title: Probing the free space within rat and chicken chromatin with active and passive probes.
abstract: The cavity systems within chicken erythrocyte nuclei and rat liver nuclei were compared using passive probes of radioactive glycogen and active probes of nuclease-armed-glycogen. The passive probe curves have a form that indicates that they are due to passive occupation of spaces and not due to the effects of a limiting membrane. The technique of probing nuclei with glycogen armed with a small enzyme is described. The chicken erythrocytes appeared to have 11-15-nm and 4-5-nm cacity systems similar to those we have previously reported in rat nuclei. Evidence is presented to show that the bridge DNA is enclosed within the 4-5 nm cavities in both rat liver and chicken erythrocyte nuclei. Minor differences between the rat liver and chicken erythrocyte nuclear cavity systems are noted in the region of 5-8 nm. A relatively mild procedure is described for preparing chicken erythrocyte nuclei.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure; D002645:Chickens; D002843:Chromatin / Q000648:ultrastructure*; D004247:DNA; D004912:Erythrocytes / Q000648:ultrastructure; D005260:Female; D006003:Glycogen; D008099:Liver / Q000648:ultrastructure; D008722:Methods; D008836:Micrococcal Nuclease; D051381:Rats
chemical_list: D002843:Chromatin; D006003:Glycogen; D004247:DNA; D008836:Micrococcal Nuclease