title: The nuclear higher-order structure defined by the set of topological relationships between DNA and the nuclear matrix is species-specific in hepatocytes.
abstract: During the interphase the nuclear DNA of metazoan cells is organized in supercoiled loops anchored to constituents of a nuclear substructure or compartment known as the nuclear matrix. The stable interactions between DNA and the nuclear matrix (NM) correspond to a set of topological relationships that define a nuclear higher-order structure (NHOS). Current evidence suggests that the NHOS is cell-type-specific. Biophysical evidence and theoretical models suggest that thermodynamic and structural constraints drive the actualization of DNA-NM interactions. However, if the topological relationships between DNA and the NM were the subject of any biological constraint with functional significance then they must be adaptive and thus be positively selected by natural selection and they should be reasonably conserved, at least within closely related species. We carried out a coarse-grained, comparative evaluation of the DNA-NM topological relationships in primary hepatocytes from two closely related mammals: rat and mouse, by determining the relative position to the NM of a limited set of target sequences corresponding to highly-conserved genomic regions that also represent a sample of distinct chromosome territories within the interphase nucleus. Our results indicate that the pattern of topological relationships between DNA and the NM is not conserved between the hepatocytes of the two closely related species, suggesting that the NHOS, like the karyotype, is species-specific.
authors: Laboratorio de Biología Molecular y Neurociencias, Facultad de Medicina, Universidad Autónoma del Estado de México, Toluca, 50180, Edo. Méx., Mexico.
authors: Evangelina
authors: E
authors: Silva-Santiago
authors: Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacan, 04510, Ciudad de México, Mexico.
authors: Juan Pablo
authors: JP
authors: Pardo
authors: Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacan, 04510, Ciudad de México, Mexico.
authors: Rolando
authors: R
authors: Hernández-Muñoz
authors: Laboratorio de Biología Molecular y Neurociencias, Facultad de Medicina, Universidad Autónoma del Estado de México, Toluca, 50180, Edo. Méx., Mexico. Electronic address: aaa@uaemex.mx.
authors: Armando
authors: A
authors: Aranda-Anzaldo
mesh_terms: D000818:Animals; D004247:DNA / Q000378:metabolism / Q000648:ultrastructure*; D003850:Deoxyribonuclease I / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D022781:Hepatocytes / Q000166:cytology* / Q000502:physiology; D007700:Kinetics; D008297:Male; D008815:Mice, Inbred Strains; D015530:Nuclear Matrix / Q000235:genetics / Q000648:ultrastructure*; D017208:Rats, Wistar; D013045:Species Specificity
chemical_list: D004247:DNA; D003850:Deoxyribonuclease I
keywords: DNA loop; DNA supercoiling; DNA topology; Karyotype; Loop attachment region; Matrix attachment region; Natural selection