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1.
Clin Pharmacol Ther ; 99(2): 146-8, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26517013

ABSTRACT

The direct-to-consumer genetic testing debate reached a fever pitch in November 2013 when the US Food and Drug Administration (FDA) instructed 23andMe to discontinue marketing and sale of their Personal Genome Service. In 2015, 23andMe emerged with FDA approval to market a carrier test for Bloom syndrome only, and plans to release additional reports. The dust has settled and it is time to ask: What have we learned, and where do we go from here?


Subject(s)
Delivery of Health Care/trends , Direct-To-Consumer Screening and Testing/trends , Genetic Testing/trends , Access to Information , Bloom Syndrome/diagnosis , Bloom Syndrome/genetics , Genome , Humans , United States , United States Food and Drug Administration
2.
Public Health Genomics ; 15(1): 22-30, 2012.
Article in English | MEDLINE | ID: mdl-21654153

ABSTRACT

BACKGROUND/AIMS: To predict the potential public health impact of personal genomics, empirical research on public perceptions of these services is needed. In this study, 'early adopters' of personal genomics were surveyed to assess their motivations, perceptions and intentions. METHODS: Participants were recruited from everyone who registered to attend an enrollment event for the Coriell Personalized Medicine Collaborative, a United States-based (Camden, N.J.) research study of the utility of personalized medicine, between March 31, 2009 and April 1, 2010 (n = 369). Participants completed an Internet-based survey about their motivations, awareness of personalized medicine, perceptions of study risks and benefits, and intentions to share results with health care providers. RESULTS: Respondents were motivated to participate for their own curiosity and to find out their disease risk to improve their health. Fewer than 10% expressed deterministic perspectives about genetic risk, but 32% had misperceptions about the research study or personal genomic testing. Most respondents perceived the study to have health-related benefits. Nearly all (92%) intended to share their results with physicians, primarily to request specific medical recommendations. CONCLUSION: Early adopters of personal genomics are prospectively enthusiastic about using genomic profiling information to improve their health, in close consultation with their physicians. This suggests that early users (i.e. through direct-to-consumer companies or research) may follow up with the health care system. Further research should address whether intentions to seek care match actual behaviors.


Subject(s)
Community Participation , Genetic Predisposition to Disease , Genomics , Motivation , Perception , Precision Medicine , Adolescent , Adult , Aged , Female , Humans , Information Dissemination , Male , Middle Aged , Prospective Studies , Young Adult
3.
Diabetologia ; 54(4): 783-8, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21188353

ABSTRACT

AIMS/HYPOTHESIS: Chronically elevated blood glucose (hyperglycaemia) is the primary indicator of type 2 diabetes, which has a prevalence that varies considerably by ethnicity in the USA, with African-Americans disproportionately affected. Genome-wide association studies (GWASs) have significantly enhanced our understanding of the genetic basis of diabetes and related traits, including fasting plasma glucose (FPG). However, the majority of GWASs have been conducted in populations of European ancestry. Thus, it is important to conduct replication analyses in populations with non-European ancestry to identify shared loci associated with FPG across populations. METHODS: We used data collected from non-diabetic unrelated African-American individuals (n = 927) who participated in the Howard University Family Study to attempt to replicate previously published GWASs of FPG. Of the 29 single nucleotide polymorphisms (SNPs) previously reported, we directly tested 20 in this study. In addition to the direct test, we queried a 500 kb window centred on all 29 reported SNPs for local replication of additional markers in linkage disequilibrium (LD). RESULTS: Using direct SNP and LD-based comparisons, we replicated multiple SNPs previously associated with FPG and strongly associated with type 2 diabetes in populations with European ancestry. The replicated SNPs included those in or near TCF7L2, SLC30A8, G6PC2, MTNR1B, DGKB-TMEM195 and GCKR. We also replicated additional variants in LD with the reported SNPs in ZMAT4 and adjacent to IRS1. CONCLUSIONS/INTERPRETATION: We identified multiple GWAS variants for FPG in our cohort of African-Americans. Using an LD-based strategy we also identified SNPs not previously reported, demonstrating the utility of using diverse populations for replication analysis.


Subject(s)
Blood Glucose/genetics , Fasting/blood , Genome-Wide Association Study/methods , Black or African American , Genotype , Humans , Linkage Disequilibrium/genetics , White People
5.
Nat Cell Biol ; 3(9): E207-9, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11533673

ABSTRACT

Separase is a protease that cleaves the bonds between sister chromatids during cell division. Until now, separase was thought to be a somewhat repressed protease, cleaving only a few substrates in a very controlled fashion. New findings in this issue raise the possibility that separase has some of the atavistic impulses that characterize caspases, its more destructive relatives.


Subject(s)
Cell Cycle Proteins/metabolism , Cell Cycle/physiology , Chromatids/metabolism , Endopeptidases , Saccharomyces cerevisiae/physiology , Schizosaccharomyces/physiology , Cell Division , Chromatids/genetics , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins , Schizosaccharomyces/cytology , Schizosaccharomyces/genetics , Separase
6.
Proc Natl Acad Sci U S A ; 98(15): 8270-5, 2001 Jul 17.
Article in English | MEDLINE | ID: mdl-11459963

ABSTRACT

Accurate chromosome segregation requires that replicated sister chromatids are held together until anaphase, when their "cohesion" is dissolved, and they are pulled to opposite spindle poles by microtubules. Establishment of new cohesion between sister chromatids in the next cell cycle is coincident with replication fork passage. Emerging evidence suggests that this temporal coupling is not just a coincident timing of independent events, but rather that the establishment of cohesion is likely to involve the active participation of replication-related activities. These include PCNA, a processivity clamp for some DNA polymerases, Trf4/Pol final sigma (formerly Trf4/Pol kappa), a novel and essential DNA polymerase, and a modified Replication Factor C clamp--loader complex. Here we describe recent advances in how cohesion establishment is linked to replication, highlight important unanswered questions in this new field, and describe a "polymerase switch" model for how cohesion establishment is coupled to replication fork progression. Building the bridges between newly synthesized sister chromatids appears to be a fundamental but previously unrecognized function of the eukaryotic replication machinery.


Subject(s)
Chondroitin Sulfate Proteoglycans , Chromatids , DNA Replication , Nuclear Proteins , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae/genetics , Binding Sites , Catalysis , Cell Cycle Proteins/metabolism , Chromosomal Proteins, Non-Histone/metabolism , DNA Polymerase III/metabolism , DNA-Directed DNA Polymerase/metabolism , Fungal Proteins/metabolism , Humans , S Phase
7.
Cell Biochem Biophys ; 35(3): 289-301, 2001.
Article in English | MEDLINE | ID: mdl-11894848

ABSTRACT

Replicated sister chromatids are held together from their synthesis in S phase to their separation in anaphase. The process of sister chromatid cohesion is essential for the proper segregation of chromosomes in eukaryotic cells. Recent studies in Saccharomyces cerevisiae have advanced our understanding of how sister chromatid cohesion is established, maintained, and dissolved during the cell cycle. Historical observations have suggested that establishment of cohesion is roughly coincident with replication fork passage. Emerging evidence now indicates that replication fork components, such as PCNA, a novel DNA polymerase, Trf4p/Pol sigma (formerly Trf4p/Pol kappa), and a modified clamp-loader complex, actively participate in the process of the cohesion establishment. Here, we review the molecular events in the chromosome cycle with respect to cohesion. Failure of sister chromatid cohesion results in the aneuploidy characteristic of many birth defects and tumors in humans.


Subject(s)
Chromosomes/ultrastructure , DNA Replication , Nuclear Proteins , Saccharomyces cerevisiae Proteins , Sister Chromatid Exchange , Anaphase , Chromosomal Proteins, Non-Histone/metabolism , DNA , DNA Polymerase III/metabolism , DNA-Directed DNA Polymerase/metabolism , Humans , S Phase , Saccharomyces cerevisiae
8.
Science ; 289(5480): 774-9, 2000 Aug 04.
Article in English | MEDLINE | ID: mdl-10926539

ABSTRACT

Establishment of cohesion between sister chromatids is coupled to replication fork passage through an unknown mechanism. Here we report that TRF4, an evolutionarily conserved gene necessary for chromosome segregation, encodes a DNA polymerase with beta-polymerase-like properties. A double mutant in the redundant homologs, TRF4 and TRF5, is unable to complete S phase, whereas a trf4 single mutant completes a presumably defective S phase that results in a failure of cohesion between the replicated sister chromatids. This suggests that TRFs are a key link in the coordination between DNA replication and sister chromatid cohesion. Trf4 and Trf5 represent the fourth class of essential nuclear DNA polymerases (designated DNA polymerase kappa) in Saccharomyces cerevisiae and probably in all eukaryotes.


Subject(s)
Chromatids/metabolism , Chromosomal Proteins, Non-Histone/metabolism , DNA Replication , DNA-Directed DNA Polymerase/metabolism , Nuclear Proteins , S Phase , Saccharomyces cerevisiae Proteins , Chromosomal Proteins, Non-Histone/genetics , DNA Primers/metabolism , DNA-Directed DNA Polymerase/genetics , Enzyme Inhibitors/pharmacology , Fungal Proteins/genetics , Fungal Proteins/metabolism , Humans , In Situ Hybridization, Fluorescence , Mutagenesis, Site-Directed , Mutation , Nucleic Acid Synthesis Inhibitors , Oligodeoxyribonucleotides/metabolism , Recombinant Proteins/metabolism , Saccharomyces cerevisiae/enzymology , Templates, Genetic
9.
J Biol Chem ; 274(11): 7302-8, 1999 Mar 12.
Article in English | MEDLINE | ID: mdl-10066793

ABSTRACT

Camptothecin is an antitumor agent that kills cells by converting DNA topoisomerase I into a DNA-damaging poison. Although camptothecin derivatives are now being used to treat tumors in a variety of clinical protocols, the cellular factors that influence sensitivity to the drug are only beginning to be understood. We report here that two genes required for sister chromatid cohesion, TRF4 and MCD1/SCC1, are also required to repair camptothecin-mediated damage to DNA. The hypersensitivity to camptothecin in the trf4 mutant does not result from elevated expression of DNA topoisomerase I. We show that Trf4 is a nuclear protein whose expression is cell cycle-regulated at a post-transcriptional level. Suppression of camptothecin hypersensitivity in the trf4 mutant by gene overexpression resulted in the isolation of three genes: another member of the TRF4 gene family, TRF5, and two genes that may influence higher order chromosome structure, ZDS1 and ZDS2. We have isolated and sequenced two human TRF4 family members, hTRF4-1 and hTRF4-2. The hTRF4-1 gene maps to chromosome 5p15, a region of frequent copy number alteration in several tumor types. The evolutionary conservation of TRF4 suggests that it may also influence mammalian cell sensitivity to camptothecin.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Camptothecin/pharmacology , Chromosomal Proteins, Non-Histone/genetics , DNA Topoisomerases, Type I/metabolism , DNA-Directed DNA Polymerase , Enzyme Inhibitors/pharmacology , Nuclear Proteins , Saccharomyces cerevisiae Proteins , Amino Acid Sequence , Cell Nucleus/metabolism , Chromosomal Proteins, Non-Histone/metabolism , Chromosome Mapping , DNA Repair , Humans , Molecular Sequence Data , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/genetics , Sequence Homology, Amino Acid , Sister Chromatid Exchange
10.
Genes Dev ; 10(20): 2564-76, 1996 Oct 15.
Article in English | MEDLINE | ID: mdl-8895658

ABSTRACT

DNA topoisomerase I (topo I) is known to participate in the process of DNA replication, but is not essential in Saccharomyces cerevisiae. The TRF4 gene is also nonessential and was identified in a screen for mutations that are inviable in combination with a top1 null mutation. Here we report the surprising finding that a top1 trf4-ts double mutant is defective in the mitotic events of chromosome condensation, spindle elongation, and nuclear segregation, but not in DNA replication. Direct examination of rDNA-containing mitotic chromosomes demonstrates that a top1 trf4-ts mutant fails both to establish and to maintain chromosome condensation in the rDNA at mitosis. We show that the Trf4p associates physically with both Smclp and Smc2p, the S. cerevisiae homologs of Xenopus proteins that are required for mitotic chromosome condensation in vitro. The defect in the top1 trf4-ts mutant is sensed by the MAD1-dependent spindle assembly checkpoint but not by the RAD9-dependent DNA damage checkpoint, further supporting the notion that chromosome structure influences spindle assembly. These data indicate that TOP1 (encoding topo I) and TRF4 participate in overlapping or dependent steps in mitotic chromosome condensation and serve to define a previously unrecognized biological function of topo I.


Subject(s)
Chromosomal Proteins, Non-Histone , DNA Topoisomerases, Type I/metabolism , DNA, Ribosomal , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae/enzymology , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Cell Nucleus , Centromere , Chromosomes , DNA Topoisomerases, Type I/genetics , Fungal Proteins/genetics , Fungal Proteins/metabolism , Mitosis , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Plasmids , Saccharomyces cerevisiae/genetics , Signal Transduction , Spindle Apparatus/physiology
11.
Genomics ; 36(1): 151-6, 1996 Aug 15.
Article in English | MEDLINE | ID: mdl-8812426

ABSTRACT

We report here the complete cDNA sequence, genomic mapping, and immunolocalization of the first human member of the protein kinase C inhibitor (PKCI-1) gene family. The predicted human protein (hPKCI-1) is 96% identical to bovine and 53% identical to maize members, indicating the great evolutionary conservation of this protein family. The hPKCI-1 gene (HGMV-approved symbol PRKCNH1) maps to human chromosome 5q31.2 by fluorescence in situ hybridization. Indirect immunofluorescence shows that hPKCI-1 localizes to cytoskeletal structures in the cytoplasm of a human fibroblast cell line and is largely excluded from the nucleus. The cytoplasmic localization of hPKCI-1 is consistent with a postulated role in mediating a membrane-derived signal in response to ionizing radiation.


Subject(s)
Chromosomes, Human, Pair 5/genetics , Genes/genetics , Nerve Tissue Proteins/genetics , Protein Kinase C/antagonists & inhibitors , Amino Acid Sequence , Base Sequence , Cell Line, Transformed , Chromosome Mapping , Cloning, Molecular , Cytoplasm/chemistry , Cytoskeleton/chemistry , Enzyme Inhibitors , Fibroblasts , Humans , Molecular Sequence Data , Nerve Tissue Proteins/analysis , Recombinant Fusion Proteins/analysis , Sequence Homology, Amino Acid
12.
Nucleic Acids Res ; 24(12): 2404-10, 1996 Jun 15.
Article in English | MEDLINE | ID: mdl-8710513

ABSTRACT

We recently reported the identification of a gene, TRF4 (for DNA topoisomerase related function), in a screen for mutations that are synthetically lethal with mutations in DNA topoisomerase I (top1). Here we describe the isolation of a second member of the TRF4 gene family, TRF5. Overexpression of TRF5 complements the inviability of top1 trf4 double mutants. The predicted Trf5 protein is 55% identical and 72% similar to Trf4p. As with Trf4p, a region of Trf5p is homologous to the catalytically dispensable N-terminus of Top1p. The TRF4/5 function is essential as trf4 trf5 double mutants are inviable. A trf4 (ts) trf5 double mutant is hypersensitive to the anti-microtubule agent thiabendazole at a semi-permissive temperature, suggesting that TRF4/5 function is required at the time of mitosis. Examination of nuclear morphology in a trf4 (ts) trf5 mutant at a restrictive temperature reveals the presence of many cells undergoing aberrant nuclear division, as well as many anucleate cells, demonstrating that the TRF4/5 function is required for proper mitosis. Database searches reveal the existence of probable Schizosaccharomyces pombe and human homologs of Trf4p, indicating that TRF4 is the canonical member of a gene family that is highly conserved evolutionarily.


Subject(s)
Cell Nucleus/physiology , DNA Topoisomerases, Type I/genetics , Saccharomyces cerevisiae/enzymology , Amino Acid Sequence , DNA Topoisomerases, Type I/metabolism , Gene Expression , Genetic Complementation Test , Genome, Fungal , Humans , Mitosis , Molecular Sequence Data , Multigene Family , Mutation , Saccharomyces cerevisiae/genetics , Sequence Homology, Amino Acid
13.
Genetics ; 141(2): 465-79, 1995 Oct.
Article in English | MEDLINE | ID: mdl-8647385

ABSTRACT

Despite evidence that DNA topoisomerase I is required to relieve torsional stress during DNA replication and transcription, yeast strains with a top1 null mutation are viable and display no gross defects in DNA or RNA synthesis, possibly because other proteins provide overlapping functions. We isolated mutants whose inviablility or growth defect is relieved when TOP1 is expressed [trf mutants (topoisomerase one-requiring function)]. The TRF genes define at least four complementation groups. TRF3 is allelic to TOP2. TRF1 is allelic to HPR1, previously shown to be homologous to TOP1 over two short regions. TRF4 encodes a novel 584-amino acid protein with homology to the N-terminus of Saccharomyces cerevisiae topo I. Like top1 mutants, trf4 mutants have elevated rDNA recombination and fail to shut off RNA polymerase II transcription in stationary phase. trf4 null mutants are cs for viability, display reduced expression of GAL1 and Cell Cycle Box UAS::LacZ fusions, and are inviable in combination with trfI null mutants, indicating that both proteins may share a common function with DNA topoisomerase I. The existence of multiple TRF complementation groups suggests that not all biological functions of topo I can be carried out by topo II.


Subject(s)
DNA Topoisomerases, Type I/genetics , DNA Topoisomerases, Type I/metabolism , Saccharomyces cerevisiae/genetics , Alleles , Amino Acid Sequence , Base Sequence , Crosses, Genetic , DNA Replication , DNA Topoisomerases, Type II/metabolism , Genes, Fungal , Genes, Lethal , Genetic Complementation Test , Genotype , Molecular Sequence Data , Mutagenesis , Plasmids , Recombination, Genetic , Saccharomyces cerevisiae/enzymology , Sequence Homology, Amino Acid , Transcription, Genetic
14.
Proc Natl Acad Sci U S A ; 92(17): 7824-8, 1995 Aug 15.
Article in English | MEDLINE | ID: mdl-7644499

ABSTRACT

Ataxia-telangiectasia (AT) is an autosomal recessive human genetic disease characterized by immunological, neurological, and developmental defects and an increased risk of cancer. Cells from individuals with AT show sensitivity to ionizing radiation, elevated recombination, cell cycle abnormalities, and aberrant cytoskeletal organization. The molecular basis of the defect is unknown. A candidate AT gene (ATDC) was isolated on the basis of its ability to complement the ionizing radiation sensitivity of AT group D fibroblasts. Whether ATDC is mutated in any AT patients is not known. We have found that the ATDC protein physically interacts with the intermediate-filament protein vimentin, which is a protein kinase C substrate and colocalizing protein, and with an inhibitor of protein kinase C, hPKCI-1. Indirect immunofluorescence analysis of cultured cells transfected with a plasmid encoding an epitope-tagged ATDC protein localizes the protein to vimentin filaments. We suggest that the ATDC and hPKCI-1 proteins may be components of a signal transduction pathway that is induced by ionizing radiation and mediated by protein kinase C.


Subject(s)
Ataxia Telangiectasia/genetics , DNA-Binding Proteins/metabolism , Protein Kinase C/metabolism , Vimentin/metabolism , Amino Acid Sequence , Animals , Ataxia Telangiectasia/metabolism , Binding Sites , Breast Neoplasms , Cattle , Cell Line , Cell Line, Transformed , Cells, Cultured , Chromatography, Affinity , DNA-Binding Proteins/genetics , DNA-Binding Proteins/isolation & purification , Fibroblasts/metabolism , Fibroblasts/radiation effects , Genetic Complementation Test , Humans , Leucine Zippers , Molecular Sequence Data , Protein Kinase C/antagonists & inhibitors , Protein Kinase C/chemistry , Radiation, Ionizing , Sequence Homology, Amino Acid , Transcription Factors , Tumor Cells, Cultured , Vimentin/chemistry , Zinc Fingers
15.
Genes Chromosomes Cancer ; 13(3): 175-85, 1995 Jul.
Article in English | MEDLINE | ID: mdl-7669737

ABSTRACT

Identification of the genetic alterations that occur in tumors is an important approach to understanding tumorigenesis. We have used comparative genomic hybridization (CGH), a novel molecular cytogenetic method, to identify the gross DNA copy number changes that commonly occur in small cell lung cancer (SCLC). We analyzed ten SCLC tumors (seven primary tumors and three metastases) from eight patients. We found frequent increases in DNA copy number on chromosome arms 5p, 8q, 3q, and Xq and frequent decreases in copy number on chromosome arms 3p, 17p, 5q, 8p, 13q, and 4p. The increase in copy number at 8q24 (MYC) and decreases at 17p13 (TP53), 13q14 (RB), and 3p have previously been identified in SCLC with other methods. Many of the other regions in which we detected common copy number changes have not been reported to be regions of common alteration in SCLC tumors. Comparison of copy number changes between a primary tumor and a metastasis from the same patient showed that they were more closely related to each other than to any of the other tumors. The results of direct CGH analysis of SCLC tumors reported here confirm the existence of copy number changes that we identified previously by using cell lines.


Subject(s)
Carcinoma, Small Cell/genetics , Chromosome Aberrations , Lung Neoplasms/genetics , Aged , Chromosome Mapping , Chromosomes, Human, Pair 13 , Chromosomes, Human, Pair 17 , Chromosomes, Human, Pair 18 , Chromosomes, Human, Pair 22 , Chromosomes, Human, Pair 3 , Chromosomes, Human, Pair 5 , Chromosomes, Human, Pair 8 , DNA, Neoplasm/analysis , Female , Humans , Male , Middle Aged , X Chromosome
16.
Cancer Res ; 55(14): 3055-9, 1995 Jul 15.
Article in English | MEDLINE | ID: mdl-7606727

ABSTRACT

We have undertaken a study of DNA copy number changes in head and neck squamous cell carcinomas to identify novel DNA copy number changes and to determine the significance of previous findings of cytogenetic alterations in cultured cells. Comparative genomic hybridization was performed on genomic DNA extracted from ten tumors. A novel copy number gain on chromosome 3q26-27 and a loss of chromosome 3p were found at high frequency (> or = 50% of tumors). Many other novel chromosomal copy number changes were identified but occurred at a lower frequency. In addition, our data confirm that DNA copy number changes that frequently occur in cultured cells, such as loss of chromosome 3p, also occur in tumors. Frequently altered loci may encode oncogenes or tumor suppressor genes involved in head and neck squamous cell carcinoma tumorigenesis.


Subject(s)
Carcinoma, Squamous Cell/genetics , DNA, Neoplasm/genetics , Gene Amplification , Head and Neck Neoplasms/genetics , Aged , Aged, 80 and over , Chromosome Aberrations , Chromosomes, Human, Pair 3 , Female , Genome, Human , Humans , Male , Middle Aged , Nucleic Acid Hybridization
17.
Mol Cell Biol ; 15(3): 1698-708, 1995 Mar.
Article in English | MEDLINE | ID: mdl-7862161

ABSTRACT

The Hpr1 protein has an unknown function, although it contains a region of homology to DNA topoisomerase I. We have found that hpr1 null mutants are defective in the transcription of many physiologically unrelated genes, including GAL1, HO, ADH1, and SUC2, by using a combination of Northern (RNA) blot analysis, primer extension, and upstream activation sequence-lacZ fusions. Many of the genes positively regulated by HPR1 also require SWI1, SWI2-SNF2, SWI3, SNF5, and SNF6. The transcriptional defect at HO and the CCB::lacZ upstream activation sequence in hpr1 mutants is partially suppressed by a deletion of SIN1, which encodes an HMG1p-like protein. Elevated gene dosage of either histones H3 and H4 or H2A and H2B results in a severe growth defect in combination with an hpr1 null mutation. However, increased gene dosage of all four histones simultaneously restores near-normal growth in hpr1 mutants. Altered in vivo Dam methylase sensitivity is observed at two HPR1-dependent promoters (GAL1 and SUC2). Most of the Hpr1 protein present in the cell is in a large complex (10(6) Da) that is distinct from the SWI-SNF protein complex. We propose that HPR1 affects transcription and recombination by altering chromatin structure.


Subject(s)
Fungal Proteins/biosynthesis , Gene Expression Regulation, Fungal , Genes, Fungal , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae/metabolism , Site-Specific DNA-Methyltransferase (Adenine-Specific) , Transcription Factors/biosynthesis , Transcription, Genetic , Base Sequence , Chromatography, Gel , Chromatography, High Pressure Liquid , DNA Primers , Fungal Proteins/genetics , Fungal Proteins/metabolism , Genotype , Methyltransferases/metabolism , Molecular Sequence Data , Nuclear Proteins , Plasmids , Polymerase Chain Reaction , Promoter Regions, Genetic , Recombinant Fusion Proteins/biosynthesis , Saccharomyces cerevisiae/genetics , Sequence Deletion , Suppression, Genetic
18.
Cancer Res ; 55(6): 1227-31, 1995 Mar 15.
Article in English | MEDLINE | ID: mdl-7882313

ABSTRACT

We have found 16 of 28 small cell lung cancers, 17 of 31 non-small cell lung cancers, 2 of 3 carcinoids, and 12 of 14 mesotheliomas that had chromosome 22 cytogenetic abnormalities. To determine whether the neurofibromatosis type 2 (NF2) gene located on chromosome 22 participates in the oncogenesis of these malignancies, we studied DNAs from lung cancer cell lines and mesotheliomas using Southern blot analysis and the single-strand conformation polymorphism (SSCP) technique for mutations covering 8 of the 16 known NF2 exons. We detected 7 mutations in 17 mesotheliomas (41%) within the coding region of NF2 but none in 75 lung cancer cell lines (38 small cell lung cancers, 34 non-small cell lung cancers, and 3 carcinoids). These mutations were found to be somatic when normal tissue was available for testing. Four mesothelioma cell lines had relatively large deletions (approximately 10-50 kilobases) in the NF2 gene detectable by Southern blot analysis. Two mesothelioma cell lines had nonsense mutations at codons 57 and 341, respectively. Another mesothelioma obtained as a specimen directly from a patient, had a 10-base pair microdeletion from nucleotide 1004 to nucleotide 1013 causing a frameshift mutation. These results suggest that the NF2 gene participates in the oncogenesis in a subset of mesotheliomas but not in lung cancers.


Subject(s)
Genes, Neurofibromatosis 2 , Lung Neoplasms/genetics , Mesothelioma/genetics , Mutation , Base Sequence , Chromosomes, Human, Pair 22 , DNA-Binding Proteins/genetics , Gene Deletion , Genes, Tumor Suppressor , Humans , Molecular Sequence Data , Transcription Factors/genetics , Tumor Cells, Cultured , WT1 Proteins
19.
Int J Radiat Biol ; 66(6 Suppl): S77-84, 1994 Dec.
Article in English | MEDLINE | ID: mdl-7836856

ABSTRACT

Nucleotide sequence analysis of a candidate gene for A-T group D (ATDC) demonstrated that it is related to a group of proteins that contain both zinc finger and leucine zipper motifs. The presence of a leucine zipper suggested that this protein might form homodimers, and this was confirmed by means of the two-hybrid system in yeast. The activity of some proteins that form homodimers can be effectively eliminated by overexpression of inactive forms of the protein that bind to the wild-type protein to create a dominant negative phenotype. An ATDC cDNA containing a 37 amino acid deletion in the zinc finger region (ATDC delta) was therefore transfected into colorectal carcinoma human tumour cells (RKO) to determine whether its expression would produce a response to radiation similar to that seen in A-T cells. RKO cells have been shown to have normal radiosensitivity and cell cycle regulation and, therefore, seemed ideal for this study. Despite the fact that the A-T gene has been found to be important in the radiation damage response, no ATDC mRNA transcripts were detectable in the RKO cell line. In addition, the RKO subclones expressing the ATDC delta mRNA showed no change in radiosensitivity or cell cycle regulation. These results do not support the conclusion that ATDC is an A-T gene, and suggest that the ATDC protein acts indirectly to suppress radiosensitivity in A-T cells.


Subject(s)
Ataxia Telangiectasia/genetics , Radiation Tolerance/physiology , Amino Acid Sequence , Ataxia Telangiectasia/physiopathology , Base Sequence , Cell Cycle/physiology , Cell Line, Transformed , Cloning, Molecular , Colorectal Neoplasms/genetics , DNA Probes , DNA-Binding Proteins/genetics , Fibroblasts/physiology , Fibroblasts/radiation effects , Gene Expression/radiation effects , Humans , Leucine Zippers/genetics , Molecular Sequence Data , Phenotype , RNA, Messenger/analysis , Transcription Factors , Tumor Cells, Cultured/radiation effects , Zinc Fingers/genetics
20.
Cancer Res ; 54(19): 5086-91, 1994 Oct 01.
Article in English | MEDLINE | ID: mdl-7923122

ABSTRACT

We have performed a comprehensive analysis of the DNA copy number changes that occur in 18 small cell lung carcinoma cell lines using comparative genomic hybridization (Kallioniemi et al., Science (Washington DC). 258: 818-821, 1992). DNA copy number abnormalities detected in this study include previously identified increases at 1p22-32 (L-myc), 2p24-25 (N-myc), and 8q24 (c-myc) and decreases at 17p13 (p53), 13q14 (RB), and 3p. In addition, novel DNA copy number increases were detected at 5p, 1q24, and Xq26, and novel decreases were found at 22q12.1-13.1, 10q26, and 16p11.2. Many of the most common DNA copy number changes revealed are at loci not previously recognized to be important in small cell lung cancer. In addition, a number of the DNA copy number changes, including increases at 1p22-32, 2p24-25, and 3q22-25 and a decrease on 18p, were found to occur preferentially in small cell lung carcinoma lines of the "variant" phenotype. This correlation suggests that genes may reside at these loci whose overexpression or inactivation contributes to the radiation resistance or aggressive growth phenotypes characteristic of this subtype of small cell lung carcinoma.


Subject(s)
Carcinoma, Small Cell/genetics , Lung Neoplasms/genetics , DNA, Neoplasm/analysis , Female , Genes, myc , Humans , Male , Nucleic Acid Hybridization , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-myb , Radiation Tolerance , Tumor Cells, Cultured
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