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)

The p53 gene is a tumour suppressor gene which has a fundamental role in cell cycle control and division, and in mammals certain genotoxic agents induce specific mutations in p53, leading to tumourigenesis. Fish have been investigated as models for studying carcinogens, but as yet very little data exists that links exposure to specific chemicals with the aetiology of tumours found in wild populations. In this study, p53 was sequenced from five species of fish with a view to the possible use of mutations in the highly conserved domains of p53 to identify genotoxins in the aquatic environment. A 0.8 kb fragment of the cDNA encompassing the conserved DNA-binding domain of p53 was sequenced in three Oncorhynchus salmonid fish: coho (O. kisutch), chum (O. keta), and chinook (O. tshawytscha) and full-length p53 cDNAs were sequenced in the puffer fish (Tetraodon miurus) and the barbel (Barbus barbus). The full-length puffer fish and barbel p53 cDNAs were 1834 bp and 1790 bp in length, encoding a 367 aa protein and a 369 aa protein, respectively. The deduced aa sequences of the p53 cDNA in the Oncorhynchus salmon shared a 100% identity in the five conserved regions (I-V). Comparisons of the deduced aa sequences for puffer fish and barbel p53 with other fish p53s revealed a high homology within the conserved DNA binding domain (68-86% for puffer fish and between 66-88% for barbel). "Conserved" domain I was not highly conserved in fish, as it is in mammals, and, therefore, conserved domains II-V are most likely to provide the valuable sequences in fish p53 for use in mutational studies to fingerprint genotoxins in the aquatic environment.
Environ Mol Mutagen 1999
PMID:Fish p53 as a possible biomarker for genotoxins in the aquatic environment. 1033 19

von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome caused by germline mutations of the VHL tumour suppressor gene. The VHL gene product, pVHL, forms multiprotein complexes that contain elongin B, elongin C and Cul-2, and negatively regulates hypoxia-inducible mRNAs. pVHL is suspected to play a role in ubiquitination given the similarity of elongin C and Cul-2 with Skp1 and Cdc53, respectively. pVHL can also interact with fibronectin and is required for the assembly of a fibronectin matrix. Finally, pVHL, at least indirectly, plays a role in the ability of cells to exit the cell cycle. Thus, pVHL is a tumour suppressor protein that regulates angiogenesis, extracellular matrix formation and the cell cycle.
Mol Med Today 1999 Jun
PMID:The von Hippel-Lindau tumour suppressor protein: new perspectives. 1036 21

Germline mutations in the tumour suppressor gene PTEN have been implicated in two hamartoma syndromes that exhibit some clinical overlap, Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba syndrome (BRR). PTEN maps to 10q23 and encodes a dual specificity phosphatase, a substrate of which is phosphatidylinositol 3,4,5-triphosphate, a phospholipid in the phosphatidylinositol 3-kinase pathway. CS is characterized by multiple hamartomas and an increased risk of benign and malignant disease of the breast, thyroid and central nervous system, whilst the presence of cancer has not been formally documented in BRR. The partial clinical overlap in these two syndromes is exemplified by the hallmark features of BRR: macrocephaly and multiple lipomas, the latter of which occur in a minority of individuals with CS. Additional features observed in BRR, which may also occur in a minority of CS patients, include Hashimoto's thyroiditis, vascular malformations and mental retardation. Pigmented macules of the glans penis, delayed motor development and neonatal or infant onset are noted only in BRR. In this study, constitutive DNA samples from 43 BRR individuals comprising 16 sporadic and 27 familial cases, 11 of which were families with both CS and BRR, were screened for PTEN mutations. Mutations were identified in 26 of 43 (60%) BRR cases. Genotype-phenotype analyses within the BRR group suggested a number of correlations, including the association of PTEN mutation and cancer or breast fibroadenoma in any given CS, BRR or BRR/CS overlap family ( P = 0.014), and, in particular, truncating mutations were associated with the presence of cancer and breast fibroadenoma in a given family ( P = 0.024). Additionally, the presence of lipomas was correlated with the presence of PTEN mutation in BRR patients ( P = 0.028). In contrast to a prior report, no significant difference in mutation status was found in familial versus sporadic cases of BRR ( P = 0.113). Comparisons between BRR and a previously studied group of 37 CS families suggested an increased likelihood of identifying a germline PTEN mutation in families with either CS alone or both CS and BRR when compared with BRR alone ( P = 0.002). Among CS, BRR and BRR/CS overlap families that are PTEN mutation positive, the mutation spectra appear similar. Thus, PTEN mutation-positive CS and BRR may be different presentations of a single syndrome and, hence, both should receive equal attention with respect to cancer surveillance.
Hum Mol Genet 1999 Aug
PMID:PTEN mutation spectrum and genotype-phenotype correlations in Bannayan-Riley-Ruvalcaba syndrome suggest a single entity with Cowden syndrome. 1040 Sep 93

Tumour suppressor genes and oncogenes that control proliferation and apoptosis are known to play an important role in embryogenesis, second trimester fetal oocyte loss, adult ovulation, and in adult male testicular degeneration. We have examined tumour suppressor genes, oncogenes and oestrogen receptors during first trimester human gonadal differentiation to investigate their role at this crucial phase in development. Immunohistochemistry was used to localize the gene products of Bcl-2, c-erB-2, c-myc, p53, nm23 and oestrogen receptor. As gonadal development occurred at 6-12 weeks gestation, a changing pattern of expression was observed that varied in different cell types. The oestrogen receptor was not present in oogonia, spermatogonia and supporting cells during the first trimester. This study highlights the importance of oncogenes and tumour suppressor genes in first trimester gonadal development.
Mol Hum Reprod 1999 Aug
PMID:Oncogenes and tumour suppressor genes in first trimester human fetal gonadal development. 1042 1

During the development of cancer a series of specific genetic alterations have to occur in a stepwise fashion to transform a normal somatic cell into a malignant tumor cell. These genetic changes can be roughly divided in two groups: mutations in proto-oncogenes that result in a constantly activated gene product and mutations in tumor-suppressor genes that result in loss of function. While oncogenic mutations often have a dominant phenotype and mutation of one allele is sufficient for activation, in general both alleles of a tumor suppressor gene have to be disrupted to abolish its function. The requested specificity for activating mutations in proto-oncogenes is high, since only a limited number of mutations at specific sites result in an activated protein. In contrast, disruption of a tumor suppressor gene can be accomplished via various mechanisms. Familial cancers often contain a germline mutation in one allele of a tumor suppressor gene. In tumors, the second allele is then frequently lost by genetic alterations that also affect the heterozygous state of multiple loci adjacent to the tumor suppressor gene. Genetic events especially, such as mitotic recombination, chromosome loss and deletion, are frequently responsible for the loss of the functional allele of heterozygous mutant tumor suppressor genes. We generated an Aprt(+/-) mouse model that allows us to study in detail the nature of the alterations that lead to loss of the wild-type Aprt allele in somatic cells. These genetic changes are thought to be analogous to those occurring at autosomal tumour suppressor genes, where they may contribute to the development of cancer. Furthermore, this mouse model allows determination of the extent and mechanisms by which chemical carcinogens induce loss of heterozygosity and identification of the nature of the DNA adducts responsible.
Environ Mol Mutagen 1999
PMID:Heterozygous Aprt mouse model: detection and study of a broad range of autosomal somatic mutations in vivo. 1052 30

X-linked lymphoproliferative disease (XLP) is a primary immunodeficiency, which most often manifests itself after Epstein-Barr virus (EBV) infection. The main clinical phenotypes include fulminant or fatal infectious mononucleosis, dysgammaglobulinaemia and malignant lymphoma. We have recently cloned the SH2D1A gene, which has been shown to be mutated in approximately 70% of XLP patients. Now we report five novel SH2D1A mutations in patients from five unrelated XLP families. No mutations were found in another three XLP families. In three boys with early onset non-Hodgkin lymphoma (NHL) from two unrelated families a deletion of SH2D1A exon 1 and a splice site mutation were found, respectively. These patients did not show any laboratory or clinical signs of a previous EBV infection. A fourth EBV-uninfected and unrelated boy with a stop mutation in the SH2D1A gene shows only signs of dysgammaglobulinaemia. Development of dysgamma-globulinaemia and lymphoma without evidence of prior EBV infection in four of our patients suggests that EBV is unrelated to these phenotypes, in contrast to fulminant or fatal infectious mononucleosis. The role of SH2D1A as a putative tumour suppressor gene remains to be investigated.
Hum Mol Genet 1999 Dec
PMID:Epstein-Barr virus-negative boys with non-Hodgkin lymphoma are mutated in the SH2D1A gene, as are patients with X-linked lymphoproliferative disease (XLP). 1055 88

E6 is an oncoprotein implicated in cervical cancers, produced by "high-risk" human papillomaviruses. E6 is thought to promote tumorigenesis by stimulating cellular degradation of the tumour suppressor p53, but it might display other activities. Sequence similarity was recently detected between E6 and endonuclease VII, a protein of phage T4 that recognizes and cleaves four-way DNA junctions. Here, we purified recombinant E6 proteins and demonstrated that high-risk E6 s bind selectively to four-way junctions in a structure-dependent manner. Several residues in the C-terminal zinc-binding domain, the region of E6 similar to endonuclease VII, are necessary for the junction-binding activity. E6 binds to the junction as a monomer. Comparative electrophoresis shows that E6-bound junctions migrate in an extended square conformation. Magnesium inhibits the electrophoretic migration of the complexes but does not seem to influence their formation at equilibrium. This work is the first demonstration of specific binding of purified active E6 to a well-characterized DNA ligand, and suggests new modes of action of E6 in oncogenesis.
J Mol Biol 2000 Mar 10
PMID:HPV oncoprotein E6 is a structure-dependent DNA-binding protein that recognizes four-way junctions. 1069 26

Germline PTEN mutations cause Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba syndrome (BRR), two hamartoma-tumour syndromes, and somatic PTEN alterations have been shown to participate, to a greater or lesser extent, in a wide variety of sporadic neoplasia. PTEN is a tumour suppressor and dual-specificity phosphatase which affects apoptosis via its lipid phosphatase activity in the phosphoinositol-3-kinase and AKT pathway as well as inhibiting cell spreading via the focal adhesion kinase pathway. CS and BRR share some features, such as hamartomas and lipomatosis. To determine whether other syndromes characterized by overgrowth and lipomas are part of the PTEN syndrome spectrum, we ascertained six individuals with overgrowth and lipomas but who did not meet the diagnostic criteria for CS or BRR. Five had Proteus syndrome and one, a Proteus-like syndrome. When germline DNA and DNA from at least one involved tissue per case were examined for PTEN mutations, only the Proteus-like patient was found to harbour a germline R335X mutation. Interestingly, a lipomatous mass, an epidermoid naevus and arteriovenous malformation tissue, all of which were sampled from physically distinct sites, were all found to carry a second hit R130X mutation on the allele opposite the germline R335X. Both mutations have been described in CS and BRR. We postulate that the second hit, R130X, occurred early in embryonic development and may even represent germline mosaicism. Thus, PTEN may be involved in Proteus-like syndrome with its implications for cancer development in the future.
Hum Mol Genet 2000 Mar 22
PMID:Germline and germline mosaic PTEN mutations associated with a Proteus-like syndrome of hemihypertrophy, lower limb asymmetry, arteriovenous malformations and lipomatosis. 1074 83

Pleural malignant mesothelioma (MM) shows poor survival, regardless of tumour stage at diagnosis. MM is unresponsive to present treatment regimens and new protocols are desperately needed. The localised nature, the potential accessibility, and the relative lack of distant metastases make MM a particularly attractive candidate for somatic gene therapy. A common target for cancer gene therapy is the tumour suppressor protein p53. p53 does not seem to be mutated or deleted in MM, but it can be inactivated by binding to other proteins, like mdm2 and SV40 large T antigen. We tested the effects of a replication-deficient adenoviral vector carrying wild-type p53 cDNA in human MM cells. Our results show that >95% of MM cells were efficiently infected with 25 multiplicity of infection (MOI) of vector. Wild-type p53 was effectively expressed resulting in >80% inhibition of proliferation in MM cells. AdCMV.p53 infection induced apoptosis while controls did not show any evident morphological alterations. Ex vivo p53 gene transfer experiments inhibited tumourigenesis in nude mice. In vivo, direct intratumour injection of AdCMV.p53 arrested tumour growth and prolonged survival of treated mice. These results indicate that p53-gene therapy should be strongly exploited for clinical trials in MM patients.
Int J Mol Med 2000 Jun
PMID:Adenovirus-mediated wild-type p53 overexpression reverts tumourigenicity of human mesothelioma cells. 1081 6

Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominantly inherited cancer syndrome (OMIM 131100), with tumours in several endocrine glands. In 1997 the responsible tumour suppressor gene was identified and recently it was shown that menin, its encoded protein, represses JunD-activated gene expression. Although many MEN 1 patients have been investigated both clinically and genetically, no genotype-phenotype correlation has been found yet. The vast majority of MEN1 gene mutations involve point mutations. We describe a patient in whom a 26 base pair deletion in the MEN1 gene, comprising part of exon 3 and part of intron 3, causes activation of a cryptic donor splice site at the beginning of exon 3. This germline mutation results in an in frame deletion of 105 nucleotides in MEN1 gene mRNA, i.e. an internal deletion of 35 amino acids in the menin protein. Since the deleted region of menin has been implicated in binding to JunD, this may explain the tumourigenic effect of this mutation. The knowledge of this MEN1 gene germline defect, may be used for presymptomatic identification of MEN 1 disease gene-carriers among family-members of this proband. This enables early detection of tumour development, timely treatment and genetic counseling.
Int J Mol Med 2000 Jun
PMID:Internally shortened menin protein as a consequence of alternative RNA splicing due to a germline deletion in the multiple endocrine neoplasia type 1 gene. 1081 10


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