Abstract:
:A transgenic gpt+ Chinese hamster cell line (G12) was found to be susceptible to carcinogenic nickel-induced inactivation of gpt expression without mutagenesis or deletion of the transgene. Many nickel-induced 6-thioguanine-resistant variants spontaneously reverted to actively express gpt, as indicated by both reversion assays and direct enzyme measurements. Since reversion was enhanced in many of the nickel-induced variant cell lines following 24-h treatment with the demethylating agent 5-azacytidine, the involvement of DNA methylation in silencing gpt expression was suspected. This was confirmed by demonstrations of increased DNA methylation, as well as by evidence indicating condensed chromatin and heterochromatinization of the gpt integration site in 6-thioguanine-resistant cells. Upon reversion to active gpt expression, DNA methylation and condensation are lost. We propose that DNA condensation and methylation result in heterochromatinization of the gpt sequence with subsequent inheritance of the now silenced gene. This mechanism is supported by direct evidence showing that acute nickel treatment of cultured cells, and of isolated nuclei in vitro, can indeed facilitate gpt sequence-specific chromatin condensation. Epigenetic mechanisms have been implicated in the actions of some nonmutagenic carcinogens, and DNA methylation changes are now known to be important in carcinogenesis. This paper further supports the emerging theory that nickel is a human carcinogen that can alter gene expression by enhanced DNA methylation and compaction, rather than by mutagenic mechanisms.
journal_name
Mol Cell Bioljournal_title
Molecular and cellular biologyauthors
Lee YW,Klein CB,Kargacin B,Salnikow K,Kitahara J,Dowjat K,Zhitkovich A,Christie NT,Costa Mdoi
10.1128/mcb.15.5.2547subject
Has Abstractpub_date
1995-05-01 00:00:00pages
2547-57issue
5eissn
0270-7306issn
1098-5549journal_volume
15pub_type
杂志文章abstract::In the yeast Saccharomyces cerevisiae, glycogen serves as a major storage carbohydrate. In a previous study, mutants with altered glycogen metabolism were isolated on the basis of the altered iodine-staining properties of colonies. We found that when glycogen produced by strains carrying the glc-1p (previously called ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.12.1.22
更新日期:1992-01-01 00:00:00
abstract::Determining the roles of Rel/NF-kappaB transcription factors in mouse skin development with loss-of-function mutants has been limited by redundancy among these proteins and by embryonic lethality associated with the absence of RelA. Using mice lacking RelA and c-rel, which survive throughout embryogenesis on a tumor n...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.24.13.5733-5745.2004
更新日期:2004-07-01 00:00:00
abstract::LAC9 is a DNA-binding protein that regulates transcription of the lactose-galactose regulon in Kluyveromyces lactis. The DNA-binding domain is composed of a zinc finger and nearby amino acids (M. M. Witte and R. C. Dickson, Mol. Cell. Biol. 8:3726-3733, 1988). The single zinc finger appears to be structurally related ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.10.10.5128
更新日期:1990-10-01 00:00:00
abstract::We have previously proposed that IQGAP1, an effector of Rac1 and Cdc42, negatively regulates cadherin-mediated cell-cell adhesion by interacting with beta-catenin and by causing the dissociation of alpha-catenin from cadherin-beta-catenin-alpha-catenin complexes and that activated Rac1 and Cdc42 positively regulate ca...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.21.6.2165-2183.2001
更新日期:2001-03-01 00:00:00
abstract::The NuA4 histone acetyltransferase (HAT) multisubunit complex is responsible for acetylation of histone H4 and H2A N-terminal tails in yeast. Its catalytic component, Esa1, is essential for cell cycle progression, gene-specific regulation and has been implicated in DNA repair. Almost all NuA4 subunits have clear homol...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.24.5.1884-1896.2004
更新日期:2004-03-01 00:00:00
abstract::The Msh2-Msh3 heterodimer recognizes various DNA mispairs, including loops of DNA ranging from 1 to 14 nucleotides and some base-base mispairs. Homology modeling of the mispair-binding domain (MBD) of Msh3 using the related Msh6 MBD revealed that mismatch recognition must be different, even though the MBD folds must b...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.01558-09
更新日期:2010-07-01 00:00:00
abstract::Oncoprotein E2a/Pbx1 is produced by the t(1;19) chromosomal translocation of human pre-B acute lymphoblastic leukemia. E2a/Pbx1 blocks differentiation of primary myeloid progenitors but, paradoxically, induces apoptosis in established pre-B-cell lines, and no transforming function of E2a/Pbx1 has been reported in cult...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.24.3.1256-1269.2004
更新日期:2004-02-01 00:00:00
abstract::Glucocorticoid-induced leucine zipper (GILZ) is a leucine zipper protein, whose expression is augmented by dexamethasone (DEX) treatment and downregulated by T-cell receptor (TCR) triggering. Stable expression of GILZ in T cells mimics some of the effects of glucocorticoid hormones (GCH) in GCH-mediated immunosuppress...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.22.22.7929-7941.2002
更新日期:2002-11-01 00:00:00
abstract::The c-abl protooncogene is unusual in two respects; it has multiple, widely space N-terminal coding exons transcribed by different promoters, and it is the target of the translocations that form the Philadelphia chromosome found in cells of chronic myelogenous leukemia patients. To understand the organization of the g...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.7.9.3231
更新日期:1987-09-01 00:00:00
abstract::During spermatogenesis, several genes are expressed in a germ cell-specific manner. Previous studies have demonstrated that rat and mouse spermatogenic cells produce a 1,700-nucleotide proenkephalin RNA, while somatic cells that express the proenkephalin gene contain a 1,450-nucleotide transcript. Using cDNA cloning, ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.10.7.3717
更新日期:1990-07-01 00:00:00
abstract::NF-κB activation is a critical component in the transcriptional response to hypoxia. However, the underlying mechanisms that control its activity under these conditions are unknown. Here we report that under hypoxic conditions, IκB kinase (IKK) activity is induced through a calcium/calmodulin-dependent kinase 2 (CaMK2...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.00409-10
更新日期:2010-10-01 00:00:00
abstract::beta-Site beta-amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) is the beta-secretase in vivo for processing APP to generate amyloid beta protein (Abeta). Abeta deposition in the brain is the hallmark of Alzheimer's disease (AD) neuropathology. Inhibition of BACE1 activity has major pharmaceutical potential f...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.26.9.3353-3364.2006
更新日期:2006-05-01 00:00:00
abstract::Using a Saccharomyces cerevisiae strain containing an integrated copy of an H2A-lacZ fusion gene, we screened for mutants which overexpressed beta-galactosidase as a way to identify genes which regulate transcription of the histone genes. Five recessive mutants with this phenotype were shown to contain altered regulat...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.7.12.4204
更新日期:1987-12-01 00:00:00
abstract::Hepatocyte growth factor (HGF), a cytokine with multiple functions, exhibits cell-type-specific as well as cytokine- and steroid hormone-regulated expression. The HGF gene is known to be expressed predominately in mesenchymal but not in epithelial cells. In this study, we report the identification of a cell-type-speci...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.14.11.7046
更新日期:1994-11-01 00:00:00
abstract::We have previously proposed that the upstream regions of the human cardiac actin gene contain sequences that interact with muscle-specific factors with direct high-level transcription of this gene in differentiated muscle cells. In this study we showed that these factors already accumulate in the dividing myoblasts of...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.6.6.2137
更新日期:1986-06-01 00:00:00
abstract::The tetradecanoyl phorbol acetate-induced sequence 7 gene (tis7) is regulated during cell fate processes and functions as a transcriptional coregulator. Here, we describe the generation and analysis of mice lacking the tis7 gene. Surprisingly, TIS7 knockout mice show no gross histological abnormalities and are fertile...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.24.8.3514-3525.2004
更新日期:2004-04-01 00:00:00
abstract::macroH2A histone variants have been implicated to function in gene silencing by several studies, including ones showing a preferential association of macroH2A on the inactive X chromosome. To examine macroH2A function in vivo, we knocked out macroH2A1. macroH2A1 knockout mice are viable and fertile. A broad screen of ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.02334-06
更新日期:2007-04-01 00:00:00
abstract::The imprinted expression of the H19 and Igf2 genes in the mouse is controlled by an imprinting control center (ICR) whose activity is regulated by parent-of-origin differences in methylation. The only protein that has been implicated in ICR function is the zinc-finger protein CTCF, which binds at multiple sites within...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.25.10.3855-3863.2005
更新日期:2005-05-01 00:00:00
abstract::1-Nitropyrene has been shown in bacterial assays to be the principal mutagenic agent in diesel emission particulates. It has also been shown to be mutagenic in human fibroblasts and carcinogenic in animals. To investigate the kinds of mutations induced by this carcinogen and compare them with those induced by a struct...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.8.8.3364
更新日期:1988-08-01 00:00:00
abstract::We have studied leucine transport in several Chinese hamster-human hybrid cell lines obtained by fusion of a temperature-sensitive line of Chinese hamster ovary cells, ts025C1, and normal human leukocytes. A hybrid cell line exhibiting a twofold increase in L-leucine uptake over that in the parental cell line was foun...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.4.3.475
更新日期:1984-03-01 00:00:00
abstract::Members of the type II nuclear hormone receptor subfamily (e.g., thyroid hormone receptors [TRs], retinoic acid receptors, retinoid X receptors [RXRs], vitamin D receptor, and the peroxisome proliferator-activated receptors) bind to their response sequences with or without ligand. In the absence of ligand, these DNA-b...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.21.7.2298-2311.2001
更新日期:2001-04-01 00:00:00
abstract::We have measured the frequency of meiotic recombination between marked Ty elements in the Saccharomyces cerevisiae genome. These recombination events were usually nonreciprocal (gene conversions) and sometimes involved nonhomologous chromosomes. The frequency of ectopic gene conversion among Ty elements appeared lower...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.8.7.2942
更新日期:1988-07-01 00:00:00
abstract::Activation-induced deaminase (AID) is essential for class switch recombination and somatic hypermutation, and it has the ability to deaminate single-stranded DNA at cytidines. Mammalian class switch regions form R-loops upon transcription in the physiological orientation. The displaced DNA strand of an R-loop is force...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.25.5.1730-1736.2005
更新日期:2005-03-01 00:00:00
abstract::The Rex protein of human T-cell leukemia virus type 1, like the functionally equivalent Rev protein of human immunodeficiency virus type 1, contains a leucine-rich activation domain that specifically interacts with the human nucleoporin-like Rab/hRIP cofactor. Here, this Rex sequence is shown to function also as a pro...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.16.8.4207
更新日期:1996-08-01 00:00:00
abstract::ABFI (ARS-binding protein I) is a yeast protein that binds specific DNA sequences associated with several autonomously replicating sequences (ARSs). ABFI also binds sequences located in promoter regions of some yeast genes, including DED1, an essential gene of unknown function that is transcribed constitutively at a h...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.10.3.887
更新日期:1990-03-01 00:00:00
abstract::Abelson murine leukemia virus (A-MuLV), a retrovirus that expresses the v-abl oncogene, characteristically induces pre-B-cell lymphomas following in vivo infection of BALB/c mice or in vitro infection of suspensions of fetal liver or bone marrow cells. ABL-MYC, a retrovirus that expresses both v-abl and c-myc, induces...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.13.4.2578
更新日期:1993-04-01 00:00:00
abstract::Activation of oncogenes or inhibition of WEE1 kinase deregulates cyclin-dependent kinase (CDK) activity and leads to replication stress; however, the underlying mechanism is not understood. We now show that elevation of CDK activity by inhibition of WEE1 kinase rapidly increases initiation of replication. This leads t...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.00412-12
更新日期:2012-10-01 00:00:00
abstract::Phosphoinositide-specific phospholipase C (PLC) is a key enzyme in phosphoinositide turnover and is involved in a variety of physiological functions. We analyzed PLCdelta1 knockout mice and found that PLCdelta1 is required for the maintenance of skin homeostasis. However, there were no remarkable abnormalities except ...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.25.24.10979-10988.2005
更新日期:2005-12-01 00:00:00
abstract::A novel protein, p55CDC, has been identified in cycling mammalian cells. This transcript is readily detectable in all exponentially growing cell lines but disappears when cells are chemically induced to fall out of the cell cycle and differentiate. The p55CDC protein appears to be essential for cell division, since tr...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/mcb.14.5.3350
更新日期:1994-05-01 00:00:00
abstract::The intracellular signaling mechanisms underlying the pathogenesis of cardiac diseases are not fully understood. We report here that selective deletion of Shp2, an SH2-containing cytoplasmic tyrosine phosphatase, in striated muscle results in severe dilated cardiomyopathy in mice, leading to heart failure and prematur...
journal_title:Molecular and cellular biology
pub_type: 杂志文章
doi:10.1128/MCB.01661-08
更新日期:2009-01-01 00:00:00