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The natural absence of RPA1N domain did not impair Leishmania amazonensis RPA-1 participation in DNA damage response and telomere protection.
Universidade Estadual Paulista (UNESP)
We have previously shown that the subunit 1 of Leishmania amazonensis RPA (LaRPA-1) alone binds the G-rich telomeric strand and is structurally different from other RPA-1. It is analogous to telomere end-binding proteins described in model eukaryotes whose homologues were not identified in the protozoan's genome. Here we show that LaRPA-1 is involved with damage response and telomere protection although it lacks the RPA1N domain involved with the binding with multiple checkpoint proteins. We induced DNA double-strand breaks (DSBs) in Leishmania using phleomycin. Damage was confirmed by TUNEL-positive nuclei and triggered a G1/S cell cycle arrest that was accompanied by nuclear accumulation of LaRPA-1 and RAD51 in the S phase of hydroxyurea-synchronized parasites. DSBs also increased the levels of RAD51 in non-synchronized parasites and of LaRPA-1 and RAD51 in the S phase of synchronized cells. More LaRPA-1 appeared immunoprecipitating telomeres in vivo and associated in a complex containing RAD51, although this interaction needs more investigation. RAD51 apparently co-localized with few telomeric clusters but it did not immunoprecipitate telomeric DNA. These findings suggest that LaRPA-1 and RAD51 work together in response to DNA DSBs and at telomeres, upon damage, LaRPA-1 works probably to prevent loss of single-stranded DNA and to assume a capping function.
Issue Date: 
Parasitology, v. 140, n. 4, p. 547-559, 2013.
Time Duration: 
  • nucleic acid synthesis inhibitor
  • phleomycin
  • protozoal protein
  • cell cycle checkpoint
  • double stranded DNA break
  • drug effect
  • genetics
  • Leishmania
  • metabolism
  • nick end labeling
  • telomere
  • Cell Cycle Checkpoints
  • DNA Breaks, Double-Stranded
  • In Situ Nick-End Labeling
  • Nucleic Acid Synthesis Inhibitors
  • Phleomycins
  • Protozoan Proteins
  • Telomere
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Appears in Collections:Artigos, TCCs, Teses e Dissertações da Unesp

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