TGF-β1 modifications in nuclear matrix proteins of osteoblasts during differentiation

✍ Scribed by Danielle Lindenmuth; André J. van Wijnen; Sheldon Penman; Janet L. Stein; Gary S. Stein; Jane B. Lian

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 592 KB
• Volume: 69
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/(sici)1097-4644(19980601)69:3<291::aid-jcb7>3.0.co;2-m

✦ Synopsis

Nuclear matrix protein (NMP) composition of osteoblasts shows distinct two-dimensional gel electrophoretic profiles of labeled proteins as a function of stages of cellular differentiation. Because NMPs are involved in the control of gene expression, we examined modifications in the representation of NMPs induced by TGF-␤1 treatment of osteoblasts to gain insight into the effects of TGF-␤ on development of the osteoblast phenotype. Exposure of proliferating fetal rat calvarial derived primary cells in culture to TGF-␤1 for 48 h (day 4-6) modifies osteoblast cell morphology and proliferation and blocks subsequent formation of mineralized nodules. Nuclear matrix protein profiles were very similar between control and TGF-␤-treated cultures until day 14, but subsequently differences in nuclear matrix proteins were apparent in TGF-␤-treated cultures. These findings support the concept that TGF-␤1 modifies the final stage of osteoblast mineralization and alters the composition of the osteoblast nuclear matrix as reflected by selective and TGF-␤-dependent modifications in the levels of specific nuclear matrix proteins. The specific changes induced by TGF-␤ in nuclear matrix associated proteins may reflect specialized mechanisms by which TGF-␤ signalling mediates the alterations in cell organization and nodule formation and/or the consequential block in extracellular mineralization.