title: Preferential in vitro binding of high mobility group proteins 14 and 17 to nucleosomes containing active and DNase I sensitive single-copy genes.
abstract: High mobility group (HMG) proteins 14 and 17 bind to mononucleosomes in vitro, but the exact nature of this binding has not been clearly established. A new method was developed to allow direct membrane transfer of DNA from HMG 14/17 bound and unbound nucleosomes, which have been separated by acrylamide gel electrophoresis. Hybridization analysis of membranes obtained by this method revealed that the HMG 14/17 bound nucleosomes of avian erythrocytes and rat hepatic tumor (HTC) cells were enriched, about 2-fold, in actively transcribed genes and also inactive but DNase I sensitive genes. Nucleosomes containing inactive, DNase I resistant genes were bound by HMG 14/17, but not preferentially. Several factors that have been reported to greatly influence the binding of HMG 14/17 to nucleosomes in vitro were tested and shown to not account for the preferential binding to DNase I sensitive chromatin. These factors include nucleosomal linker DNA length, single-stranded DNA nicks, and DNA bulk hypomethylation. An additional factor, histone acetylation, was preferentially associated with the HMG 14/17 bound chromatin fraction of avian erythrocytes, but it was not associated with the HMG 14/17 bound chromatin fraction of metabolically active HTC cells. The latter finding was true for all kinetic forms of histone acetylation.
mesh_terms: D000107:Acetylation; D000818:Animals; D001667:Binding, Competitive; D002460:Cell Line; D002645:Chickens; D003850:Deoxyribonuclease I / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D005796:Genes; D006609:High Mobility Group Proteins / Q000378:metabolism*; D006657:Histones / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D009707:Nucleosomes / Q000378:metabolism*; D011485:Protein Binding; D014158:Transcription, Genetic
chemical_list: D006609:High Mobility Group Proteins; D006657:Histones; D009707:Nucleosomes; D003850:Deoxyribonuclease I