Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have identified and purified to near homogeneity two specific single-stranded DNA-binding factors (SPSF I and II) with molecular masses of 42 and 39 kDa, respectively, from calf thymus. Gel retention analysis and competition experiments demonstrate that the ubiquitous proteins SPSF I and II specifically interact with single-stranded DNA derived from the minimal in vitro origin of replication of bovine papillomavirus type 1 and a region of the viral genome proposed to be involved in plasmid maintenance. Bovine papillomavirus type 1 proteins do not interfere with DNA binding of SPSF I and II. The exact location of the binding domains of SPSF I and II on the DNA has been determined by methylation interference and T4 DNA polymerase footprinting. A potential cellular binding site for SPSF I and II is the major promoter (P2) of the human c-myc gene.
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PMID:Two cellular single-strand-specific DNA-binding proteins interact with two regions of the bovine papillomavirus type 1 genome, including the origin of DNA replication. 132 53

We have used the antisense strategy to study the role of certain genes in cell cycle progression. In particular, we used antisense oligodeoxynucleotides to study: (1) the role of the IGF-1 receptor in the control of cell proliferation; and (2) the sequence of gene expression during the cell cycle. Our results can be summarized as follows: (1) the activation of the IGF-1 receptor by its ligand, IGF-1, is an obligatory step in the proliferation of fibroblasts and hemopoietic cells; and (2) the expression of DNA synthesis genes, such as PCNA, DNA polymerase alpha, and cdc2, is dependent on the expression of previous genes. A tentative temporal order is: c-myc > c-myb > IGF-1 receptor > DNA synthesis genes.
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PMID:Inhibition of cell cycle progression by antisense oligodeoxynucleotides. 134 Jan 57

G1-specific temperature-sensitive (ts) mutants of the cell cycle arrest in G1 after serum stimulation at the restrictive temperature. Under these conditions, the RNA levels of late growth-regulated genes (such as DNA polymerase alpha, PCNA, thymidine kinase, and core histones) are markedly decreased or even undetectable, while early growth-regulated genes (for instance, c-myc) are normally expressed, and certain promoters are actually super-induced. We have used the human PCNA gene transfected into TK-ts13 cells (a G1-specific ts mutant) to investigate whether the inhibition of gene expression caused by this type of growth inhibition occurs at a transcriptional or post-transcriptional level. Constructs were made in which the 5' and 3' flanking sequences of the human PCNA gene were replaced by the corresponding elements of the SV40 T antigen coding gene. Using these constructs and data from run-on assays and RT-PCR, we conclude that the failure of expression of the PCNA gene in G1-arrested TK-ts13 cells occurs at the transcriptional level.
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PMID:The role of the promoter in the expression of the PCNA gene. 136 Feb 87

Investigations of mast cell biology have often used immortalized cultured cells which are continuously proliferating. In vivo, however, only 2% or fewer tissue mast cells are actively dividing. We used aphidicolin, an inhibitor of DNA polymerase to induce a proliferative arrest of murine mast cells characterized by an inhibition of cell division and thymidine incorporation, with accumulation of cells in G1 and early S phase of the cell cycle. Uridine incorporation and cell viability were not significantly impaired. DNA synthesis and cell division both resumed rapidly upon removal of the drug. Morphometric analysis demonstrated that cell size, granule size, and number of granules per cell were all increased in aphidicolin-treated cells. Proliferative arrest also produced a 14-fold increase in cellular histamine content, but did not alter the proteoglycans synthesized by the cell. The level of c-myc mRNA was reduced in aphidicolin-arrested cells, but returned to the level observed in untreated cells within 1 hr of removal of the drug. In contrast, the constitutive steady-state RNA levels of tumour necrosis factor-alpha (TNF-alpha), B2-microglobulin, actin, and the c-Ha-ras and c-fes protooncogenes were not altered. Aphidicolin-induced proliferative arrest did not prevent the induction of TNF-alpha, interleukin-6 (IL-6) and c-fos genes in response to calcium ionophore. Both the magnitude and induction kinetics of these messages were similar in aphidicolin-treated and untreated cells. We conclude that proliferative arrest results in morphological and biochemical changes suggestive of cellular maturation, but inhibition of cell division alone is not sufficient to alter mast cell phenotype. Although optimal c-myc expression appears to require active proliferation, cytokine gene induction can occur in non-dividing cells. These data suggest that the proliferative quiescence of in vivo mast cells should not preclude their involvement in biological events via elaboration of multi-functional cytokines.
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PMID:Aphidicolin-induced proliferative arrest of murine mast cells: morphological and biochemical changes are not accompanied by alterations in cytokine gene induction. 138 41

Oncoprotein c-myc is expressed in proliferating but not quiescent mammalian cells, and its overexpression or inappropriate expression is associated with malignant transformation. However, in spite of an intense interest, the normal function of this protein has remained elusive. As a step towards the elucidation of the function of c-myc protein, we studied its distribution within several types of cells, including HL 60, K 562, COLO 320, and CHEF/18 cells. In all of the cells studied, c-myc protein was detected in high molecular weight protein fractions, in 350-600 Kd range, in gel-exclusion chromatography and sucrose gradient centrifugation. This distribution of c-myc protein coincided with the distribution of DNA polymerase alpha and several other enzymes necessary for DNA replication. The data suggest that c-myc product may be a component of the replitase complex of enzymes involved in nuclear DNA replication.
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PMID:Association of c-myc protein with enzymes of DNA replication in high molecular weight fractions from mammalian cells. 164 64

The c-fos gene product Fos has been implicated in many cellular processes, including signal transduction, DNA synthesis, and resistance to antineoplastic agents. A fos ribozyme (catalytic RNA) was designed to evaluate the effects of suppressing Fos protein synthesis on expression of enzymes involved in DNA synthesis, DNA repair, and drug resistance. DNA encoding the fos ribozyme (fosRb) was cloned into the pMAMneo expression plasmid, and the resultant vector was transfected into A2780DDP cells resistant to the chemotherapeutic agent cisplatin. The parental drug-sensitive A2780S cells were transfected with the pMMV vector containing the c-fos gene. Morphological alterations were accompanied by significant changes in pharmacological sensitivity in both c-fos- and fosRb-transfected cells. pMAMneo fosRb transfectants revealed decreased c-fos gene expression, concomitant with reduced thymidylate (dTMP) synthase, DNA polymerase beta, topoisomerase I, and metallothionein IIA mRNAs. In contrast, c-myc expression was elevated after fos ribozyme action. Insertion of a mutant ribozyme, mainly capable of antisense activity, into A2780DDP cells resulted in smaller reductions in c-fos gene expression and in cisplatin resistance than the active ribozyme. These studies establish a role for c-fos in drug resistance and in mediating DNA synthesis and repair processes by modulating expression of genes such as dTMP synthase, DNA polymerase beta, and topoisomerase I. These studies also suggest the utility of ribozymes in the analysis of cellular gene expression.
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PMID:Ribozyme-mediated cleavage of c-fos mRNA reduces gene expression of DNA synthesis enzymes and metallothionein. 166 Jan 42

Different portions of the 5'-upstream region of the mouse DNA polymerase beta gene were combined with bacterial chloramphenicol acetyltransferase (CAT) gene of the CAT vector. Transfection of these recombinant plasmids into mouse NIH/3T3 cells has revealed that each of the previously identified two negatively acting regions (silencers I and II) of this gene consists of multiple sub-domains. The distal silencer (silencer I) at around -1.5 kb consists of four sub-domains (-1852 to -1667, -1663 to -1616, -1564 to -1525 and -1355 to -1257). The promoter-proximal silencer (silencer II) at around -0.5 kb consists of two functional domains (-681 to -523 and -490 to -447) separated by a neutral region of 33 base pairs. Silencer II functioned efficiently when silencer I was deleted. Conversely, the distal silencer I functioned efficiently when silencer II was deleted. Thus, these silencers functioned redundantly to each other in NIH/3T3 cells. Nucleotide sequence analysis revealed no extensive sequence similarity between these two silencers. Significant sequence similarity is present between a distal portion of silencer II and the c-myc gene silencer, and also between a proximal portion of silencer II and the mouse F9 cell-specific silencer. A protein factor(s) that specifically bound to the silencer elements was detected in nuclear extracts of NIH/3T3 cells and mouse liver in which DNA polymerase beta was expressed at a rather low level. The same binding factor(s) can bind to both silencer I and II regions, although its affinity for silencer II is much higher than that for silencer I.
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PMID:Organization of mouse DNA polymerase beta gene silencer elements and identification of the silencer-binding factor(s). 190 Feb 71

The autocrine, paracrine, or systemic growth factors responsible for fetal lung cell growth are not completely defined. The progression-type insulin-like growth factors and epidermal growth factor, or transforming growth factor-alpha acting through the epidermal growth factor receptor, appear to act on the developing lung epithelium. The competence factors that facilitate the actions of progression factors during lung growth are unknown. Fetal rat lung cells in vitro synthesize a platelet-derived growth factor (PDGF)-like polypeptide, which we have hypothesized may play a paracrine role in normal lung development. Slot blot and Northern blot analyses of fetal rat lung mRNA have been used to determine if there is a relationship between expression of message for PDGF-A or PDGF-B chains, or their cognate receptors, and periods of maximal growth during late fetal rat lung development. Whole lung mRNA was extracted on 18, 19, 20, 21, and 22 days of gestation (term = 22 days). The peak of DNA synthesis, as assessed by expression of message for DNA polymerase alpha, histone 3, and the proto-oncogenes c-fos and c-myc, which are stimulated by binding of growth factors including PDGF, occurred during the canalicular stage of lung development on days 19 and 20 of gestation. Expression of message for PDGF-A and PDGF-B chains was low during the pseudoglandular stage on day 18, peaked during the canalicular stage on days 19 and 20, then fell again during the saccular stage at days 21 and 22 of gestation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Platelet-derived growth factor and growth-related genes in rat lung. I. Developmental expression. 191 Aug 22

Peritoneal cells were derived from a patient (PK) with adenocarcinoma of the colon during the course of cisplatin/5-fluorouracil (5-FUra) treatment. Resistance to cisplatin and 5-FUra, characterized by a lack of response to chemotherapy and continued growth of the tumor, was concomitantly associated with a 2-4-fold increase in DNA copy number for dTMP synthase and dihydrofolate reductase. There was a corresponding amplification in DNA copy number of the c-myc (2X), H-ras (4X), and c-fos (15X) oncogenes. Cytogenetic studies revealed an iso (13q) chromosome, but failed to show any double minutes or homogeneously staining regions. In addition, drug-resistant tumor cells from PK and another patient (HG) displayed enhanced expression of dTMP synthase, c-fos and DNA polymerase beta when compared to normal colon tissue and the HCT8 human colon carcinoma cell line. These results suggest that elevated oncogene DNA and gene expression may be involved in the development of cisplatin resistance.
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PMID:Differential oncogene amplification in tumor cells from a patient treated with cisplatin and 5-fluorouracil. 214 97

Several nuclear and surface proteins are expressed in varying amounts in the different phases of the cell cycle. For some of them the coding gene is not known and changes in their expression could simply be secondary to changes in the proliferative activity of the population. Other proteins are oncogene products, probably having a direct regulatory function in cell proliferation, differentiation and malignant transformation. Studying these proteins may both permit a better understanding of the mechanisms regulating proliferation and differentiation and provide kinetic parameters for describing the cell cycle. Based on antibodies against these proteins, bivariate flow cytometry (FCM) is able to quantitate their expression simultaneously with DNA distribution. This allows protein expression to be related precisely with each cell cycle phase in populations having different proliferative activity. Further advantages of bivariate FCM are that few cells are required for the analysis and the percentage of cells expressing the (onco) gene product can be determined. Several cellular proteins have been investigated with bivariate FCM, and the data are reviewed. Some proteins not coded by oncogenes (such as cyclin, the Ki-67 reactive antigen and DNA polymerase alpha) are expressed in cycling, but not in G0 cells and are of special interest for the kineticist, since they could identify cells which are able to initiate DNA synthesis, i.e. those representing the "growth fraction" of the population. Statin, on the contrary, is apparently expressed only in G0 cells. The expression of some proteins coded by oncogenes, such as p53 and the c-myc product is high in proliferating G1 cells and decreases with differentiation. The expression of the c-ras product is not strictly related to cell cycle phases and increases with differentiation. Technical improvements (allowing, for example, the monitoring of the changes in protein expression following the microinjection of a protein-blocking substance into the cells and the inclusion of phenotype markers into the analysis) will expand the role of bivariate FCM for these research works.
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PMID:Cell cycle-related proteins and flow cytometry. 214 99


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