Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transforming growth factor (TGF)-beta superfamily members and their receptors play a part in the differentiation of pulp cells into odontoblasts during reparative dentinogenesis. Bovine primary pulp-cell culture has been used as an in vitro model for proliferation and differentiation of pulp cells into preodontoblasts. To explore the molecular cascade of odontoblast differentiation, Northern blot analyses and reverse transcriptase polymerase chain reaction were here used to investigate the expression patterns of the genes for TGF-beta superfamily members: TGF-beta 1, namely bone morphogenetic protein (BMP)-4, BMP-7, activin-beta A and activin-beta B, and their type I and type II receptors, namely activin receptor-like kinase (ALK)-2 (ActR-I), ALK-3 (BMPR-IA), ALK-4 (ActR-IB), ALK-5 (T beta R-I), BMPR-II and T beta R-II, during differentiation of pulp cells into preodontoblasts in bovine adult pulp-cell culture. TGF-beta 1 and BMP-4 mRNAs were expressed from day 14 when matrix formation increased. BMP-7 mRNA was expressed only on day 28 when osteocalcin appeared. ALK-2 mRNA was increased from the beginning of the culture. ALK-3 and ALK-5 mRNAs first decreased on day 14 and increased again on day 21. T beta R-II and BMPR-II mRNAs were almost constant. These results suggest that the differentiation of pulp cells into preodontoblasts may be regulated by changes in the temporally coordinated expression pattern of TGF-beta superfamily members and their receptors, including up-regulation of transcription of TGF-beta 1, BMP-4, BMP-7, ALK-2, ALK-3, and ALK-5.
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PMID:Temporal changes in expression of transforming growth factor-beta superfamily members and their receptors during bovine preodontoblast differentiation in vitro. 929 67

Cbfa1 is an essential transcription factor for osteoblast differentiation and bone formation. We investigated functional differences among three isoforms of Cbfa1: Type I (originally reported as Pebp2alphaA by Ogawa et al. (Ogawa, E., Maruyama, M., Kagoshima, H., Inuzuka, M., Lu, J., Satake, M., Shigesada, K., and Ito, Y. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 6859-6863), Type II (originally reported as til-1 by Stewart et al. (Stewart, M., Terry, A., Hu, M., O'Hara, M., Blyth, K., Baxter, E., Cameron, E., Onions, D. E., and Neil, J. C. (1997) Proc. Natl. Acad. Sci. U. S. A. 94, 8646-8651), and Type III (originally reported as Osf2/Cbfa1 by Ducy et al. (Ducy, P., Zhang, R., Geoffroy, V., Ridall, A. L., and Karsenty, G. (1997) Cell 89, 747-754). A reverse transcriptase-polymerase chain reaction analysis demonstrated that these isoforms were expressed in adult mouse bones. The transient transfection of Type I or Type II Cbfa1 in a mouse fibroblastic cell line, C3H10T1/2, induced the expression of alkaline phosphatase (ALP) activity. This induction was synergistically enhanced by the co-introduction of Xenopus BMP-4 cDNA. In contrast, the transient transfection of Type III cDNA induced no ALP activity. In C3H10T1/2 cells stably transfected with each isoform of Cbfa1, the gene expression of ALP was also strongly induced in cells transfected with Type I and Type II Cbfa1 but not in cells with Type III Cbfa1. Osteocalcin, osteopontin,and type I collagen gene expressions were induced or up-regulated in all of the cells stably transfected with each isoform of Cbfa1, and Type II transfected cells exhibited the highest expression level of osteocalcin gene. A luciferase reporter gene assay using a 6XOSE2-SV40 promoter (6 tandem binding elements for Cbfa1 ligated in front of the SV40 promoter sequence), a mouse osteocalcin promoter, and a mouse osteopontin promoter revealed the differences in the transcriptional induction of target genes by each Cbfa1 isoform with or without its beta-subunit. These results suggest that all three of the Cbfa1 isoforms used in the present study are involved in the stimulatory action of osteoblast differentiation, but they exert different functions in the process of osteoblast differentiation.
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PMID:Cbfa1 isoforms exert functional differences in osteoblast differentiation. 1006 51

Similarities between primitive neuroectodermal tumors and central nervous system (CNS) progenitor cells have evoked interest in the response of these tumors to endogenous growth factors. The bone morphogenetic proteins (BMPs) have recently been found to regulate survival and differentiation of CNS progenitor cell populations. In this study, we investigated the effects of BMP-2, BMP-4, and BMP-6 on the undifferentiated cerebellar primitive neuroectodermal tumor or medulloblastoma cell line DAOY. Analysis by reverse transcriptase-polymerase chain reaction showed that mRNAs for type IA and type II BMP receptors were present in control cultures. In cultures treated with BMP-2, mRNAs for BMP receptor type IB and the activin R-I receptor became evident. Cultures were analyzed for total cell counts, proliferating cell nuclear antigen (PCNA), and apoptotic DNA fragmentation. There was a significant increase in total cell number in the BMP-2 and BMP-4 treatment groups, without any change in PCNA reactivity, and a dramatic decrease in the proportion of apoptotic nuclei at concentrations of BMP-2 and BMP-4 above 5 ng/ml (P<0.001). These effects were not observed with BMP-6, TGF-beta1 or GDNF. These results suggest that the increase in total cell number is due to the attenuation of apoptosis by BMP-2 and BMP-4. The anti-apoptotic effect of BMP-2 and BMP-4 on this neuroectodermal cell line has potential clinical implications for neuroectodermal tumors.
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PMID:Bone morphogenetic proteins-2 and -4 attenuate apoptosis in a cerebellar primitive neuroectodermal tumor cell line. 1033 54

Expressions of mRNAs for four subtilisin-like proprotein convertases (SPCs: furin, PACE4, PC6, and PC8) and bone morphogenetic protein 4 (BMP4) in the rat molar tooth during development were analyzed by Northern blotting, reverse transcriptase-polymerase chain reaction (RT-PCR), and in situ hybridization to explore the possible involvement of SPCs in the processing of proBMPs. We found a temporospacial expression of PACE4, but not one of the other SPCs, in this tissue; i.e., RT-PCR analysis revealed that the level of PACE4 mRNA, but not that of the other SPC mRNAs became high around the second postnatal day. This increase was in good accordance with the increase in BMP4 mRNA, indicating an apparent association of these molecules with the differentiation and establishment of functional ameloblasts and odontoblasts. During dentinogenesis, PACE4 mRNA was localized in the ameloblasts and odontoblasts. These observations suggest that PACE4 plays a crucial role in dentinogenesis, especially via the activation of BMPs.
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PMID:Highly regulated expression of subtilisin-like proprotein convertase PACE4 (SPC4) during dentinogenesis. 1083 28

A cell culture system consisting of mouse S17 stromal cells supplemented with cytokines was developed for hematopoietic differentiation of rhesus monkey embryonic stem (ES) cells. The differentiated colonies that formed contained clusters of hematopoietic-like cells, as well as structures similar in appearance to embryonic blood islands. When this culture system was supplemented with bone morphogenetic protein 4 (BMP-4), the numbers of primary hematopoietic clusters increased by an average of 15 fold. The primary hematopoietic clusters containing clonogenic precursors (expandable hematopoietic clusters) increased by 18 fold. Immunofluorescence analysis showed that a substantial percentage of the hematopoietic-like cells were CD34(+), with morphologic features of undifferentiated blast cells. Enrichment of the CD34(+) cells was associated with enhanced stromal-dependent, cytokine-driven formation of cobblestone colonies on secondary plating. The hematopoietic identity of the precursors was further indicated by their expression of genes associated with hematopoietic differentiation, as well as morphologic assessments that showed erythroid and myeloid lineages among the progeny cells. In addition, reverse transcriptase-polymerase chain reaction analysis of BMP-4-treated rhesus monkey ES cells demonstrated an up-regulation of early-expressed genes responsible for embryonic hematopoiesis and angiogenesis during the first 7 days of culture. These observations suggest that embryonic mesoderm regulatory protein may mimic physiologic signals that are required for the onset of embryonic hematopoiesis and stem cell formation in rhesus monkey ES cells.
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PMID:Bone morphogenetic protein 4 induces efficient hematopoietic differentiation of rhesus monkey embryonic stem cells in vitro. 1143 1

The expression of hard tissue associated proteins may be used to identify periodontal fibroblasts with the capability to facilitate periodontal regeneration. The aim of this study was to describe, by immunohistochemistry, the distribution of osteocalcin, osteopontin, bone sialoprotein and bone morphogenic proteins-2 and -4 (BMP-2 and BMP-4) within the human periodontium. Furthermore, the expression of mRNA for the above proteins and alkaline phosphatase by gingival and periodontal ligament fibroblasts in vitro was also assessed by reverse transcriptase polymerase chain reaction (RT-PCR). Localization of osteopontin, osteocalcin, BMP-2 and BM P-4 within sections of human periodontal structures was stronger in the periodontal ligament compared to the gingiva. Bone sialoprotein was not detected in either of the soft tissues but, along with osteopontin and osteocalcin, it was localized in the cementum and bone. In vitro, both the gingival and periodontal ligament fibroblasts expressed mRNA for alkaline phosphatase, BMP-2, BMP-4 and osteopontin. Although there were no differences in the expression of alkaline phosphatase and BMP-4 mRNA between the two cell types, we noted significantly higher mRNA levels of osteopontin in the periodontal ligament and BM P-2 in the gingival fibroblasts. Osteocalcin and bone sialoprotein mRNA expression was only noted in the cultured periodontal ligament fibroblasts. From these results, it can be concluded that distinct differences exist between the two fibroblast populations in terms of the localization and mRNA expression of the majority of the hard tissue associated proteins. Furthermore, the elevated in vitro mRNA expression for osteocalcin, osteopontin and bone sialoprotein may be used to identify cells with the potential to facilitate hard tissue formation and hence periodontal regeneration.
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PMID:Expression of bone associated macromolecules by gingival and periodontal ligament fibroblasts. 1145 11

The Xenopus tropicalis BMP-2 and BMP-4 genes have been cloned and sequenced. A comparison with the corresponding genes from X. laevis reveals that the BMP-4 genes are conserved at a higher extent than the BMP-2 genes. This is especially evident for the intron sequences, but is also reflected by the exon sequences. While the amino acids of X. tropicalis and X. laevis BMP-4 proteins diverge at about 4%, those of BMP-2 proteins diverge at about 7%. By reverse transcriptase polymerase chain reaction analyses and whole mount in situ hybridizations, we demonstrate the temporal and spatial expression patterns of X. tropicalis BMP-2 and BMP-4 genes. BMP-2 is found to be expressed maternally, and later in development, in migrating heart progenitor cells as well as in the final heart, within the pineal gland and the olfactory placodes. BMP-4 is zygotically activated within the ventral marginal zone and later found in the eye, the otic vesicle, the heart and within blood islands. Although the overall patterns are very similar to those found in X. laevis, there is some distinct difference which might result from the accelerated development in X. tropicalis.
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PMID:Structure and expression of Xenopus tropicalis BMP-2 and BMP-4 genes. 1167 55

Members of the Xvent-2 homeodomain transcription factor family are immediate response genes of BMP-4 signaling. The bone morphogenetic protein response element (BRE) of Xvent-2B was previously identified and characterized with respect to Smad1 and Smad4 binding sites. In this study, we further report on the transcriptional regulation of Xvent-2B. We provide evidence that Xvent-2B (Xvent-2) maintains its own expression through autoregulation. This activity was demonstrated for the endogenous gene by reverse transcriptase-PCR analysis and was found to be insensitive to cycloheximide. Localized by DNase I footprinting were several Xvent-2 binding sites within the proximal upstream region including the BRE. In the early Xenopus embryo, the BRE was shown to be sufficient to drive expression of a green fluorescent protein reporter in a similar pattern compared with the endogenous gene. Furthermore, Xvent-2B was able to activate the BRE in luciferase reporter assays, and in co-injection experiments Xvent-2B and Smad1 were found to synergistically activate the BRE. Moreover, glutathione S-transferase pull-down experiments demonstrated that Xvent-2B directly and specifically interacts with Smad1. This association was mediated by the MH1 domain of Smad1 and required the C-terminal domain of Xvent-2. The failure of an Xvent-2 mutant lacking the C terminus to stimulate the BRE underlines the significance of the C-terminal domain in the described autoregulatory loop.
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PMID:Autoregulation of Xvent-2B; direct interaction and functional cooperation of Xvent-2 and Smad1. 1170 65

We have performed a high-capacity, semiquantitative, reverse transcriptase-polymerase chain reaction screen for expression of fibroblast growth factor (FGF) and transforming growth factor beta (TGFbeta) family genes as well as their cognate receptors. By using cDNA prepared from embryonic day 12 to postnatal day 0 embryonic mouse pancreas, we have identified several factors potentially involved in the development of the endocrine pancreas. We find high-level early expression of TGFbeta-1 and -2, and constitutive expression of TGFbeta-3 and their receptors. Of the Inhibin/Activin members, we found exclusively Inhibin-alpha and Activin-betaB to be expressed, and the BMP family was represented by BMP4, BMP5, and BMP7. The predominant forms of the BMP and Activin type II receptors were ActR-IIB and BMPR-II and of the type I receptors, BMPR-1A and -1B were the highest expressed. FGF1, FGF7, FGF9, FGF10, FGF11, and FGF18 were also expressed in the pancreas at varying time points and levels, as well as FGF receptor forms FGFR1b, FGFR1c, FGFR2b, FGFR2c, FGFR3b, and FGFR4. To gain insight into the biological function, we misexpressed members of these families in the pancreas by using the early pancreas promoter Pdx1. Misexpression of FGF4 results in disruption of the pancreas morphology with epithelial structures interspersed in stroma tissue. The endocrine compartment was reduced to scattered single cells, and the exocrine consisted of unbranched ductal epithelia with acinar structures budding off. In contrast, misexpression of BMP-6 resulted in complete agenesis of the pancreas and reduced the size of the stomach and spleen dramatically and caused fusion of the liver and duodenum.
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PMID:Expression and misexpression of members of the FGF and TGFbeta families of growth factors in the developing mouse pancreas. 1266 4

Linuron is an herbicide with weak androgen receptor (AR) antagonist activity. Exposure to linuron from gestation days (GD) 12 to 21 perturbs androgen-dependent male reproductive development. In utero exposure to 50-mg/kg/day linuron induces malformations of the epididymis and the vas deferens. The objective of this study was to identify alterations in gene expression within the testis and epididymis associated with abnormal Wolffian duct development and to correlate changes in gene expression with the gross morphology of the affected epididymides. Pregnant Sprague-Dawley rats were administered either corn oil vehicle or linuron (50 mg/kg/day) by gavage from GD 12 to 21 (n = 3-6 controls, n = 5-10 linuron-treated dams per time point). Changes in gene expression were evaluated in testes on GD 21 and in epididymides on GD 21 and postnatal day (PND) 7, using cDNA microarrays and confirmed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) analyses. RNA was isolated from intact epididymides with reduced or no ductal coiling from the linuron groups, and epididymides with noncontiguous ducts were excluded. In the fetal testis, exposure to linuron did not result in reduced mRNA expression of the AR or that of several steroidogenic enzymes, supporting the hypothesis that linuron does not reduce fetal testosterone production. Linuron induced a significant decrease in AR mRNA expression in GD 21 epididymides. Significant changes in mRNA expression in GD 21 and PND 7 epididymides were also identified in the epidermal growth factor (EGF), insulin-like growth factor 1 (IGF-1), bone morphogenetic protein (BMP), fibroblast growth factor (FGF), and Notch signaling pathways. These pathways are involved in tissue morphogenesis. Changes in the expression of AR and IGF-1 receptors were detected by immunostaining in malformed epididymides from linuron-exposed rats. Linuron induced changes in epididymal gene expression suggestive of altered paracrine interactions between the mesenchyme and epithelial cells during development. The EGF, Notch, IGF-1, BMP4, and FGF signaling pathways may be involved in normal testosterone-mediated development of the Wolffian duct.
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PMID:Altered gene expression during rat Wolffian duct development in response to in utero exposure to the antiandrogen linuron. 1273 Jun 24


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