação de funções canônicas descritas em mamíferos e leveduras. Neste trabalho, mostramos que o RPA de tripanossomatídeos pode interagir com DNA fita simples e é de fato importante para replicação e resposta a danos de DNA. Além disso, conseguimos encontrar diversas novas características nas RPA de tripanossomatídeos, como a descoberta de (i) modificações pós-traducionais não descritas (ii) uma nova proteína RPA-like que parece ser exclusiva de tripanossomatídeos interagindo com o complexo RPA (iii) um processo de exportação nuclear ciclo de vida dependente e (iv) alta afinidade pelo DNA de fita simples telomérico rico em G.
Title in English
Functional analysis of RPA complex in trypanosomatids and its involvement with telomeric DNA.
Keywords in English
Replication
Trypanosoma
DNA damage
RPA
Telomeres
Abstract in English
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.
 
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Release Date
2025-03-13
Publishing Date
2023-03-15
 
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