Post-meiotic DNA double-strand breaks occur in Tetrahymena, and require Topoisomerase II and Spo11

Takahiko Akematsu, Yasuhiro Fukuda, Jyoti Garg, Jeffrey S. Fillingham, Ronald E. Pearlman, Josef Loidl

    Research output: Contribution to journalArticlepeer-review

    25 Citations (Scopus)

    Abstract

    Based on observations of markers for DNA lesions, such as phosphorylated histone H2AX (γH2AX) and open DNA ends, it has been suggested that post-meiotic DNA double-strand breaks (PM-DSBs) enable chromatin remodeling during animal spermiogenesis. However, the existence of PM-DSBs is unconfirmed, and the mechanism responsible for their formation is unclear. Here, we report the first direct observation of programmed PM-DSBs via the electrophoretic separation of DSB-generated DNA fragments in the ciliate Tetrahymena thermophila. These PM-DSBs are accompanied by switching from a heterochromatic to euchromatic chromatin structure in the haploid pronucleus. Both a topoisomerase II paralog with exclusive pronuclear expression and Spo11 are prerequisites for PM-DSB induction. Reduced PM-DSB induction blocks euchromatin formation, characterized by histone H3K56 acetylation, leading to a failure in gametic nuclei production. We propose that PM-DSBs are responsible for histone replacement during the reprogramming of generative to undifferentiated progeny nuclei.

    Original languageEnglish
    Article numbere26176
    JournaleLife
    Volume6
    DOIs
    Publication statusPublished - 2017 Jun 16

    ASJC Scopus subject areas

    • Neuroscience(all)
    • Immunology and Microbiology(all)
    • Biochemistry, Genetics and Molecular Biology(all)

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