Localised negative feedback shapes genome-wide patterning of meiotic DNA breaks

Overview

This research investigates the regulatory mechanisms controlling the spatial distribution of programmed DNA double-strand breaks during meiosis in Saccharomyces cerevisiae. Meiotic DSBs, generated by the Spo11 enzyme, are essential for genetic recombination and diversity in sexually reproducing organisms but pose threats to genome stability if improperly regulated. The study focuses on DSB interference, a phenomenon where Tel1 kinase, the yeast orthologue of mammalian ATM kinase, suppresses DSB formation in regions proximal to existing breaks. While DSB interference has been documented as a local regulatory mechanism, its capacity to reshape genome-wide DSB patterning has remained incompletely characterized. The research employs computational modeling combined with genetic and molecular analyses to elucidate how Tel1-mediated negative feedback propagates across chromosomes and influences population-level DSB distributions.

Methods and approach

The investigators developed a quantitative simulation framework to model Tel1-mediated feedback effects on Spo11-catalyzed DSB formation across the yeast genome. This computational approach integrated innate chromosome-specific DSB patterns with interference mechanisms to predict emergent population-level DSB redistribution. Genetic studies examined Tel1 recruitment requirements through analysis of Xrs2, a protein component necessary for Tel1 localization to DSBs, and assessed the requirement for Tel1 kinase activity in the interference process. The research also investigated Rec114, a pro-DSB factor implicated in DSB regulation, through mutagenesis of potential phosphorylation sites to determine whether Rec114 serves as an essential Tel1 substrate. The combined experimental and computational strategy enabled characterization of the spatial range over which interference propagates and identification of molecular components essential to this regulatory mechanism.

Key Findings

The simulation framework demonstrated that innate chromosome-specific DSB patterns, when subjected to Tel1-mediated interference, generate complex population-level redistribution of DSBs across the genome. The analysis defined the spatial range over which DSB interference propagates, establishing quantitative parameters for this regulatory process. Experimental evidence confirmed that the interference mechanism requires both Tel1 recruitment to DSBs via Xrs2 and Tel1 kinase activity, identifying critical molecular dependencies. While Rec114 was found to contribute to DSB regulation, mutagenesis of candidate phosphorylation sites indicated that Rec114 is not an essential target of Tel1 kinase in the interference pathway. These findings reveal that local negative feedback exerted by Tel1 produces broad-scale, emergent patterning effects that extend beyond immediately adjacent chromosomal regions, fundamentally altering genome-wide DSB distributions through a propagating inhibitory signal.

Implications

The findings establish that localized negative feedback mechanisms can drive emergent, genome-scale patterning of DSB formation during meiosis. This regulatory architecture has significant implications for understanding how cells balance the competing demands of generating sufficient genetic diversity through recombination while maintaining genome stability. The Tel1-mediated interference system represents a fundamental control mechanism that influences recombination initiation patterns and, by extension, the distribution of genetic variation transmitted across generations. The discovery that local DSB formation triggers spatially propagating inhibitory signals that reshape population-level DSB landscapes provides a mechanistic framework for understanding heterogeneity in recombination patterns. These insights into meiotic DSB regulation may inform understanding of related processes in mammalian meiosis, where ATM kinase performs analogous functions, and contribute to broader understanding of how feedback mechanisms generate emergent spatial patterns in genome-modifying processes.