Recruitment kinetics of the homologous recombination pathway in procyclic forms of Trypanosoma brucei after ionizing radiation treatment

Author(s)

Marin, Paula Andrea ^[1] ; da Silva, Marcelo Santos ^[1] ; Pavani, Raphael Souza ^[1] ; Machado, Carlos Renato ^[2] ; Elias, Maria Carolina ^[1]

Affiliation

^[1] Butantan Inst, Ctr Toxins Immune Response & Cell Signaling CeTIC, Cell Cycle Lab LECC, BR-05503900 Sao Paulo, SP - Brazil

^[2] Fed Univ Minas Gerais UFMG, Inst Biomed Sci, ICB, Biochem & Immunol Dept, BR-31270901 Belo Horizonte, MG - Brazil

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 8, MAR 29 2018.
• Web of Science Citations: 5

Abstract

One of the most important mechanisms for repairing double-strand breaks (DSBs) in model eukaryotes is homologous recombination (HR). Although the genes involved in HR have been found in Trypanosoma brucei and studies have identified some of the proteins that participate in this HR pathway, the recruitment kinetics of the HR machinery onto DNA during DSB repair have not been clearly elucidated in this organism. Using immunofluorescence, protein DNA-bound assays, and DNA content analysis, we established the recruitment kinetics of the HR pathway in response to the DSBs generated by ionizing radiation (IR) in procyclic forms of T. brucei. These kinetics involved the phosphorylation of histone H2A and the sequential recruitment of the essential HR players Exo1, RPA, and Rad51. The process of DSB repair took approximately 5.5 hours. We found that DSBs led to a decline in the G2/M phase after IR treatment, concomitant with cell cycle arrest in the G1/S phase. This finding suggests that HR repairs DSBs faster than the other possible DSB repair processes that act during the G1/S transition. Taken together, these data suggest that the interplay between DNA damage detection and HR machinery recruitment is finely coordinated, allowing these parasites to repair DNA rapidly after DSBs during the late S/G2 proficient phases. (AU)

• FAPESP's process: 13/07467-1 - CeTICS - Center of Toxins, Immune-Response and Cell Signaling
• Grantee: Hugo Aguirre Armelin
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 15/10580-0 - Characterization of intra-S checkpoint in Trypanosoma cells
• Grantee: Maria Carolina Quartim Barbosa Elias Sabbaga
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/24170-5 - DNA replication dynamics in Trypanosoma cruzi: licensing and replication rate characterization
• Grantee: Marcelo Santos da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/50050-2 - How do common and diverged features of the replicative stress response shape the biology of TriTryp parasites?
• Grantee: Maria Carolina Quartim Barbosa Elias Sabbaga
• Support Opportunities: Research Projects - Thematic Grants