title: Digestion by micrococcal nuclease of mouse submandibular-salivary-gland chromatin.
abstract: Nucleic prepared from mouse submandibular salivary gland show marked fragility during isolation. Hwever, intact nuclei relatively free from cytoplasmic contamination were obtained by homogenization in buffers containing 0.88 M-sucrose, Ca2+, spermine, spermidine and the proteinase inhibitor aprotinin, followed by centrifugation through 2.2 M-sucrose. The kinetics of digestion by the micrococcal nuclease of chromatin in these nuclei are similar to those of chromatin from mouse liver nuclei. Base-pair size analysis of the solubilized DNA from both organs shows a stable high-molecular weight species of chromatin, which is further digested to mononucleosome and subnucleosome species. With extensive digestion the chromatin becomes insoluble. The mononucleosomes produced from salivary-gland chromatin after the inhibition of endogenous proteinase activity exhibit an s20,w value of 11S and contain histones H1, H2A, H2B, H3 and H4.
mesh_terms: D000818:Animals; D001482:Base Composition; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000648:ultrastructure; D002499:Centrifugation, Density Gradient; D002843:Chromatin; D004247:DNA / Q000032:analysis; D008099:Liver / Q000032:analysis; D008297:Male; D051379:Mice; D008836:Micrococcal Nuclease; D013363:Submandibular Gland / Q000032:analysis* / Q000648:ultrastructure
chemical_list: D002843:Chromatin; D004247:DNA; D008836:Micrococcal Nuclease