CRL4 regulates recombination and synaptonemal complex aggregation in the Caenorhabditis elegans germline

• Published in: PLoS genetics Vol. 15; no. 11; p. e1008486
• Main Authors: Alleva, Benjamin, Clausen, Sean, Koury, Emily, Hefel, Adam, Smolikove, Sarit
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 18.11.2019; Public Library of Science (PLoS)
• Subjects: Animals; Backup software; Biology; Biology and life sciences; Biotechnology; Caenorhabditis elegans; Caenorhabditis elegans - genetics; Caenorhabditis elegans Proteins - genetics; Chromosome Pairing - genetics; Chromosome Segregation - genetics; Chromosomes; Crossing Over, Genetic; Cullin; Deoxyribonucleic acid; Deregulation; DNA; DNA Breaks, Double-Stranded; DNA damage; Endodeoxyribonucleases - genetics; Enzymes; Genomes; Genomics; Germ Cells - growth & development; Homologous recombination; Homologous Recombination - genetics; Ligases; Ligases - genetics; Meiosis; Meiosis - genetics; Meiotic Prophase I - genetics; Nematodes; Nuclease; Prophase; Protein structure; Proteins; Research and Analysis Methods; Synaptonemal complex; Synaptonemal Complex - genetics; Transposition; Transposons; Ubiquitin; Ubiquitin-protein ligase; Ubiquitination; Yeast; United States > US; Iowa; Iowa City Iowa
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1008486

To maintain the integrity of the genome, meiotic DNA double strand breaks (DSBs) need to form by the meiosis-specific nuclease Spo11 and be repaired by homologous recombination. One class of products formed by recombination are crossovers, which are required for proper chromosome segregation in the first meiotic division. The synaptonemal complex (SC) is a protein structure that connects homologous chromosomes during meiotic prophase I. The proper assembly of the SC is important for recombination, crossover formation, and the subsequent chromosome segregation. Here we identify the components of Cullin RING E3 ubiquitin ligase 4 (CRL4) that play a role in SC assembly in Caenorhabditis elegans. Mutants of the CRL4 complex (cul-4, ddb-1, and gad-1) show defects in SC assembly manifested in the formation of polycomplexes (PCs), impaired progression of meiotic recombination, and reduction in crossover numbers. PCs that are formed in cul-4 mutants lack the mobile properties of wild type SC, but are likely not a direct target of ubiquitination. In C. elegans, SC assembly does not require recombination and there is no evidence that PC formation is regulated by recombination as well. However, in one cul-4 mutant PC formation is dependent upon early meiotic recombination, indicating that proper assembly of the SC can be diminished by recombination in some scenarios. Lastly, our studies suggest that CUL-4 deregulation leads to transposition of the Tc3 transposable element, and defects in formation of SPO-11-mediated DSBs. Our studies highlight previously unknown functions of CRL4 in C. elegans meiosis and show that CUL-4 likely plays multiple roles in meiosis that are essential for maintaining genome integrity.