Native chromatin and damage induced by nuclease.
Differential scanning calorimetry, gel electrophoresis and polarized light scattering of chromatin prepared by different methods have been carried out at low and high ionic strength, before and after shearing. These noninvasive studies, when compared to the ones similarly conducted in the corresponding native nuclei, conclusively point to the artefactual nature of chromatin prepared by limited nuclease digestion, which has no resemblence with the in situ chromatin-DNA structure being instead preserved by lysis of native nuclei and by subsequent sedimentation and suspension of the viscous chromatin mass. Native nucleofilaments appear longer than 200 nucleosomes and yield, from thermodynamic and optical standpoints, a tight quaternary structure maintained even at 0.01 M.
Nicolini
C
C
Institute of Biophysics, Medical School, University of Genova, Italy.
Vergani
L
L
Diaspro
A
A
Scelza
P
P
D000818:Animals; D002152:Calorimetry, Differential Scanning; D002843:Chromatin / Q000187:drug effects*; D004249:DNA Damage; D008027:Light; D008836:Micrococcal Nuclease / Q000378:metabolism*; D051381:Rats; D012542:Scattering, Radiation
D002843:Chromatin; D008836:Micrococcal Nuclease