Synaptonemal complex formation produces a particular arrangement of the lateral element-associated DNA

• Published in: Experimental cell research 2021-02, Vol.399 (2), p.112455-112455, Article 112455
• Main Authors: Ortiz, Rosario, Chavero, Silvia Juárez, Echeverría, Olga M., Hernandez-Hernandez, Abrahan
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; CHROMATIDS; CHROMOSOMES; Crossover interference; DNA; DNA REPAIR; MEIOSIS; Meiotic recombination; MICE; NAMA-Ur; RECOMBINATION; Synaptonemal complex; TESTES
• ISSN: 0014-4827; 1090-2422
• DOI: 10.1016/j.yexcr.2020.112455

During meiosis, homologous chromosomes exchange genetic material. This exchange or meiotic recombination is mediated by a proteinaceous scaffold known as the Synaptonemal complex (SC). Any defects in its formation produce failures in meiotic recombination, chromosome segregation and meiosis completion. It has been proposed that DNA repair events that will be resolved by crossover between homologous chromosomes are predetermined by the SC. Hence, structural analysis of the organization of the DNA in the SC could shed light on the process of crossover interference. In this work, we employed an ultrastructural DNA staining technique on mouse testis and followed nuclei of pachytene cells. We observed structures organized similarly to the SCs stained with conventional techniques. These structures, presumably the DNA in the SCs, are delineating the edges of both lateral elements and no staining was observed between them. DNA in the LEs resembles two parallel tracks. However, a bubble-like staining pattern in certain regions of the SC was observed. Furthermore, this staining pattern is found in SCs formed between non-homologous chromosomes, in SCs formed between sister chromatids and in SCs without lateral elements, suggesting that this particular organization of the DNA is determined by the synapsis of the chromosomes despite their lack of homology or the presence of partially formed SCs. •The NAMA-Ur method can be used to analyze the DNA associated to the synaptonemal complex.•The DNA associated to the synaptonemal complex display bubble-like organization.•Formation of the synaptonemal complex is enough to produce the bubble-like organization of the DNA.•Synaptonemal complex without lateral elements produce similar organization of its associated DNA.