Reduced CpG methylation is associated with transcriptional activation of the bone‐specific rat osteocalcin gene in osteoblasts*

Villagra, Alejandro; Gutiérrez, José L.; Paredes, Roberto; Sierra, J M; Puchi, Marcia; Imschenetzky, María; Wijnen, André van; Lian, Jane B.; Stein, Gary S.; Montecino, Martín

doi:10.1002/jcb.10113

Cited by 95 publications

(73 citation statements)

References 32 publications

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“…Considering these findings, the methylation-associated silencing of the ChM-I gene in OBOS and FBOS might be a transformation-related phenomenon. However, it also is likely that the silencing of the ChM-I gene is a physiological phenomenon occurring during the differentiation of mesenchymal cells as demonstrated for other genes (33)(34)(35). We showed that the removal of methylation restored the binding of Sp3 and induced the expression of the ChM-I gene in osteoblastic cells (Fig.…”

Section: Discussionsupporting

confidence: 58%

Methylation in the Core-promoter Region of the Chondromodulin-I Gene Determines the Cell-specific Expression by Regulating the Binding of Transcriptional Activator Sp3

Aoyama

Okamoto

Nagayama

et al. 2004

Journal of Biological Chemistry

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Chondromodulin-I (ChM-I) 1 is a 25-kDa glycoprotein originally purified from bovine epiphyseal cartilage on the basis of growth-promoting activity for chondrocytes (1) and subsequently revealed to be a potent vascular endothelial cell growth inhibitor (2). During embryonal development, the expression of the ChM-I gene is first observed in all of the cartilaginous tissues, which are composed of prehypertrophic chondrocytes (3). As the development proceeds, hypertrophic chondrocytes develop in the center of cartilaginous bone rudiments where the expression of the ChM-I gene shows a marked decrease (3). No expression of the ChM-I gene is observed in bone tissues developing after vascular invasion in the area adjacent to hypertrophic chondrocytes (3). In matured limbs, the expression of the ChM-I gene is limited to cells in the resting, proliferating, and early hypertrophic zone of the growth plate (2-4). These results suggest that the expression of the ChM-I gene is regulated strictly in a cell-and stage-related manner, although the molecular mechanisms leading to this spatiotemporal expression have not been elucidated.Osteosarcoma (OS) is defined as a sarcoma that produces a bone matrix called osteoid, suggesting that the precursor cells of OS are cells of the osteogenic lineage (5). The degree of differentiation as osteoblasts, however, differs considerably among OS ranging from tumors with a large amount of osteoid and expressing a number of bone-related genes such as alkaline phosphatase (ALP) and osteocalcin (OCN) genes, namely osteoblastic OS (OBOS), to tumors in which an osteoid is hardly seen, fibroblastic OS (FBOS) (6 -8). A particular intriguing subtype of OS is chondroblastic OS (CBOS) in which tumor cells directly produce immature cartilage in addition to osteoid (5, 9), suggesting that tumor cells in this subtype have the potential to differentiate into both osteogenic and chondrogenic cells. These clinical findings suggest that the precursor cells of OS range from mesenchymal stem cells to mature osteoblasts and that OS cells can be used as materials to investigate the regulatory mechanisms of cell-and stage-specific genes such as the ChM-I gene.Here we first analyzed the expression of the ChM-I gene in primary OS tumors and cell lines and found that the gene was expressed strongly in CBOS but not in tumors of other subtypes. This result prompted us to investigate the involvement in regulation of the expression of the ChM-I gene of an epigenetic mechanism, which has been studied extensively as the mechanism controlling the expression of cell-and stage-specific genes (10). We found that the expression of the ChM-I gene was regulated positively by a transcription factor, Sp3, and that the binding of Sp3 was regulated by the methylation status in the core-promoter region of the ChM-I gene, especially at one Sp3 binding site. EXPERIMENTAL PROCEDURESTissue Samples-Primary tumor tissues from 24 OS cases were obtained at either biopsy or resection. All were conventional high grade tumors, and histological su...

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Section: Discussionsupporting

confidence: 58%

Methylation in the Core-promoter Region of the Chondromodulin-I Gene Determines the Cell-specific Expression by Regulating the Binding of Transcriptional Activator Sp3

Aoyama

Okamoto

Nagayama

et al. 2004

Journal of Biological Chemistry

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“…P2X 7 mRNA and protein receptor levels are lower in cancer cervical cells than in normal cells, both in culture and in vivo [7,[11][12][13], while CpG sites +211/+212, +330/+331, and +461/+464 were hypermethylated in the cancer cervical cells compared to the normal cells (present data). In other systems, hypermethylation of genes has been associated with repression of tumor suppressor genes [60], and has been implicated in cancer development and metastasis [51,56,61,62]. DNA hypermethylation in the promoter [51] or in 5′ non-coding or coding regions [52,57,58] can lead to defects in DNA repair, cell cycle control, cell adherence, and apoptosis.…”

Section: Discussionmentioning

confidence: 99%

Regulation of P2X7 gene transcription

Zhou

Luo

et al. 2009

Purinergic Signalling

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The pro-apoptotic P2X 7 receptor regulates growth of epithelial cells. The objectives of the study were to understand P2X 7 gene transcription; to identify the active promoter and the transcription initiation site (TpIS); and to begin understanding regulation of P2X 7 gene transcription. Experiments in vitro utilized normal and cancerous cultured human uterine cervical epithelial cells, and HEK293 cells overexpressing P2X 7 -luciferase reporters. Experiments in vivo used surgical specimen of normal and cancerous uterine cervix. Assays involved DNA, RNA, and protein techniques. (a) The P2X 7 TpIS was localized to adenine (+1) at nt 1683 of the human P2X 7 gene [GenBank Y12851]), with a TTAAA sequence at nt −32/−28 and an active promoter region within nt −158/+32. (b) P2X 7 transcription was found to be regulated by two enhancers located at nt + 222/+232 and +401/+573 regions downstream of the active P2X 7 promoter. (c) The putative enhancer regions formed four DNA-protein complexes. (d) P2X 7 transcription was found to be controlled by hypermethylated cytosines at cytosine-phosphodiesterguanosines (CpG) that cluster or co-localize with the enhancers' sites. (e) We identified nine CpGs as inhibitory cis elements, and three CpG sites that are hypermethylated in cultured cervical epithelial cells and in cervix epithelia in vivo. (f) In cancer cervical cells, the degree of hypermethylation of the CpG sites was greater than in the normal cervical cells. Expression of the P2X 7 receptor is controlled by hypermethylated CpGs that flank transcription enhancers located within a 547-nt region downstream of the promoter.

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“…This hypermethylation was confirmed to be associated with a condensed chromatin structure (Villar-Garea and Esteller, 2004). Subsequent experiments have revealed that CpG methylation of the osteocalcin promoter region diminishes during in vitro osteoblastic differentiation of MSCs (Villagra et al, 2002). After differentiation by mechanical stimulus, upregulation of bone-specific genes has been found to be due to reduced CpG methylation of the genes (Arnsdorf et al, 2010;Karakaş et al, 2014).…”

Section: Dna Methylation In Osteogenic Differentiationmentioning

confidence: 96%

Epigenetic regulation of specific transcription factors in osteogenicdifferentiation of mesenchymal stem cells

Heydarabad¹,

Vatanmakanian²,

Nikasa³

et al. 2016

Turk J Biol

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An abundance of experiments have been performed to clarify the differentiation process of mesenchymal stem cells (MSCs). Osteogenic differentiation and in vitro conditions favoring these cell lineages have attracted the attention of many researchers. Moreover, the gene expression profile during MSC differentiation toward its main specialized cells (bone, cartilage, and adipose cells) has been mostly understood. In the last decades another layer of investigation has attempted to clarify the epigenetic mechanisms underlying MSC differentiation into its specialized cells. It has been shown that as MSCs progress through the differentiation process, more nonspecific genes undergo DNA methylation to prevent differentiation into improper cell fates. Moreover, promoters of lineage-specific genes are strongly hypomethylated in MSCs during differentiation. The main objective of this review is to address the role of major epigenetic mechanisms such as DNA methylation, histone modifications, and noncoding RNAs, especially miRNAs, in osteoblastic differentiation of MSCs and to summarize all the previous studies that have determined the epigenetic alterations of the nuclear genome during osteoblastic differentiation of MSCs.

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Reduced CpG methylation is associated with transcriptional activation of the bone‐specific rat osteocalcin gene in osteoblasts*

Cited by 95 publications

References 32 publications

Methylation in the Core-promoter Region of the Chondromodulin-I Gene Determines the Cell-specific Expression by Regulating the Binding of Transcriptional Activator Sp3

Methylation in the Core-promoter Region of the Chondromodulin-I Gene Determines the Cell-specific Expression by Regulating the Binding of Transcriptional Activator Sp3

Regulation of P2X7 gene transcription

Epigenetic regulation of specific transcription factors in osteogenicdifferentiation of mesenchymal stem cells

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