title: Evidence for binding of extrachromosomal DNA sequences to nuclear matrix proteins in multidrug-resistant KB-V1 cells.
abstract: Multidrug-resistant KB-V1 cells carry amplified mdrl gene sequences located in an extrachromosomal compartment (on episomes). Since episomes do not contain centromeric or telomeric sequences it is unclear whether they are able to bind to nuclear matrix proteins that may regulate episomal gene expression. Using high salt treatments followed by in situ hybridization and dot blot analyses we found evidence for direct binding of episomal DNA to nuclear matrix proteins. This binding could only be reversed after incubation with trypsin or proteinase K as determined by contour-clamped homogeneous electric field (CHEF) electrophoresis. Our findings are consistent with the concept that circular extrachromosomal DNA may not only reintegrate into nuclear DNA but may also be subject to functional control by regulatory proteins within the nuclear matrix.
authors.affiliation: University of California San Diego Cancer Center 92103.
authors.forename: F
authors.initials: F
authors.lastname: Thiebaut
authors.forename: A R
authors.initials: AR
authors.lastname: Hanauske
authors.forename: D D
authors.initials: DD
authors.lastname: Von Hoff
mesh_terms: D002460:Cell Line; D004247:DNA / Q000378:metabolism*; D004351:Drug Resistance / Q000235:genetics*; D004586:Electrophoresis; D019286:Endopeptidase K; D017403:In Situ Hybridization; D008856:Microscopy, Fluorescence; D015530:Nuclear Matrix / Q000737:chemistry; D009687:Nuclear Proteins / Q000378:metabolism*; D010957:Plasmids; D012697:Serine Endopeptidases / Q000494:pharmacology; D012965:Sodium Chloride / Q000008:administration & dosage / Q000494:pharmacology; D014357:Trypsin / Q000494:pharmacology
chemical_list: D009687:Nuclear Proteins; D012965:Sodium Chloride; D004247:DNA; D012697:Serine Endopeptidases; D014357:Trypsin; D019286:Endopeptidase K