Meiotic prophase length modulates Tel1-dependent DNA double-strand break interference.

Area of Science:

• Genetics
• Molecular Biology
• Cell Biology

Background:

• Meiosis involves DNA double-strand breaks (DSBs) initiated by Spo11 at hotspots.
• DSB formation triggers DNA damage response kinases like Tel1/ATM, which inhibit nearby Spo11 activity (DSB interference).
• In S. cerevisiae, DSB formation exhibits clustering over short distances, suggesting localized priming of sub-chromosomal domains.

Purpose of the Study:

• To investigate the role of meiotic prophase timing in DSB clustering.
• To determine if DSB clustering is influenced by the NDT80 transcription factor and Tel1 kinase.
• To elucidate the mechanisms underlying Spo11-DSB formation and its spatial distribution during meiosis.

Main Methods:

• Deletion of the NDT80 transcription factor to extend meiotic prophase timing.
• Analysis of genome-wide Spo11-DSB formation maps in wild-type, ndt80Δ, and tel1Δ yeast strains.
• Comparison of DSB patterns under conditions of extended versus normal meiotic prophase duration.

Main Results:

• Deletion of NDT80 abolished DSB clustering, supporting the hypothesis that extended prophase allows for equilibration of DSB potential.
• In tel1Δ cells with NDT80 present, DSB formation skewed towards pericentromeric regions, indicating preferential priming.
• This priming-dependent skewing was abolished in ndt80Δ tel1Δ double mutants, reinforcing the role of prophase timing.

Conclusions:

• Meiotic prophase timing significantly impacts the spatial distribution of DSBs, with extended timing reducing clustering.
• DSB clustering arises from the stochastic nature of Spo11 activity within a limited temporal window and is influenced by sub-chromosomal priming.
• Tel1/ATM kinase plays a dual role in DSB interference and meiotic prophase checkpoint control, affecting DSB clustering, particularly in tel1Δ mutants.