SUMO is a pervasive regulator of meiosis.

Nikhil R Bhagwat,Jay V Boinapalli,Srujan Kopparapu,Sean R Collins,Owen Richard Davies,Shannon N Owens,Nevan J Krogan,Neil Hunter,Meghan Mahalawat,Masaru Ito,Philip Poa,Alexander Ditzel,Jeffrey R Johnson

doi:10.7554/elife.57720

Abstract

Protein modification by SUMO helps orchestrate the elaborate events of meiosis to faithfully produce haploid gametes. To date, only a handful of meiotic SUMO targets have been identified. Here, we delineate a multidimensional SUMO-modified meiotic proteome in budding yeast, identifying 2747 conjugation sites in 775 targets, and defining their relative levels and dynamics. Modified sites cluster in disordered regions and only a minority match consensus motifs. Target identities and modification dynamics imply that SUMOylation regulates all levels of chromosome organization and each step of meiotic prophase I. Execution-point analysis confirms these inferences, revealing functions for SUMO in S-phase, the initiation of recombination, chromosome synapsis and crossing over. K15-linked SUMO chains become prominent as chromosomes synapse and recombine, consistent with roles in these processes. SUMO also modifies ubiquitin, forming hybrid oligomers with potential to modulate ubiquitin signaling. We conclude that SUMO plays diverse and unanticipated roles in regulating meiotic chromosome metabolism.

Highlights

Meiosis precisely halves the chromosome complement enabling parents to contribute to their progeny while maintaining a stable ploidy through successive generations (Hunter, 2015)
We employed the method of Berchowitz et al in which cells synchronize in G0 before meiosis is triggered by inducing expression of the master regulator, IME1, which is under control of the copper-inducible CUP1 promoter (PCUP1-IME1; Figure 1A; Berchowitz et al, 2013)
This was achieved by reversibly arresting cells using an estradiol inducible NDT80 gene (PGAL-NDT80) (Benjamin et al, 2003), which encodes a meiosis-specific transcription factor required for progression beyond pachytene

Summary

Introduction

Meiosis precisely halves the chromosome complement enabling parents to contribute to their progeny while maintaining a stable ploidy through successive generations (Hunter, 2015). In Caenorhabditis elegans, SUMO targets components of the chromosome congression/segregation ring complexes (Davis-Roca et al, 2018; Pelisch et al, 2017) This paucity of examples underscores how understanding meiotic SUMOylation has been impeded by inefficient piecemeal approaches to identifying targets and mapping the sites of SUMO conjugation. Meiosis-specific aspects of chromosome metabolism are strongly represented pointing to roles for SUMO in regulating recombination, chromosome synapsis, and segregation These inferences were explored by acutely inactivating de novo SUMOylation at different times during meiotic prophase. This analysis reveals distinct execution points for SUMO modification and identifies roles in the onset of S-phase, DSB formation, crossing over, and chromosome synapsis. Our analysis delineates a diverse and dynamic meiotic SUMO-modified proteome and provides a rich resource toward a mechanistic understanding of how SUMO regulates the complex events of meiosis

Results and discussion

Materials and methods

Funding Funder