UMMS Affiliation

Department of Cell Biology; Department of Anatomy

Date

5-4-2000

Document Type

Article

Subjects

Actins; Animals; Bone and Bones; Cell Adhesion; Cell Survival; Cells, Cultured; Macrophage Colony-Stimulating Factor; *Mutation; Osteoblasts; Osteopetrosis; Phenotype; Protein Isoforms; RNA, Messenger; Rats; Rats, Mutant Strains; Signal Transduction

Disciplines

Anatomy | Cell Biology

Abstract

We have shown that in the osteopetrotic rat mutation toothless (tl) osteoblasts are absent from older bone surfaces in mutants and that mutant osteoblasts in vivo lack the prominent stress fiber bundles polarized along bone surfaces in osteoblasts from normal littermates. Our recent data demonstrate that in normal osteoblasts in vitro beta- and gamma-actin mRNAs have different, characteristic intracellular distributions and that tl (mutant) osteoblasts fail to differentially sort these mRNAs. Because bone resorption and formation are highly interdependent and injections of CSF-1, a growth factor, increase bone resorption and growth in tl rats, we examined the effects of CSF-1 treatment on osteoblast survival and ultrastructure in vivo and ability to sort actin mRNAs in vitro. Neonatal CSF-1 treatment of mutants restores osteoblasts on older bone surfaces, normalizes the intracellular distribution of stress fibers in osteoblasts in vivo and promotes normal sorting of beta-actin mRNA in mutant osteoblasts in vitro without normalizing gamma-actin distribution. These data suggest the beta- and gamma-actin mRNAs in osteoblasts are sorted by different mechanisms and that the differential sorting of beta-actin mRNA is related to the characteristic polarization of stress fibers in osteoblasts and their survival on bone surfaces. This experimental system can be used to explore the relationships and regulation of these aspects of cell and tissue biology.

Rights and Permissions

Citation: Int J Dev Biol. 2000 Feb;44(2):201-7.

Related Resources

Link to Article in PubMed

Journal Title

The International journal of developmental biology

PubMed ID

10794078

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