The role of the nuclear protein matrix during development of rabbit
granulocytes
CE Eastment, RB Scott, KR Shelton and JL Haar
A proteinaceous nuclear substructure (nuclear protein matrix or nuclear
pore complex-lamina) has been described in a number of cells and may be a
universal feature of cell nuclei. We have investigated the nuclear protein
matrix (NPM) in the rabbit blood granulocyte and its precursor cells to
determine (A) whether the NPM composition is similar to other cells that
have been studied and (B) to determine whether the dramatic morphological
changes that the granulocyte nucleus undergoes during cell maturation are
related to changes in the composition or structure of the NPM. NPM
preparations from rabbit granulocytes were similar but not identical to
those found in HeLa cells or rat liver nuclei. The NPM structure of more
mature cells retained more DNA during the isolation procedures than did
immature cell NPMs, and the DNA was less accessible to DNAse in the mature
cell nuclei. Scanning and transmission electron microscopy revealed a
continuous outer covering of the NPM preparation and a lattice-like
internal structure. Recognizable nuclear form persisted although the
preparations represented less than 20% of the original nuclear protein. NPM
preparations from mature cells were similar in overall dimensions and
internal structure to NPM from immature cells, suggesting reexpansion
during isolation of a previously compacted NPM structure in segmented
neutrophils. NPM proteins are synthesized primarily in early stages of cell
development. The NPM appears to play a major, but passive, structural role
in the nuclear changes observed during maturation of granulocytes.
Volume 57,
Issue 4,
pp. 747-757,
04/01/1981
Copyright © 1981 by The American Society of Hematology
