title: Chromatin organization and remodeling of interstitial telomeric sites during meiosis in the Mongolian gerbil (Meriones unguiculatus).
abstract: Telomeric DNA repeats are key features of chromosomes that allow the maintenance of integrity and stability in the telomeres. However, interstitial telomere sites (ITSs) can also be found along the chromosomes, especially near the centromere, where they may appear following chromosomal rearrangements like Robertsonian translocations. There is no defined role for ITSs, but they are linked to DNA damage-prone sites. We were interested in studying the structural organization of ITSs during meiosis, a kind of cell division in which programmed DNA damage events and noticeable chromatin reorganizations occur. Here we describe the presence of highly amplified ITSs in the pericentromeric region of Mongolian gerbil (Meriones unguiculatus) chromosomes. During meiosis, ITSs show a different chromatin conformation than DNA repeats at telomeres, appearing more extended and accumulating heterochromatin markers. Interestingly, ITSs also recruit the telomeric proteins RAP1 and TRF1, but in a stage-dependent manner, appearing mainly at late prophase I stages. We did not find a specific accumulation of DNA repair factors to the ITSs, such as γH2AX or RAD51 at these stages, but we could detect the presence of MLH1, a marker for reciprocal recombination. However, contrary to previous reports, we did not find a specific accumulation of crossovers at ITSs. Intriguingly, some centromeric regions of metacentric chromosomes may bind the nuclear envelope through the association to SUN1 protein, a feature usually performed by telomeres. Therefore, ITSs present a particular and dynamic chromatin configuration in meiosis, which could be involved in maintaining their genetic stability, but they additionally retain some features of distal telomeres, provided by their capability to associate to telomere-binding proteins.
authors.affiliation: Departamento de Biología, Universidad Autónoma de Madrid, Madrid 28049, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: de la Fuente
authors.affiliation: Department of Genetics and Development, Columbia University Medical Center, New York, New York 10032.
authors.forename: Marcia
authors.initials: M
authors.lastname: Manterola
authors.affiliation: Departamento de Biología, Universidad Autónoma de Madrid, Madrid 28049, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Viera
authors.affiliation: Departamento de Biología, Universidad Autónoma de Madrid, Madrid 28049, Spain.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Parra
authors.affiliation: Department of Cell and Developmental Biology, University of Würzburg, Würzburg D-97074, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Alsheimer
authors.affiliation: Departamento de Biología, Universidad Autónoma de Madrid, Madrid 28049, Spain.
authors.forename: Julio S
authors.initials: JS
authors.lastname: Rufas
authors.affiliation: Departamento de Biología, Universidad Autónoma de Madrid, Madrid 28049, Spain jesus.page@uam.es.
authors.forename: Jesús
authors.initials: J
authors.lastname: Page
mesh_terms: D000818:Animals; D002453:Cell Cycle; D002455:Cell Division; D002503:Centromere / Q000235:genetics / Q000378:metabolism; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D004260:DNA Repair; D005849:Gerbillinae / Q000235:genetics*; D006570:Heterochromatin / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000378:metabolism; D008540:Meiosis / Q000235:genetics*; D009685:Nuclear Envelope / Q000235:genetics; D011995:Recombination, Genetic; D016615:Telomere / Q000235:genetics* / Q000378:metabolism
chemical_list: D002843:Chromatin; D006570:Heterochromatin; D006657:Histones
keywords: Mongolian gerbil; RAP1; TRF1; chromatin; interstitial telomeres; meiosis