Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several lines of evidence implicate the E2F transcription factor as an important component of cell proliferation control. First, E2F binding sites are found in the promoters of genes responsive to proliferation signals and the level of E2F binding activity increases at a time when many of these genes are activated. Second, the tumour suppressor protein Rb, as well as the related p107 protein, complexes with E2F, resulting in an inhibition of E2F transcriptional activity. Third, oncogenic products of the DNA tumour viruses can dissociate these E2F complexes. We provide here direct evidence that E2F is involved in cellular proliferation control. Specifically, we demonstrate that overexpression of the E2F1 complementary DNA can activate DNA synthesis in cells that would otherwise growth-arrest, with an efficiency that is similar to that achieved by the expression of the adenovirus E1A gene. Moreover, microinjection of the E2F1 cDNA into quiescent cells can induce S-phase entry, whereas two E2F1 mutants, which are unable to transactivate the DHFR and TK promoters, are unable to induce S phase. We conclude that the E2F transcription factor plays an important role in progression into S phase and that this probably coincides with its capacity to stimulate transcription.
Nature 1993 Sep 23
PMID:Expression of transcription factor E2F1 induces quiescent cells to enter S phase. 837 27

Chromosomal band 1p36 probably harbours several neuroblastoma suppressor genes. A neuroblastoma patient has been described with a constitutional balanced translocation, t(1;17)(p36;q12-21). Cytogenetically, no loss of chromosomal material was visible. The 1p36 translocation breakpoint could therefore have inactivated one allele of a tumour suppressor gene, thus predisposing the patient to develop neuroblastoma. We localized this breakpoint by pulsed field gel electrophoresis, analysis of yeast artificial chromosomes, and fluorescence in situ hybridization. Here we report that the breakpoint is within a large cluster of small nuclear RNA U1 (RNU1) and some tRNA genes (TRE, TRN) on chromosomal band 1p36. The size of this cluster is over two megabases and it contains many other locally repeated sequences. Polyadenylated transcripts were identified for some of these sequences. In addition, the cluster is the target for integration of an adenovirus 5/SV40 hybrid virus. The translocation breakpoint maps distal of this viral integration site and proximal of marker PND.
Genes Chromosomes Cancer 1995 Sep
PMID:Balanced translocation in a neuroblastoma patient disrupts a cluster of small nuclear RNA U1 and tRNA genes in chromosomal band 1p36. 852 82

The cellular transcription factor DRTF1/E2F is implicated in the control of early cell cycle progression due to its interaction with important regulators of cellular proliferation, such as pocket proteins (for example, the retinoblastoma tumour suppressor gene product), cyclins and cyclin-dependent kinase subunits. In mammalian cells DRTF1/E2F is a heterodimeric DNA binding activity which arises when a DP protein interacts with an E2F protein. Here, we report an analysis of DRTF1/E2F in Drosophila cells, and show that many features of the pathway which regulate its transcriptional activity are conserved in mammalian cells, such as the interaction with pocket proteins, binding to cyclin A and cdk2, and its modulation by viral oncoproteins. We show that a Drosophila DP protein which can interact co-operatively with E2F proteins is a physiological DNA binding component of Drosophila DRTF1/E2F. An analysis of the expression patterns of a Drosophila DP and E2F protein indicated that DmDP is developmentally regulated and in later embryonic stages preferentially expressed in proliferating cells. In contrast, the expression of DmE2F-1 in late stage embryos occurs in a restricted group of neural cells, whereas in early embryos it is widely expressed, but in a segmentally restricted fashion. Some aspects of the mechanisms which integrate early cell cycle progression with the transcription apparatus are thus conserved between Drosophila and mammalian cells. The distinct expression patterns of DmDP and DmE2F-1 suggest that the formation of DP/E2F heterodimers, and hence DRTF1/E2F, is subject to complex regulatory cues.
J Cell Sci 1995 Sep
PMID:Functional conservation of the cell cycle-regulating transcription factor DRTF1/E2F and its pathway of control in Drosophila melanogaster. 853 34

The p16 gene has been identified as a candidate tumour suppressor gene at 9p21, a region commonly deleted in bladder cancer. We screened 140 bladder tumours and 16 cell lines for deletions and sequence variants of p16. Eight cell lines showed homozygous deletion of p16 and two had small sequence variations. All 13 tumours with small defined deletions of 9p21, 18/31 (58%) of tumours with monosomy 9 and 9/91 (10%) of tumours with no chromosome 9 loss of heterozygosity had homozygous deletion of p16. No tumour-specific sequence variants were identified. Deletion mapping revealed a nested set of deletions focused on p16. Six deletions involved p16 but not the related and adjacent gene p15 and one tumour had an intragenic deletion of p16. All other deletions involved both p16 and p15. We conclude that p16 represents the major target for deletion at 9p21 in bladder cancer.
Hum Mol Genet 1995 Sep
PMID:p16 (CDKN2) is a major deletion target at 9p21 in bladder cancer. 854 41

Loss of heterozygosity (LOH) is a frequent event in many tumours, resulting in the loss of tumour suppressor genes and ultimately magnifying the number of cells with a mutant phenotype. We have used the Dlb-1 locus as a simple quantitative assay for LOH in vivo. Mutations of the dominant Dlb-1b allele are readily detected in heterozygous (Dlb-1a/Dlb-1b) mice by the loss of histochemical staining, which results in unstained, white (Dlb-1a/Dlb-1-) ribbons on a stained background. Such ribbons are extremely rare in untreated C57BL mice which are homozygous for the dominant allele, as would be expected when two independent mutations are required. To test for LOH, we first treated the animals with a high dose of ethylnitrosourea (ENU) which induces many mutations and thus many heterozygous cells, and allowed 2 weeks for gene expression. Then the animals were treated with the test agent to determine if it could cause LOH and thus convert heterozygous mutant cells, which would not produce detectable ribbons, into homozygotes that would produce white, non-staining ribbons. Treatment with ENU alone produced a low, but detectable, frequency of mutant ribbons. Treatment with X-rays alone produced no detectable increase in the frequency of mutant ribbons. Combinations of these treatments produced additive effects, thus showing that no significant LOH was induced. The additivity of the two equal ENU treatments was unexpected, since double mutants should increase as the square of the mutant frequency.(ABSTRACT TRUNCATED AT 250 WORDS)
Mutagenesis 1995 Sep
PMID:An assay for loss of heterozygosity in vivo at the Dlb-1 locus. 854 49

Although familial cancer syndromes are rare, a knowledge of these disorders is relevant to both clinicians and basic scientists. This is exemplified by Von Hippel-Lindau (VHL) disease which is caused by germline mutations in the VHL tumour suppressor gene. This multisystem disorder provides a complex clinical problem for ophthalmologists and other specialists. In addition, recent advances in the molecular genetics of this disorder are providing novel insights into the molecular mechanisms of tumourigenesis in VHL disease and in more common nonfamilial neoplasms such as clear cell renal carcinoma and central nervous system haemangioblastoma. In this review, we describe the clinical manifestations (with particular reference to the ocular complications) and the molecular genetics of VHL disease.
Ophthalmic Genet 1995 Sep
PMID:Clinical features and molecular genetics of Von Hippel-Lindau disease. 855 82

Transforming growth factor-beta TGF-beta is the prototype for a family of extracellular proteins that affect cell proliferation and tissue differentiation. TGF-beta-related factors, including BMP-2/4, Dpp and activin, act through two types of serine/threonine kinase receptors which can form a heteromeric complex. However, the mechanism of signal transduction by these receptors is largely unknown. In Drosophila, Mad is required for signalling by Dpp. We have isolated complementary DNAs for four human Mad homologues, one of which, hMAD-4, is identical to DPC-4, a candidate tumour suppressor. hMAD-3 and -4 synergized to induce strong ligand-independent TGF-beta-like responses. When truncated at their carboxy termini, hMAD-3 and -4 act as dominant-negative inhibitors of the normal TGF-beta response. The activity of hMAD-3 and -4 was regulated by the TGF-beta receptors, and hMAD-3 but not hMAD-4 was phosphorylated and associated with the ligand-bound receptor complex. These results define hMAD-3 and -4 as effectors of the TGF-beta response and demonstrate a function for DPCA-4/hMAD-4 as a tumour suppressor.
Nature 1996 Sep 12
PMID:Receptor-associated Mad homologues synergize as effectors of the TGF-beta response. 877 81

Hereditary multiple exostoses (EXT) is an autosomal dominant condition characterized by short stature and the development of bony protuberances at the ends of all the long bones. Three genetic locl have been identified by genetic linkage analysis at chromosomes 8q24.1, 11p11-13 and 19p. The EXT1 gene on chromosome 8 was recently identified and characterized. Here, we report the isolation and characterization of the EXT2 gene. This gene shows striking sequence similarity to the EXT1 gene, and we have identified a four base deletion segregating with the phenotype. Both EXT1 and EXT2 show significant homology with one additional expressed sequence tag, defining a new multigene family of proteins with potential tumour suppressor activity.
Nat Genet 1996 Sep
PMID:The EXT2 multiple exostoses gene defines a family of putative tumour suppressor genes. 878 16

BIN1 is a novel protein that interacts with the functionally critical Myc box regions at the N terminus of the MYC oncoprotein. BIN1 is structurally related to amphiphysin, a breast cancer-associated autoimmune antigen, and RVS167, a negative regulator of the yeast cell cycle, suggesting roles in malignancy and cell cycle control. Consistent with this likelihood, BIN1 inhibited malignant cell transformation by MYC. Although BIN1 is expressed in many normal cells, its levels were greatly reduced or undetectable in 14/27 carcinoma cell lines and 3/6 primary breast tumours. Deficits were functionally significant because ectopic expression of BIN1 inhibited the growth of tumour cells lacking endogenous message. We conclude that BIN1 is an MYC-interacting protein with features of a tumour suppressor.
Nat Genet 1996 Sep
PMID:BIN1 is a novel MYC-interacting protein with features of a tumour suppressor. 878 10

Basal cell carcinoma (BCC) is the most common cancer in humans. The majority of sporadic BCCs have allele loss on chromosome 9q22 implying that inactivation of a tumour suppressor in this region is an important step in BCC formation. The gene for nevoid basal cell carcinoma syndrome (NBCCS), an autosomal dominant disorder characterized by multiple BCCs, maps to the same region and is presumed to be the tumour suppressor inactivated at this site. NBCCS has been identified recently and encodes a protein with strong homology to the Drosophila segment polarity gene, patched. Analysis of Drosophila mutants indicates that patched interacts with the hedgehog signalling pathway, repressing the expression of various hedgehog target genes including wingless, decapentaplegic and patched itself. Using single strand conformational polymorphism (SSCP) to screen human patched in 37 sporadic BCCs, we detected mutations in one-third of the tumours. Direct sequencing of two BCCs without SSCP variants revealed mutations in those tumours as well suggesting that inactivation of patched is probably a necessary step in BCC development. Northern blots and RNA in situ hybridization showed that patched is expressed at high levels in tumour cells but not normal skin suggesting that mutational inactivation of the gene leads to overexpression of mutant transcript owing to failure of a negative feedback mechanism.
Nat Genet 1996 Sep
PMID:The role of the human homologue of Drosophila patched in sporadic basal cell carcinomas. 878 9


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