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Journal ArticleDOI

Runt Homology Domain Proteins in Osteoblast Differentiation: AML3/CBFA1 Is a Major Component of a Bone-Specific Complex

TLDR
It is demonstrated that in primary rat osteoblasts AML‐3 is the AML family member present in the osteoblast‐specific complex and that the activity of rhd proteins is required for completion of osteobasts differentiation.
Abstract
The AML/CBFA family of runt homology domain (rhd) transcription factors regulates expression of mammalian genes of the hematopoietic lineage. AML1, AML2 and AML3 are the three AML genes identified to date which influence myeloid cell growth and differentiation. Recently AML-related proteins were identified in an osteoblast-specific promoter binding complex that functionally modulates bone-restricted transcription of the osteocalcin gene. In the present study we demonstrate that in primary rat osteoblasts AML-3 is the AML family member present in the osteoblast-specific complex. Antibody specific for AML-3 completely supershifts this complex, in contrast to antibodies with specificity for AML-1 or AML-2, AML-3 is present as a single 5.4 kb transcript in bone tissues. To establish the functional involvement of AML factors in osteoblast differentiation, we pursued antisense strategies to alter expression of rhd genes. Treatment of osteoblast cultures with rhd antisense oligonucleotides significantly decreased three parameters which are linked to differentiation of normal diploid osteoblasts: the representation of alkaline phosphatase-positive cells, osteocalcin production, and the formation of mineralized nodules. Our findings indicate that AML-3 is a key transcription factor in bone cells and that the activity of rhd proteins is required for completion of osteoblast differentiation.

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Journal ArticleDOI

Canonical WNT Signaling Promotes Osteogenesis by Directly Stimulating Runx2 Gene Expression

TL;DR: It is proposed that WNT/TCF1 signaling, like bone morphogenetic protein/transforming growth factor-β signaling, activates Runx2 gene expression in mesenchymal cells for the control of osteoblast differentiation and skeletal development.
Journal ArticleDOI

Regulation of osteoblast differentiation mediated by bone morphogenetic proteins, hedgehogs, and Cbfa1.

TL;DR: In this article, the authors reviewed the regulation of osteoblast differentiation mediated by the local factors such as bone morphogenetic proteins (BMPs) and hedgehogs and the transcription factor, core-binding factor alpha-1 (Cbfa1).
Journal ArticleDOI

Regulation of bone development and extracellular matrix protein genes by RUNX2.

TL;DR: RUNX2 directs pluripotent mesenchymal cells to the osteoblast lineage, triggers the expression of major bone matrix protein genes, and keeps the osteoblasts in an immature stage, but does not play a major role in the maintenance of theexpression of Col1a1 or Bglap in mature osteoblast.
Journal ArticleDOI

Isolation and characterization of MC3T3-E1 preosteoblast subclones with distinct in vitro and in vivo differentiation/mineralization potential.

TL;DR: Interestingly, subclones with both high and low differentiation potential produced similar amounts of collagen in culture and expressed comparable basal levels of mRNA encoding Osf2/Cbfa1, an osteoblast‐related transcription factor, and there was no clear relationship between levels of this message and induction of mRNAs for other differentiation markers.
References
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Journal ArticleDOI

AML1, the Target of Multiple Chromosomal Translocations in Human Leukemia, Is Essential for Normal Fetal Liver Hematopoiesis

TL;DR: The results suggest that AML1-regulated target genes are essential for definitive hematopoiesis of all lineages, and that this defect was intrinsic to the stem cells in that AMl1-/-ES cells failed to contribute to hematocerosis in chimeric animals.
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Progressive development of the rat osteoblast phenotype in vitro: Reciprocal relationships in expression of genes associated with osteoblast proliferation and differentiation during formation of the bone extracellular matrix

TL;DR: The relationship of cell proliferation to the temporal expression of genes characterizing a developmental sequence associated with bone cell differentiation was examined in primary diploid cultures of fetal calvarial derived osteoblasts by the combined use of autoradiography, histochemistry, biochemistry, and mRNA assays of osteoblast cell growth and phenotypic genes.

Progressive Development of the Rat Osteoblast Phenotype In Vitro: Reciprocal Relationships in Expression of Genes Associated With Osteoblast Proliferation and Differentiation During Formation of the

TL;DR: In this article, the relationship of cell proliferation to the temporal expression of genes characterizing a developmental sequence associated with bone cell differentiation was examined in primary diploid cultures of fetal calvarial derived osteoblasts by the combined use of autoradiography, histochemistry, biochemistry, and mRNA assays of osteoblast cell growth and phenotypic genes.
Journal ArticleDOI

Disruption of the Cbfa2 gene causes necrosis and hemorrhaging in the central nervous system and blocks definitive hematopoiesis.

TL;DR: The CBFA2 (AML1) gene encodes a DNA-binding subunit of the heterodimeric core-binding factor, which significantly reduces the number of progenitors for erythroid and myeloid cells.
Journal ArticleDOI

PEBP2/PEA2 represents a family of transcription factors homologous to the products of the Drosophila runt gene and the human AML1 gene.

TL;DR: Evidence indicated that PEBP2 functions as a transcriptional activator and is involved in regulation of T-cell-specific gene expression, a newly discovered family of transcription factor.
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