Journal Article

Dynamic localization of SPO11-1 and conformational changes of meiotic axial elements during recombination initiation of maize meiosis

Lee, Ding Hua, Williams-Carrier, Rosalind, Barkan, Alice, Gomez Angoa, Ana Karen, Cande, W. Zacheus, United States Department of Health & Human ServicesNational Institutes of Health (NIH) - USAGM48547Universidad Nacional Autonoma de MexicoPAPIIT IA201217National Science Foundation (NSF)IOS-1339130Taiwan Ministry of Science and Technology 107-2923-B-002-001-MY4103-2311-B-001-014, Timofejeva, Ljudmilla, N.I. Vavilov Research Institute of Plant Industry (VIR (BИP)), Ronceret, Arnaud, Corteva Agriscience, Wang, Chung-Ju Rachel, Golubovskaya, Inna, Wang, Chiting, Meeley, Robert, Instituto de Biotecnología / UNAM Cuernavaca, Kao, Yu-Hsin, Department of Molecular and Cell Biology and Plant and Microbial Biology ; University of California [Berkeley] (UC Berkeley) ; University of California (UC)-University of California (UC), Institute of Plant and Microbial Biology ; Academia Sinica, Institute of Molecular Biology ; University of Oregon [Eugene], Ku, Jia-Chi, Kremling, Karl, ANR-17-CE12-0032,ESSPOIR,Comprendre la structure de SPO11, s

2020

Overview

Meiosis is essential during sexual reproduction to produce haploid gametes. Recombination is the most crucial step during meiotic prophase I. It enables pairing of homologous chromosomes prior to their reductional division and generates new combinations of genetic alleles for transmission to the next generation. Meiotic recombination is initiated by generating DNA double-strand breaks (DSBs) via SPO11, a topoisomerase-related enzyme. The activity, timing and location of this DSB machinery must be controlled precisely, but how this is achieved remains obscure. Here, we show dynamic localization of SPO11-1 on chromatin during meiotic initiation in maize, yet a similar number of SPO11-1 is able to load onto axial elements (AEs), which accompanies a structural change of the AEs of wild-type meiotic chromosomes. Interestingly, loss of SPO11-1 not only affects DSB formation but also impairs structural alterations of AEs, resulting in abnormally long and curly AEs during early meiosis. Our study provides new insights into SPO11-1 localization during recombination initiation and suggests an intimate relationship between DSB formation and AE structural changes.Meiotic double-strand breaks (DSBs) are generated by the evolutionarily conserved SPO11 complex in the context of chromatin loops that are organized along axial elements (AEs) of chromosomes. However, how DSBs are formed with respect to chromosome axes and the SPO11 complex remains unclear in plants. Here, we confirm that DSB and bivalent formation are defective in maize spo11-1 mutants. Super-resolution microscopy demonstrates dynamic localization of SPO11-1 during recombination initiation, with variable numbers of SPO11-1 foci being distributed in nuclei but similar numbers of SPO11-1 foci being found on AEs. Notably, cytological analysis of spo11-1 meiocytes revealed an aberrant AE structure. At leptotene, AEs of wild-type and spo11-1 meiocytes were similarly curly and discontinuous. However, during early zygotene, wild-type AEs become uniform and exhibit shortened axes, whereas the elongated and curly AEs persisted in spo11-1 mutants, suggesting that loss of SPO11-1 compromised AE structural maturation. Our results reveal an interesting relationship between SPO11-1 loading onto AEs and the conformational remodeling of AEs during recombination initiation.

• Publisher: CCSD,Public Library of Science,Public Library of Science (PLoS)
• Subject: Biology and Life Sciences / Cell division / Chromatin / Chromosomes / Deoxyribonucleic acid / DNA / DNA damage / DNA methylation / Funding / Genetics / Kinases / Life Sciences / Localization / Meiosis / Molecular biology / Mutants / Proteins / Recombination / Research and Analysis Methods / Yeast / Zygotene
• ISBN: 0005313637000