scholarly journals Identification of positively and negatively acting elements regulating expression of the E2F2 gene in response to cell growth signals.

1997 ◽  
Vol 17 (9) ◽  
pp. 5227-5235 ◽  
Author(s):  
R Sears ◽  
K Ohtani ◽  
J R Nevins
Keyword(s):  
Cell Growth ◽  
Binding Sites ◽  
Sequence Comparison ◽  
Gene Promoter ◽  
Growth Stimulation ◽  
Gene Products ◽  
Quiescent Cells ◽  
Expression Of Genes ◽  
E Box ◽  
Mammalian Cell Growth

Mammalian cell growth is governed by regulatory activities that include the products of genes such as c-myc and ras that act early in G1, as well as the E2F family of transcription factors that accumulate later in G1 to regulate the expression of genes involved in DNA replication. Previous work has shown that the expression of the E2F1, E2F2, and E2F3 gene products is tightly regulated by cell growth. To further explore the mechanisms controlling accumulation of E2F activity, we have isolated genomic sequences flanking the 5' region of the E2F2 coding sequence. Various assays demonstrate promoter activity in this sequence that reproduces the normal control of E2F2 expression during a growth stimulation. Sequence comparison reveals the presence of a variety of known transcription factor binding sites, including E-box elements that are consensus Myc binding sites, as well as E2F binding sites. We demonstrate that the E-box elements, which we show can function as Myc-responsive sites, contribute in a positive fashion to promoter function. We also find that E2F-dependent negative regulation in quiescent cells plays a significant role in the cell growth-dependent control of the promoter, similar to the regulation of the E2F1 gene promoter.

scholarly journals Complex Transcriptional Regulatory Mechanisms Control Expression of the E2F3 Locus

2000 ◽  
Vol 20 (10) ◽  
pp. 3633-3639 ◽  
Author(s):  
Monique R. Adams ◽  
Rosalie Sears ◽  
Faison Nuckolls ◽  
Gustavo Leone ◽  
Joseph R. Nevins
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Binding Sites ◽  
Critical Role ◽  
Growth Control ◽  
Constitutive Expression ◽  
Growth Stimulation ◽  
Positive Control ◽  
Negative Control ◽  
Transcriptional Regulatory Mechanisms

ABSTRACT E2F transcription activity has been shown to play a critical role in cell growth control, regulating the expression of a variety of genes that encode proteins important for the initiation of DNA replication and cell cycle regulation. We have shown that the E2F3 locus encodes two protein products: the E2F3a product, which is tightly regulated by cell growth, and the E2F3b product, which is constitutively expressed throughout the cell cycle. To further explore the mechanism controlling the expression of the two E2F3 gene products, we analyzed the genomic sequences flanking the 5′ region of E2F3a and E2F3b. We find that a series of E2F binding sites confer negative control on the E2F3a promoter in quiescent cells, similar to the control of the E2F1 and E2F2 promoters. In addition, a group of E-box elements, which are Myc binding sites, confer responsiveness to Myc and are necessary for full activation of the E2F3a promoter in response to growth stimulation. Based on these results and past experiments, it appears that the E2F1, E2F2, and E2F3a genes are similarly regulated by growth stimulation, involving a combination of E2F-dependent negative control and Myc-mediated positive control. In contrast, the constitutive expression of the E2F3b gene more closely reflects the control of expression of the E2F4 and E2F5 genes.

scholarly journals Expression of the HsOrc1 gene, a human ORC1 homolog, is regulated by cell proliferation via the E2F transcription factor.

1996 ◽  
Vol 16 (12) ◽  
pp. 6977-6984 ◽  
Author(s):  
K Ohtani ◽  
J DeGregori ◽  
G Leone ◽  
D R Herendeen ◽  
T J Kelly ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Dna Replication ◽  
Cell Growth ◽  
Origin Recognition Complex ◽  
Growth Control ◽  
Growth Stimulation ◽  
Transcription Control ◽  
Quiescent Cells ◽  
G1 Cyclin ◽  
Initiation Of Dna Replication

The initiation of DNA replication in Saccharomyces cerevisiae requires the action of a multisubunit complex of six proteins known as the origin recognition complex (ORC). The identification of higher eukaryotic homologs of several ORC components suggests a universal role for this complex in DNA replication. We now demonstrate that the expression of one of these homologs is regulated by cell proliferation. Expression of the human Orc1 gene (HsOrc1) is low in quiescent cells, and it is then dramatically induced upon stimulation of cell growth. In contrast, expression of the HsOrc2 gene does not appear to be similarly regulated. We have isolated the promoter that regulates HsOrc1 transcription, and we show that the promoter confers cell growth-dependent expression. We also demonstrate that the cell growth control is largely the consequence of E2F-dependent negative transcription control in quiescent cells. Activation of HsOrc1 transcription following growth stimulation requires G1 cyclin-dependent kinase activity, and forced E2F1 expression can bypass this requirement. These results thus provide a direct link between the initiation of DNA replication and the cell growth regulatory pathway involving G1 cyclin-dependent kinases, the Rb tumor suppressor, and E2F.

scholarly journals RAD51 May Regulate the Expression of Genes Involved in Autophagy Through Interaction with E-box Binding Proteins in Cancer Cell Lines

2020 ◽  
Author(s):  
Keunsoo Kang ◽  
Yoonjung Choi ◽  
Hyeonjin Moon ◽  
Minjin Seo ◽  
Jahyun Yoon ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Cell Lines ◽  
Binding Sites ◽  
Binding Proteins ◽  
Binding Motif ◽  
Expression Of Genes ◽  
Genome Wide ◽  
E Box ◽  
Autophagy Pathway

RAD51 is a recombinase that plays a pivotal role in homologous recombination. Although the role of RAD51 in homologous recombination has been extensively studied, it is unclear whether RAD51 can be involved in gene regulation as a co-factor. In this study, we found in silico evidence that RAD51 may contribute to the regulation of genes involved in the autophagy pathway through interaction with E-box proteins such as USF1, USF2, and/or MITF in GM12878, HepG2, K562, and MCF-7 cell lines. The canonical USF binding motif (CACGTG) was significantly identified at RAD51 binding sites in all four cell lines. In addition, genome-wide USF1, USF2, and/or MITF-binding regions significantly coincided with the RAD51-binding sites in the same cell line. Interestingly, the promoters of genes associated with the autophagy pathway were significantly occupied by RAD51 in all four cell lines. Taken together, these results predicted a novel role of RAD51 that had not been addressed previously, and provided evidence that RAD51 could possibly be involved in regulating genes associated with the autophagy pathway, through interaction with E-box binding proteins.

scholarly journals Investigations of the mechanism by which mammalian cell growth is inhibited by N1N12-bis(ethyl)spermine

1993 ◽  
Vol 291 (1) ◽  
pp. 131-137 ◽  
Author(s):  
L Albanese ◽  
R J Bergeron ◽  
A E Pegg
Keyword(s):  
Mitochondrial Dna ◽  
Cell Growth ◽  
Cell Lines ◽  
Ornithine Decarboxylase ◽  
Polyamine Analogues ◽  
Proliferative Effect ◽  
L1210 Cells ◽  
Inhibition Of Growth ◽  
Variant Cell ◽  
Mammalian Cell Growth

N1N12-Bis(ethyl)spermine (BESM) and related compounds are powerful inhibitors of cell growth that may have potential as anti-neoplastic agents [Bergeron, Neims, McManis, Hawthorne, Vinson, Bortell and Ingeno (1988) J. Med. Chem. 31, 1183-1190]. The mechanism by which these compounds bring about their effects was investigated by using variant cell lines in which processes thought to be altered by these agents are perturbed. Comparisons between the response of these cells and of their parental equivalents to BESM, N1N11-bis(ethyl)norspermine, N1N14-bis(ethyl)homospermine and N1N8-bis(ethyl)spermidine were then made. It was found that D-R cells, an L1210-derived line that over-expresses ornithine decarboxylase, were not resistant to these compounds. This indicates that the decrease in ornithine decarboxylase is not critical for the action of the compounds on cell growth. Furthermore, although polyamine levels were decreased in the D-R cells, the content was not totally depleted, indicating that such depletion is also not essential for the anti-proliferative effect. Two cell lines lacking mitochondrial DNA (human 143B206 cells and chicken DU3 cells) did not differ in sensitivity to BESM from their parental 143BTK- and DU24 cells. Furthermore, the inhibition of respiration in L1210 cells in response to BESM developed more slowly than the inhibition of growth. Thus it appears that the inhibitions of mitochondrial DNA synthesis and of mitochondrial respiration are also not primary factors in the anti-proliferative effects of these polyamine analogues. The inhibition of growth did, however, correlate with the intracellular accumulation of the analogues. It appears that the bis(ethyl)polyamine derivatives act by binding to intracellular target molecules and preventing macromolecular synthesis. The decline in normal polyamines may facilitate such binding, but is not essential for growth arrest.

Mammalian genes coordinately regulated by growth arrest signals and DNA-damaging agents

1989 ◽  
Vol 9 (10) ◽  
pp. 4196-4203
Author(s):  
A J Fornace ◽  
D W Nebert ◽  
M C Hollander ◽  
J D Luethy ◽  
M Papathanasiou ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Growth ◽  
Growth Arrest ◽  
Homozygous Deletion ◽  
Negative Control ◽  
Cdna Clones ◽  
Growth Cessation ◽  
Dna Damaging Agents ◽  
Mammalian Cell Growth ◽  
Serum Reduction

More than 20 different cDNA clones encoding DNA-damage-inducible transcripts in rodent cells have recently been isolated by hybridization subtraction (A. J. Fornace, Jr., I. Alamo, Jr., and M. C. Hollander, Proc. Natl. Acad. Sci. USA 85:8800-8804, 1988). In most cells, one effect of DNA damage is the transient inhibition of DNA synthesis and cell growth. We now show that five of our clones encode transcripts that are increased by other growth cessation signals: growth arrest by serum reduction, medium depletion, contact inhibition, or a 24-h exposure to hydroxyurea. The genes coding for these transcripts have been designated gadd (growth arrest and DNA damage inducible). Two of the gadd cDNA clones were found to hybridize at high stringency to transcripts from human cells that were induced after growth cessation signals or treatment with DNA-damaging agents, which indicates that these responses have been conserved during mammalian evolution. In contrast to results with growth-arrested cells that still had the capacity to grow after removal of the growth arrest conditions, no induction occurred in HL60 cells when growth arrest was produced by terminal differentiation, indicating that only certain kinds of growth cessation signals induce these genes. All of our experiments suggest that the gadd genes are coordinately regulated: the kinetics of induction for all five transcripts were similar; in addition, overexpression of gadd genes was found in homozygous deletion c14CoS/c14CoS mice that are missing a small portion of chromosome 7, suggesting that a trans-acting factor encoded by a gene in this deleted portion is a negative effector of the gadd genes. The gadd genes may represent part of a novel regulatory pathway involved in the negative control of mammalian cell growth.

The HML mating-type cassette of Saccharomyces cerevisiae is regulated by two separate but functionally equivalent silencers

1989 ◽  
Vol 9 (11) ◽  
pp. 4621-4630
Author(s):  
D J Mahoney ◽  
J R Broach
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Binding Sites ◽  
The Other ◽  
Functional Domains ◽  
Gene Products ◽  
Cis Acting ◽  
Full Expression ◽  
Mating Type Genes ◽  
Chromosome Iii

Mating-type genes resident in the silent cassette HML at the left arm of chromosome III are repressed by the action of four SIR gene products, most likely mediated through two cis-acting sites located on opposite sides of the locus. We showed that deletion of either of these two cis-acting sites from the chromosome did not yield any detectable derepression of HML, while deletion of both sites yielded full expression of the locus. In addition, each of these sites was capable of exerting repression of heterologous genes inserted in their vicinity. Thus, HML expression is regulated by two independent silencers, each fully competent for maintaining repression. This situation was distinct from the organization of the other silent locus, HMR, at which a single silencer served as the predominant repressor of expression. Examination of identifiable domains and binding sites within the HML silencers suggested that silencing activity can be achieved by a variety of combinations of various functional domains.

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