Electron Microscope Studies of Chromatin Subunit Particles

Citation

Kent, Diane Jacalyn (1975) Electron Microscope Studies of Chromatin Subunit Particles. Master's thesis, California Institute of Technology. doi:10.7907/GVT9-N257. https://resolver.caltech.edu/CaltechTHESIS:04202010-093957061

Abstract

Nuclease resistant chromatin subunits (ν bodies) were isolated from rat liver chromatin after digestion with DNAase II. Electron microscope studies showed them to be similar in size to particles which have been isolated from calf thymus chromatin and also to those seen in native chromatin. ν bodies prepared from native chromatin (ν(+F1) and histone F1-depleted chromatin (ν(-F1)), as well as formaldehyde-fixed products from both these digestions (ν(FF + F1) and ν(FF-F1) were similar in size. For ν(+F1) the diameter was 80 ± 17 Å (n = 125); for ν(-F1), 87 ± 19 Å (n = 100); for ν(FF + F1), 96 ± 23 Å (n = 50); and for ν(FF – F1) 81 ± 13 Å (n = 85). Multimer ν-body fractions did not show any obvious dimers, trimers, etc. , of monomer ν bodies. Sheared, isolated chromatin from rat liver was also examined using electron microscopy and was observed as networks of long thin strands (about 15 Å wide), interspersed with regions of either coiled single strands or strands covered with protein.

Thesis Files