Abstract:
:Pretreatment of 3T6 murine cells with the carcinogen UV radiation or N-acetoxy-N-acetylaminofluorene increased the number of methotrexate-resistant colonies. This carcinogen-induced enhancement was seen only at low toxicities. The enhancement was transient and was observed at its maximum when cells were subjected to methotrexate selection 12 to 24 h after treatment. The addition of a tumor-promoting agent, 12-O-tetradecanoylphorbol-13-acetate, during or after carcinogen treatment further enhanced this effect. A large proportion of the resistant colonies had an increase in the dihydrofolate reductase gene copy number and the relative proportions of colonies with amplified genes were similar, regardless of whether selected cells were untreated, treated with carcinogen, or treated with carcinogen plus promoter. We discuss some of the variables which both enhance the generation and improve the detection of methotrexate-resistant colonies, as well as certain implications of our results for the generation and mechanism of gene amplification.
journal_name
Mol Cell Bioljournal_title
Molecular and cellular biologyauthors
Tlsty TD,Brown PC,Schimke RTdoi
10.1128/mcb.4.6.1050subject
Has Abstractpub_date
1984-06-01 00:00:00pages
1050-6issue
6eissn
0270-7306issn
1098-5549journal_volume
4pub_type
杂志文章abstract::Nonsense-mediated mRNA decay (NMD) is a conserved proofreading mechanism that protects eukaryotic cells from the potentially deleterious effects of truncated proteins. Studies of Saccharomyces cerevisiae imply that NMD is a predominantly cytoplasmic decay pathway, while studies of mammalian systems suggest that decay ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.23.3.842-851.2003
更新日期:2003-02-01 00:00:00
abstract::We characterized the organization and expression of PHO5 and PHO3, the tightly linked repressible and constitutive acid phosphatase genes of Saccharomyces cerevisiae. The "constitutive" gene, PHO3, is expressed only when PHO5 is not. Altering PHO5 expression, either through promoter deletions or through mutations in t...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.6.6.1855
更新日期:1986-06-01 00:00:00
abstract::Simultaneous resistance to an array of drugs with different cytotoxic activities is a property of Saccharomyces cerevisiae, in which the protein Pdr3p has recently been shown to play a role as a transcriptional regulator. We provide evidence that the yeast PDR3 gene, which encodes a zinc finger transcription factor im...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.15.8.4043
更新日期:1995-08-01 00:00:00
abstract::Considering the link between plasma high-density lipoprotein (HDL) cholesterol levels and a protective effect against coronary artery disease as well as the suggested beneficial effects of retinoids on the production of the major HDL apolipoprotein (apo), apo A-I, the goal of this study was to analyze the influence of...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.16.7.3350
更新日期:1996-07-01 00:00:00
abstract::Using chromatin immunoprecipitation assays, we studied the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated recruitment of the aryl hydrocarbon receptor (AhR) and several co-regulators to the CYP1A1 promoter. AhR displayed a time-dependent recruitment, reaching a peak at 75 min and maintaining promoter occupancy fo...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.25.13.5317-5328.2005
更新日期:2005-07-01 00:00:00
abstract::Although the primary function of U1 snRNA is to define the 5' donor site of an intron, it can also block the accumulation of a specific RNA transcript when it binds to a donor sequence within its terminal exon. This work was initiated to investigate if this property of U1 snRNA could be exploited as an effective metho...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.21.8.2815-2825.2001
更新日期:2001-04-01 00:00:00
abstract::Secretory proteins in eukaryotic cells are transported to the cell surface via the endoplasmic reticulum (ER) and the Golgi apparatus by membrane-bounded vesicles. We screened a collection of temperature-sensitive mutants of Saccharomyces cerevisiae for defects in ER-to-Golgi transport. Two of the genes identified in ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.18.12.7139
更新日期:1998-12-01 00:00:00
abstract::Saccharomyces cerevisiae dbf4 and cdc7 cell cycle mutants block initiation of DNA synthesis (i.e., are iDS mutants) at 37 degrees C and arrest the cell cycle with a 1C DNA content. Surprisingly, certain dbf4 and cdc7 strains divide their chromatin at 37 degrees C. We found that the activation of the Cdc28 mitotic prot...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.15.10.5312
更新日期:1995-10-01 00:00:00
abstract::Plasmid DNA substrates were X-irradiated and injected into the nuclei of Xenopus laevis oocytes. After incubation for 20 h, DNA was recovered from the oocytes and analyzed simultaneously for repair and for intermolecular homologous recombination by electrophoresis and bacterial transformation. Oocyte-mediated repair o...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.10.11.5849
更新日期:1990-11-01 00:00:00
abstract::The NF-kappa B/Rel family of transcription factors participates in the control of a wide array of genes, including genes involved in embryonic development and regulation of immune, inflammation, and stress responses. In most cells, inhibitory I kappa B proteins sequester NF-kappa B/Rel in the cytoplasm. Cellular stimu...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.23.4.1418-1427.2003
更新日期:2003-02-01 00:00:00
abstract::We have previously shown that Saccharomyces cerevisiae Isw2 complex slides nucleosomes to remodel chromatin in vivo. Our data suggested a model in which Isw2 complex binds the histone octamer and DNA separately to generate the force necessary for nucleosome movement. Here we find that the histone H4 "basic patch" is t...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.25.21.9165-9174.2005
更新日期:2005-11-01 00:00:00
abstract::Three ras homologs have been identified in Drosophila melanogaster. Here we describe the tissue distribution of their transcripts as analyzed by in situ hybridization. The RNAs of the three genes show a similar distribution at every developmental stage examined. In embryos, the transcripts are uniformly distributed. I...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.6.6.2241
更新日期:1986-06-01 00:00:00
abstract::The natriuretic peptide receptors are three homologous cell surface proteins, each with a single transmembrane domain. The atrial natriuretic peptide receptor type A (ANPRA) and the homologous receptor type B (ANPRB) are both membrane guanylyl cyclases that synthesize cyclic GMP as an intracellular second messenger. T...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.11.7.3454
更新日期:1991-07-01 00:00:00
abstract::The Saccharomyces cerevisiae cell cycle is arrested in G1 phase by the mating factor pathway. Genetic evidence has suggested that the G1 cyclins Cln1, Cln2, and Cln3 are targets of this pathway whose inhibition results in G1 arrest. Inhibition of Cln1- and Cln2-associated kinase activity by the mating factor pathway a...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.18.1.433
更新日期:1998-01-01 00:00:00
abstract::The transcriptional regulating protein of 132 kDa (TReP-132) has been identified in steroidogenic tissues, where it acts as a coactivator of steroidogenic factor 1 (SF-1). We show here that TReP-132 plays a role in the control of cell proliferation. In human HeLa cells, TReP-132 knockdown by using small interfering RN...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.25.11.4335-4348.2005
更新日期:2005-06-01 00:00:00
abstract::Mammalian GRP78/BiP is a stress-inducible 78-kDa endoplasmic reticulum (ER) protein with molecular chaperone and calcium-binding properties. The transactivation of grp78 by the calcium ionophore A23187 provides a model system with which to study the signal transduction that allows mammalian cells to sense calcium depl...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.15.4.2263
更新日期:1995-04-01 00:00:00
abstract::The protein kinase inhibitor 2-aminopurine (2-AP) greatly stimulated expression in human promonocytes-macrophages of plasmid constructs carrying various reporter genes (chloramphenicol acetyltransferase, lacZ, firefly luciferase [luc], and Salmonella typhimurium histidinol dehydrogenase [his]) driven by the human immu...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.13.9.5245
更新日期:1993-09-01 00:00:00
abstract::The Integrator Complex is a group of proteins responsible for the endonucleolytic cleavage of primary small nuclear RNA (snRNA) transcripts within the nucleus. Integrator subunits 9 and 11 (IntS9/11) are thought to contain the catalytic activity based on their high sequence similarity to CPSF100 and CPSF73, which have...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.06511-11
更新日期:2012-03-01 00:00:00
abstract::In response to ionizing radiation (IR), the tumor suppressor p53 is stabilized and promotes either cell cycle arrest or apoptosis. Chk2 activated by IR contributes to this stabilization, possibly by direct phosphorylation. Like p53, Chk2 is mutated in patients with Li-Fraumeni syndrome. Since the ataxia telangiectasia...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.22.18.6521-6532.2002
更新日期:2002-09-01 00:00:00
abstract::Entry into mitosis is controlled by the cyclin-dependent kinase CDK1 and can be delayed in response to DNA damage. In some systems, such G(2)/M arrest has been shown to reflect the stabilization of inhibitory phosphorylation sites on CDK1. In human cells, full G(2) arrest appears to involve additional mechanisms. We d...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.20.7.2358-2366.2000
更新日期:2000-04-01 00:00:00
abstract::The ∼230-residue C-terminal tail of the epidermal growth factor receptor (EGFR) is phosphorylated upon activation. We examined whether this phosphorylation is affected by deletions within the tail and whether the two tails in the asymmetric active EGFR dimer are phosphorylated differently. We monitored autophosphoryla...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.00248-15
更新日期:2015-09-01 00:00:00
abstract::Selective and accurate transcription of purified genes by RNA polymerase II requires multiple factors. The factor designated TFIID was purified extensively from HeLa cell nuclear extracts by using a simple and novel complementation assay. Thus, TFIID was preferentially inactivated by mild heat treatment of a nuclear e...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.8.10.4028
更新日期:1988-10-01 00:00:00
abstract::Using an expression cloning assay, we have isolated a novel cDNA, referred to as rsp-1, which suppresses the v-Ras-transformed phenotype. When introduced into NIH 3T3 fibroblasts under the control of a metallothionein promoter, rsp-1 confers resistance to v-Ras, but not to v-Mos or v-Src, and inhibits growth of the ce...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.12.9.3750
更新日期:1992-09-01 00:00:00
abstract::A cDNA encoding a novel Krüppel-type zinc finger protein, FKLF, was cloned from fetal globin-expressing human fetal erythroid cells. The deduced polypeptide sequence composed of 512 amino acids revealed that, like Sp1 and EKLF, FKLF has three contiguous zinc fingers at the near carboxyl-terminal end. A long amino-term...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.19.5.3571
更新日期:1999-05-01 00:00:00
abstract::Genomic imprinting results in parent-of-origin-dependent monoallelic expression of selected genes. Although their importance in development and physiology is recognized, few imprinted genes have been investigated for their effects on brain function. Gnas is a complex imprinted locus whose gene products are involved in...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.25.8.3019-3026.2005
更新日期:2005-04-01 00:00:00
abstract::The murine int-1 proto-oncogene has been implicated in neural development and, when transcriptionally activated by mouse mammary tumor virus, contributes to the genesis of mammary tumors. To understand the function of the int-1 gene product in these processes, we have characterized the biochemical properties of int-1 ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.10.6.2723
更新日期:1990-06-01 00:00:00
abstract::An increased level of unpolymerized tubulin caused by depolymerization of microtubules in sea urchin larvae resulted in a rapid loss of tubulin mRNA, which was prevented by nearly complete inhibition of protein synthesis. Results of an RNA run-on assay indicated that inhibition of protein synthesis does not alter tubu...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.8.8.3518
更新日期:1988-08-01 00:00:00
abstract::Oncostatin M is a polypeptide cytokine, produced by normal and malignant hematopoietic cells, that has several in vitro activities, including the ability to inhibit growth of cultured carcinoma cells. Here we present a structural and functional comparison of two oncostatin M-related proteins (Mr 36,000 and 32,000) sec...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.10.5.1882
更新日期:1990-05-01 00:00:00
abstract::In the current study, we were interested in exploring the molecular mechanism of circular RNA DLEU2 (circRNA-DLEU2) (hsa_circ_0000488) and microRNA 496 (miR-496), as well as PRKACB, in human acute myeloid leukemia (AML) cell activities. The RNA expression levels of circRNA-DLEU2, hsa-miR-496, and PRKACB were assessed ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.00259-18
更新日期:2018-09-28 00:00:00
abstract::The positively acting regulatory gene amdR of Aspergillus nidulans coordinately regulates the expression of five structural genes involved in the catabolism of certain amides (amdS), omega amino acids (gatA and gabA), and lactams (lamA and lamB) in the presence of omega amino acid inducers. Analysis of the amdR gene s...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.10.6.3194
更新日期:1990-06-01 00:00:00