Title

Progressive changes in the protein composition of the nuclear matrix during rat osteoblast differentiation

UMMS Affiliation

Department of Cell Biology

Date

6-1-1990

Document Type

Article

Subjects

Animals; Cell Differentiation; Cells, Cultured; Electrophoresis, Gel, Two-Dimensional; Gene Expression; Histones; Molecular Weight; Nuclear Matrix; Nuclear Proteins; Osteoblasts; Osteocalcin; RNA, Messenger; Rats; Rats, Inbred Strains; Time Factors

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Primary cultures of fetal rat calvarial osteoblasts undergo a developmental sequence with respect to the temporal expression of genes encoding osteoblast phenotypic markers. Based on previous suggestions that gene-nuclear matrix associations are involved in regulating cell- and tissue-specific gene expression, we investigated the protein composition of the nuclear matrix during this developmental sequence by using high-resolution two-dimensional gel electrophoresis. The nuclear matrix was isolated at times during a 4-week culture period that represent the three principal osteoblast phenotypic stages: proliferation, extracellular matrix (ECM) maturation, and mineralization. The most dramatic changes in the nuclear matrix protein patterns occurred during transitions from the proliferation to the ECM maturation stage and from ECM maturation to the mineralization period, with only minor variations in the profiles within each period. These stage-specific changes, corresponding to the major transition points in gene expression, indicate that the nuclear matrix proteins reflect the progressive differentiation of the bone cell phenotype. Subcultivation of primary cells delays mineralization, and a corresponding delay was observed for the nuclear matrix protein patterns. Thus, the sequential changes in protein composition of the nuclear matrix that occur during osteoblast differentiation represent distinct stage-specific markers for maturation of the osteoblast to an osteocytic cell in a bone-like mineralized ECM. These changes are consistent with a functional involvement of the nuclear matrix in mediating modifications of developmental gene expression.

Rights and Permissions

Citation: Proc Natl Acad Sci U S A. 1990 Jun;87(12):4605-9.

Related Resources

Link to Article in PubMed

Journal Title

Proceedings of the National Academy of Sciences of the United States of America

PubMed ID

2352938