Characterization of anti-silencing factor 1 in Leishmania major

• Published in: Memórias do Instituto Oswaldo Cruz 2012-05, Vol.107 (3), p.377-386
• Main Authors: Scher, Ricardo, Garcia, Juliana Bório Ferreira, Pascoalino, Bruno, Schenkman, Sergio, Cruz, Angela Kaysel
• Format: Article
• Language: English
• Subjects: Animals; anti-silencing factor 1; ASF1 gene; Blotting, Western; Cell cycle; Cell Cycle Proteins - genetics; Chaperones; Chromatin remodeling; chromosome 20; DNA damage; DNA Damage - genetics; Electrophoresis, Gel, Two-Dimensional; Flow Cytometry; Gas Chromatography-Mass Spectrometry; Growth rate; Heat shock proteins; histone chaperone; Histone Chaperones - genetics; Histone Chaperones - physiology; Histones; Leishmania major; Leishmania major - anti-silencing factor 1 - histone chaperone; Leishmania major - chemistry; Methane; Mutation - genetics; Nucleosomes; oxidoreductase; Parasites; PARASITOLOGY; Promastigotes; Proteolysis; Protozoan Proteins - genetics; Protozoan Proteins - physiology; Rabbits; Real-Time Polymerase Chain Reaction; Stress; Telomeres; Transcription; TROPICAL MEDICINE; Trypanosoma brucei
• ISSN: 1678-8060; 0074-0276; 1678-8060; 0074-0276
• DOI: 10.1590/S0074-02762012000300013

Anti-silencing factor 1 (ASF1) is a histone chaperone that contributes to the histone deposition during nucleosome assembly in newly replicated DNA. It is involved in chromatin disassembly, transcription activation and in the cellular response to DNA damage. In Leishmania major the ASF1 gene (LmASF1) is located in chromosome 20 and codes for a protein showing 67% of identity with the Trypanosoma brucei TbASF1a. Compared to orthologous proteins, LmASF1 conserves the main residues relevant for its various biological functions. To study ASF1 in Leishmania we generated a mutant overexpressing LmASF1 in L. major. We observed that the excess of LmASF1 impaired promastigotes growth rates and had no impact on cell cycle progress. Differently from yeast, ASF1 overproduction in Leishmania did not affect expression levels of genes located on telomeres, but led to an upregulation of proteins involved in chromatin remodelling and physiological stress, such as heat shock proteins, oxidoreductase activity and proteolysis. In addition, we observed that LmASF1 mutant is more susceptible to the DNA damaging agent, methyl methane sulphonate, than the control line. Therefore, our study suggests that ASF1 from Leishmania pertains to the chromatin remodelling machinery of the parasite and acts on its response to DNA damage.