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1.
Genome Res ; 21(4): 535-44, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21383316

RESUMO

Insertions occur when a segment of one chromosome is translocated and inserted into a new region of the same chromosome or a non-homologous chromosome. We report 71 cases with unbalanced insertions identified using array CGH and FISH in 4909 cases referred to our laboratory for array CGH and found to have copy-number abnormalities. Although the majority of insertions were non-recurrent, several recurrent unbalanced insertions were detected, including three der(Y)ins(Y;18)(q?11.2;p11.32p11.32)pat inherited from parents carrying an unbalanced insertion. The clinical significance of these recurrent rearrangements is unclear, although the small size, limited gene content, and inheritance pattern of each suggests that the phenotypic consequences may be benign. Cryptic, submicroscopic duplications were observed at or near the insertion sites in two patients, further confounding the clinical interpretation of these insertions. Using FISH, linear amplification, and array CGH, we identified a 126-kb duplicated region from 19p13.3 inserted into MECP2 at Xq28 in a patient with symptoms of Rett syndrome. Our results demonstrate that although the interpretation of most non-recurrent insertions is unclear without high-resolution insertion site characterization, the potential for an otherwise benign duplication to result in a clinically relevant outcome through the disruption of a gene necessitates the use of FISH to determine whether copy-number gains detected by array CGH represent tandem duplications or unbalanced insertions. Further follow-up testing using techniques such as linear amplification or sequencing should be used to determine gene involvement at the insertion site after FISH has identified the presence of an insertion.


Assuntos
Hibridização Genômica Comparativa , Variações do Número de Cópias de DNA/genética , Hibridização in Situ Fluorescente , Mutagênese Insercional/genética , Translocação Genética , Sequência de Bases , Pontos de Quebra do Cromossomo , Cromossomos Humanos/genética , Feminino , Ordem dos Genes , Humanos , Masculino , Dados de Sequência Molecular , Síndrome de Rett/genética , Alinhamento de Sequência
2.
Fetal Diagn Ther ; 36(3): 231-41, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25115231

RESUMO

BACKGROUND: While microarray testing can identify chromosomal abnormalities missed by karyotyping, its prenatal use is often avoided in low-risk pregnancies due to the possible identification of variants of uncertain significance (VOUS). METHODS: We tested 2,970 prenatal samples of all referral indications using a rapid BACs-on-Beads-based assay with probes for sex chromosomes, common autosomal aneuploidies, and 20 microdeletion/microduplication syndromes, designed as an alternative to microarray in low-risk pregnancies and an alternative to rapid aneuploidy testing in pregnancies also undergoing microarray analysis. RESULTS: Interpretable results were obtained in 2,940 cases (99.0%), with 89% receiving results in 1 day. Aneuploidies were detected in 7.3% and partial chromosome abnormalities in 0.45% (n = 13), including 5 referred for maternal age, abnormal maternal serum screen, or isolated ultrasound markers. The added detection above karyotype was 1 in 745 in lower-risk cases with normal ultrasounds or isolated ultrasound markers/increased nuchal measurements and 1 in 165 for fetuses with structural/growth abnormalities. Neither false negatives nor false positives were found within test limitations. Female polyploidy could not be detected, while polyploidies with Y chromosomes were suspected and confirmed through additional analysis. CONCLUSION: When combined with karyotyping, this assay provides increased interrogation of specific chromosomal regions, while limiting VOUS identification.


Assuntos
Aneuploidia , Duplicação Cromossômica , Técnicas de Diagnóstico Molecular/estatística & dados numéricos , Diagnóstico Pré-Natal/estatística & dados numéricos , Adulto , Análise Citogenética , Feminino , Humanos , Masculino , Gravidez , Estudos Retrospectivos
3.
Neurogenetics ; 14(2): 99-111, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23389741

RESUMO

MEF2C haploinsufficiency syndrome is an emerging neurodevelopmental disorder associated with intellectual disability, autistic features, epilepsy, and abnormal movements. We report 16 new patients with MEF2C haploinsufficiency, including the oldest reported patient with MEF2C deletion at 5q14.3. We detail the neurobehavioral phenotype, epilepsy, and abnormal movements, and compare our subjects with those previously reported in the literature. We also investigate Mef2c expression in the developing mouse forebrain. A spectrum of neurofunctional deficits emerges, with hyperkinesis a consistent finding. Epilepsy varied from absent to severe, and included intractable myoclonic seizures and infantile spasms. Subjects with partial MEF2C deletion were statistically less likely to have epilepsy. Finally, we confirm that Mef2c is present both in dorsal primary neuroblasts and ventral gamma-aminobutyric acid(GABA)ergic interneurons in the forebrain of the developing mouse. Given interactions with several key neurodevelopmental genes such as ARX, FMR1, MECP2, and TBR1, it appears that MEF2C plays a role in several developmental stages of both dorsal and ventral neuronal cell types.


Assuntos
Criança , Epilepsia/genética , Haploinsuficiência/genética , Hipercinese/genética , Interneurônios/metabolismo , Rede Nervosa/crescimento & desenvolvimento , Adolescente , Adulto , Animais , Pré-Escolar , Deficiências do Desenvolvimento/genética , Feminino , Deleção de Genes , Humanos , Lactente , Fatores de Transcrição MEF2/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Fenótipo , Adulto Jovem
4.
Hum Mutat ; 33(4): 728-40, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22290657

RESUMO

SOX5 encodes a transcription factor involved in the regulation of chondrogenesis and the development of the nervous system. Despite its important developmental roles, SOX5 disruption has yet to be associated with human disease. We report one individual with a reciprocal translocation breakpoint within SOX5, eight individuals with intragenic SOX5 deletions (four are apparently de novo and one inherited from an affected parent), and seven individuals with larger 12p12 deletions encompassing SOX5. Common features in these subjects include prominent speech delay, intellectual disability, behavior abnormalities, and dysmorphic features. The phenotypic impact of the deletions may depend on the location of the deletion and, consequently, which of the three major SOX5 protein isoforms are affected. One intragenic deletion, involving only untranslated exons, was present in a more mildly affected subject, was inherited from a healthy parent and grandparent, and is similar to a deletion found in a control cohort. Therefore, some intragenic SOX5 deletions may have minimal phenotypic effect. Based on the location of the deletions in the subjects compared to the controls, the de novo nature of most of these deletions, and the phenotypic similarities among cases, SOX5 appears to be a dosage-sensitive, developmentally important gene.


Assuntos
Transtornos Dismórficos Corporais/genética , Deficiências do Desenvolvimento/genética , Haploinsuficiência , Transtornos do Desenvolvimento da Linguagem/genética , Transtornos Mentais/genética , Fatores de Transcrição SOXD/genética , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Cromossomos Humanos Par 12 , Feminino , Humanos , Masculino
5.
Hum Genet ; 131(1): 145-56, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21800092

RESUMO

Microdeletions of 1q43q44 result in a recognizable clinical disorder characterized by moderate to severe intellectual disability (ID) with limited or no expressive speech, characteristic facial features, hand and foot anomalies, microcephaly (MIC), abnormalities (agenesis/hypogenesis) of the corpus callosum (ACC), and seizures (SZR). Critical regions have been proposed for some of the more prominent features of this disorder such as MIC and ACC, yet conflicting data have prevented precise determination of the causative genes. In this study, the largest of pure interstitial and terminal deletions of 1q43q44 to date, we characterized 22 individuals by high-resolution oligonucleotide microarray-based comparative genomic hybridization. We propose critical regions and candidate genes for the MIC, ACC, and SZR phenotypes associated with this microdeletion syndrome. Three cases with MIC had small overlapping or intragenic deletions of AKT3, an isoform of the protein kinase B family. The deletion of only AKT3 in two cases implicates haploinsufficiency of this gene in the MIC phenotype. Likewise, based on the smallest region of overlap among the affected individuals, we suggest a critical region for ACC that contains ZNF238, a transcriptional and chromatin regulator highly expressed in the developing and adult brain. Finally, we describe a critical region for the SZR phenotype which contains three genes (FAM36A, C1ORF199, and HNRNPU). Although ~90% of cases in this study and in the literature fit these proposed models, the existence of phenotypic variability suggests other mechanisms such as variable expressivity, incomplete penetrance, position effects, or multigenic factors could account for additional complexity in some cases.


Assuntos
Agenesia do Corpo Caloso/genética , Deleção Cromossômica , Cromossomos Humanos Par 1/genética , Genes/fisiologia , Microcefalia/genética , Convulsões/genética , Anormalidades Múltiplas , Adolescente , Agenesia do Corpo Caloso/patologia , Biomarcadores/metabolismo , Criança , Pré-Escolar , Hibridização Genômica Comparativa , Feminino , Humanos , Hibridização in Situ Fluorescente , Lactente , Deficiência Intelectual/genética , Masculino , Microcefalia/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Convulsões/patologia , Síndrome
6.
Genet Med ; 14(5): 508-14, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22241097

RESUMO

PURPOSE: Neurofibromatosis, type 1 (NF1) is an autosomal dominant disorder caused by mutations of the neurofibromin 1 (NF1) gene at 17q11.2. Approximately 5% of individuals with NF1 have a 1.4-Mb heterozygous 17q11.2 deletion encompassing NF1, formed through nonallelic homologous recombination (NAHR) between the low-copy repeats that flank this region. NF1 microdeletion syndrome is more severe than NF1 caused by gene mutations, with individuals exhibiting facial dysmorphisms, developmental delay (DD), intellectual disability (ID), and excessive neurofibromas. Although NAHR can also cause reciprocal microduplications, reciprocal NF1 duplications have been previously reported in just one multigenerational family and a second unrelated proband. METHODS: We analyzed the clinical features in seven individuals with NF1 microduplications, identified among 48,817 probands tested in our laboratory by array-based comparative genomic hybridization. RESULTS: The only clinical features present in more than one individual were variable DD/ID, facial dysmorphisms, and seizures. No neurofibromas were present. Three sets of parents were tested: one duplication was apparently de novo, one inherited from an affected mother, and one inherited from a clinically normal father. CONCLUSION: This is the first report comparing the phenotypes of nonrelated individuals with NF1 microduplications. This comparison will allow for further definition of this emerging microduplication syndrome.


Assuntos
Cromossomos Humanos Par 17/genética , Duplicação Gênica , Neurofibromatose 1/diagnóstico , Neurofibromatose 1/genética , Neurofibromina 1/genética , Adolescente , Estudos de Casos e Controles , Criança , Pré-Escolar , Hibridização Genômica Comparativa , Deficiências do Desenvolvimento/genética , Feminino , Genes da Neurofibromatose 1 , Recombinação Homóloga , Humanos , Lactente , Recém-Nascido , Deficiência Intelectual/genética , Masculino , Neurofibroma/genética , Fenótipo , Duplicações Segmentares Genômicas/genética , Deleção de Sequência , Adulto Jovem
7.
Int J Cancer ; 128(12): 2823-32, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-20734393

RESUMO

Conventional chemotherapy is commonly used for advanced stages of bladder cancer with modest success and high morbidity. Identifying markers of resistance will allow clinicians to tailor treatment to a specific patient population. T24-tumorigenic cell line was grown orthotopically in nude mice and monitored using bioluminescence imaging and microcomputed tomography until they developed metastases. Stable sublines were then developed from primary bladder (T24-P), lung (T24-L) and bone (T24-B) tissues. Chromosomal analysis and DNA microarray were used to characterize these sublines. Real-time quantitative polymerase chain reaction and immunohistochemistry were used for validation. Epigenetic modifiers were used to study gene regulation. The cell viability was quantified with MTT assay. Chromosomal analysis revealed multiple alterations in metastatic cell lines compared to T24-P. DNA microarray analysis showed that taxol resistance-associated gene (TRAG) 3 was the most upregulated gene. From real-time quantitative polymerase chain reaction and immunohistochemistry, TRAG3 was significantly higher in T24-L and T24-B than T24-P. TRAG3 gene expression is likely controlled by DNA methylation but not histone acetylation. Interestingly, T24-B and T24-L cells were more resistant than T24-P to treatment with antimicrotubule agents such as docetaxel, paclitaxel and vinblastine. TRAG3 mRNA expression was higher in 20% of patients with ≤ pT2 (n = 10) and 60% of patients with ≥ pT3 (n = 20) compared to normal adjacent tissue (p = 0.05). In addition, the median TRAG3 expression was 6.7-fold higher in ≥ pT3 tumors compared to ≤ pT2 tumors. Knowing the status of TRAG3 expression could help clinicians tailor treatment to a particular patient population that could benefit from treatment, while allocating patients with resistant tumors to new experimental therapies.


Assuntos
Carcinoma de Células de Transição/genética , Proteínas de Neoplasias/genética , Regulação para Cima , Neoplasias da Bexiga Urinária/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Sequência de Bases , Carcinoma de Células de Transição/patologia , Primers do DNA , Feminino , Humanos , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Metástase Neoplásica , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Neoplasias da Bexiga Urinária/patologia
8.
Genet Med ; 13(10): 868-80, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21792059

RESUMO

PURPOSE: : Recently, molecular cytogenetic techniques have identified novel copy number variants in individuals with schizophrenia. However, no large-scale prospective studies have been performed to characterize the broader spectrum of phenotypes associated with such copy number variants in individuals with unexplained physical and intellectual disabilities encountered in a diagnostic setting. METHODS: : We analyzed 38,779 individuals referred to our diagnostic laboratory for microarray testing for the presence of copy number variants encompassing 20 putative schizophrenia susceptibility loci. We also analyzed the indications for study for individuals with copy number variants overlapping those found in six individuals referred for schizophrenia. RESULTS: : After excluding larger gains or losses that encompassed additional genes outside the candidate loci (e.g., whole-arm gains/losses), we identified 1113 individuals with copy number variants encompassing schizophrenia susceptibility loci and 37 individuals with copy number variants overlapping those present in the six individuals referred to our laboratory for schizophrenia. Of these, 1035 had a copy number variant of one of six recurrent loci: 1q21.1, 15q11.2, 15q13.3, 16p11.2, 16p13.11, and 22q11.2. The indications for study for these 1150 individuals were diverse and included developmental delay, intellectual disability, autism spectrum, and multiple congenital anomalies. CONCLUSION: : The results from our study, the largest genotype-first analysis of schizophrenia susceptibility loci to date, suggest that the phenotypic effects of copy number variants associated with schizophrenia are pleiotropic and imply the existence of shared biologic pathways among multiple neurodevelopmental conditions.


Assuntos
Sintomas Comportamentais/genética , Variações do Número de Cópias de DNA , Deficiências do Desenvolvimento/genética , Loci Gênicos , Transtornos do Desenvolvimento da Linguagem/genética , Esquizofrenia/genética , Adolescente , Criança , Pré-Escolar , Deleção Cromossômica , Duplicação Cromossômica , Cromossomos Humanos , Hibridização Genômica Comparativa , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Hereditariedade , Humanos , Lactente , Recém-Nascido , Masculino , Adulto Jovem
9.
Am J Med Genet A ; 155A(8): 1906-16, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21744490

RESUMO

Although copy number changes of 5q31 have been rarely reported, deletions have been associated with some common characteristics, such as short stature, failure to thrive, developmental delay (DD)/intellectual disability (ID), club feet, dislocated hips, and dysmorphic features. We report on three individuals with deletions and two individuals with duplications at 5q31, ranging from 3.6 Mb to 8.1 Mb and 830 kb to 3.4 Mb in size, respectively. All five copy number changes are apparently de novo and involve several genes that are important in developmental pathways, including PITX1, SMAD5, and WNT8A. The individuals with deletions have characteristic features including DD, short stature, club feet, cleft or high palate, dysmorphic features, and skeletal anomalies. Haploinsufficiency of PITX1, a transcription factor important for limb development, is likely the cause for the club feet, skeletal anomalies, and cleft/high palate, while additional genes, including SMAD5 and WNT8A, may also contribute to additional phenotypic features. Two patients with deletions also presented with corneal anomalies. To identify a causative gene for the corneal anomalies, we sequenced candidate genes in a family with apparent autosomal dominant keratoconus with suggestive linkage to 5q31, but no mutations in candidate genes were found. The duplications are smaller than the deletions, and the patients with duplications have nonspecific features. Although development is likely affected by increased dosage of the genes in the region, the developmental disruption appears less severe than that seen with deletion.


Assuntos
Anormalidades Múltiplas/genética , Transtornos Cromossômicos/diagnóstico , Cromossomos Humanos Par 5/genética , Deficiências do Desenvolvimento/genética , Deleção de Genes , Duplicação Gênica , Genes Controladores do Desenvolvimento , Criança , Pré-Escolar , Transtornos Cromossômicos/genética , Hibridização Genômica Comparativa , Feminino , Dosagem de Genes , Ligação Genética , Estudo de Associação Genômica Ampla , Humanos , Recém-Nascido , Ceratocone/genética , Masculino , Fenótipo , Análise de Sequência de DNA
10.
Carcinogenesis ; 31(6): 968-73, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19995795

RESUMO

Basal cell carcinomas (BCCs) have relative genomic stability and relatively benign clinical behavior but whether these two are related causally is unknown. To investigate the effects of introducing genomic instability into murine BCCs, we have compared ionizing radiation-induced tumorigenesis in Ptch1(+/-) mice versus that in Ptch1(+/-) mice carrying mutant Blm alleles. We found that BCCs in Ptch1(+/-) Blm(tm3Brd/tm3Brd) mice had a trend toward greater genomic instability as measured by array comprehensive genomic hybridization and that these mice developed significantly more microscopic BCCs than did Ptch1(+/-) Blm(+/tm3Brd) or Ptch1(+/-) Blm(+/+) mice. The mutant Blm alleles also markedly enhanced the formation of rhabdomyosarcomas (RMSs), another cancer to which Ptch1(+/)(-) mice and PTCH1(+/)(-) (basal cell nevus syndrome) patients are susceptible. Highly recurrent but different copy number changes were associated with the two tumor types and included losses of chromosomes 4 and 10 in all BCCs and gain of chromosome 10 in 80% of RMSs. Loss of chromosome 11 and 13, including the Trp53 and Ptch1 loci, respectively, occurred frequently in BCCs, suggesting tissue-specific selection for genes or pathways that collaborate with Ptch deficiency in tumorigenesis. Despite the quantitative differences, there was no dramatic qualititative difference in the BCC or RMS tumors associated with the mutant Blm genotype.


Assuntos
Carcinoma Basocelular/genética , RecQ Helicases/genética , Rabdomiossarcoma/genética , Neoplasias Cutâneas/genética , Alelos , Animais , Carcinoma Basocelular/patologia , Camundongos , Rabdomiossarcoma/patologia
11.
Hum Mol Genet ; 17(14): 2172-80, 2008 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-18411254

RESUMO

Roberts syndrome/SC phocomelia (RBS) is an autosomal recessive disorder with growth retardation, craniofacial abnormalities and limb reduction. Cellular alterations in RBS include lack of cohesion at the heterochromatic regions around centromeres and the long arm of the Y chromosome, reduced growth capacity, and hypersensitivity to DNA damaging agents. RBS is caused by mutations in ESCO2, which encodes a protein belonging to the highly conserved Eco1/Ctf7 family of acetyltransferases that is involved in regulating sister chromatid cohesion. We identified 10 new mutations expanding the number to 26 known ESCO2 mutations. We observed that these mutations result in complete or partial loss of the acetyltransferase domain except for the only missense mutation that occurs in this domain (c.1615T>G, W539G). To investigate the mechanism underlying RBS, we analyzed ESCO2 mutations for their effect on enzymatic activity and cellular phenotype. We found that ESCO2 W539G results in loss of autoacetyltransferase activity. The cellular phenotype produced by this mutation causes cohesion defects, proliferation capacity reduction and mitomycin C sensitivity equivalent to those produced by frameshift and nonsense mutations associated with decreased levels of mRNA and absence of protein. We found decreased proliferation capacity in RBS cell lines associated with cell death, but not with increased cell cycle duration, which could be a factor in the development of phocomelia and cleft palate in RBS. In summary, we provide the first evidence that loss of acetyltransferase activity contributes to the pathogenesis of RBS, underscoring the essential role of the enzymatic activity of the Eco1p family of proteins.


Assuntos
Acetiltransferases/genética , Proteínas Cromossômicas não Histona/genética , Ectromelia/enzimologia , Ectromelia/genética , Mutação , Síndrome de Pierre Robin/enzimologia , Síndrome de Pierre Robin/genética , Acetiltransferases/metabolismo , Ciclo Celular , Proliferação de Células , Células Cultivadas , Proteínas Cromossômicas não Histona/metabolismo , Códon sem Sentido , Feminino , Mutação da Fase de Leitura , Humanos , Masculino , Fenótipo
13.
DNA Repair (Amst) ; 6(1): 100-14, 2007 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-17079196

RESUMO

The disease Xeroderma Pigmentosum (XP) is genetically heterogeneous and defined by pathogenic variants (formerly termed mutations) in any of eight different genes. Pathogenic variants in the XPC gene are the most commonly observed in US patients. Moreover, pathogenic variants in just four of the genes, XPA, XPC, XPD/ERCC2 and XPV/POLH account for 91% of all XP cases worldwide. In the current study, we describe the clinical, histopathologic, molecular genetic, and pathophysiological features of a 19-year-old female patient clinically diagnosed with XP as an infant. Analysis of archival material reveals a novel variation of a 13 base pair deletion in XPC exon 14 and a previously reported A>C missense pathogenic variant in the proximal splice site for XPC exon 6. Both variations induce frameshifts most likely leading to a truncated XPC protein product. Quantitative RT-PCR also revealed reduced mRNA levels in the archived specimen. Analysis of the XPA, XPD/ERCC2 and XPV/POLH genes in the current specimen failed to reveal pathologic variants. All previously reported pathogenic variants, polymorphisms and known amino acid changes for the XPC gene are compiled and described in the current nomenclature. Given the relative ease of screening for genetic variation and the potential role for such variation in human disease, a proposal for screening appropriate archival materials for alterations in the four most prevalent XP genes is presented.


Assuntos
Proteínas de Ligação a DNA/genética , Variação Genética , Xeroderma Pigmentoso/diagnóstico , Adulto , Arquivos , Reparo do DNA , Feminino , Humanos , Mutação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Xeroderma Pigmentoso/genética , Proteína de Xeroderma Pigmentoso Grupo A/genética , Proteína Grupo D do Xeroderma Pigmentoso/genética
14.
DNA Repair (Amst) ; 6(1): 115-20, 2007 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-17084680

RESUMO

Xeroderma pigmentosum (XP) genetic complementation group C (XP-C) is the most common form of the disease worldwide. Thirty-four distinct genetic defects have been identified in 45 XP-C patients. Further identification of such defects and the frequency of their occurrence offers the potential of generating diagnostic and prognostic molecular screening panels. Archival material (such as formalin-fixed paraffin embedded skin) may be useful for the identification of novel genetic variations and for documenting the frequency of individual genetic defects in patients who are no longer available for study. However, the use of archival material precludes direct analysis of changes in the mRNA resulting from genomic changes. The serendipitous reacquisition of an XP individual in whom genetic defects were previously characterized in archival material allowed confirmation of the defects as well as a direct analysis of the consequences of these defects on mRNA, mRNA expression and on cellular phenotypes.


Assuntos
Proteínas de Ligação a DNA/genética , Neoplasias Cutâneas/genética , Xeroderma Pigmentoso/genética , Sobrevivência Celular/genética , Sobrevivência Celular/efeitos da radiação , Células Cultivadas , Reparo do DNA , Fibroblastos/metabolismo , Humanos , Pele/metabolismo , Neoplasias Cutâneas/patologia , Raios Ultravioleta , Xeroderma Pigmentoso/patologia
15.
Curr Opin Genet Dev ; 14(1): 5-10, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15108798

RESUMO

The field of DNA damage responsiveness in general, and the consequences of endogenous and exogenous base damage in DNA, in particular, has made new and exciting contributions to our increasing understanding of the initiation and progression of neoplasia in humans. This article presents some of the highlights in this area of investigation, with a particular emphasis on DNA repair, the tolerance of DNA damage and its contribution to mutagenesis, and DNA damage checkpoint regulation.


Assuntos
Dano ao DNA/genética , Reparo do DNA/genética , Mutagênese/genética , Neoplasias/genética , Bacteriocinas/genética , Proteínas de Ligação a DNA/genética , DNA Polimerase Dirigida por DNA/genética , Anemia de Fanconi/genética , Genes cdc/fisiologia , Humanos , Mutagênese/fisiologia , Rad51 Recombinase
16.
Adv Exp Med Biol ; 637: 65-82, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19181112

RESUMO

ERCC4 is the gene mutated in XPF cells and also in rodent cells representing the mutant complementation groups ERCC4 and ERCC 11. The protein functions principally as a complex with ERCC1 in a diversity of biological pathways that include NER, ICL repair, telomere maintenance and immunoglobulin switching. Sorting out these roles is an exciting and challenging problem and many important questions remain to be answered. The ERCC1/ERCC4 complex is conserved across most species presenting an opportunity to examine some functions in model organisms where mutants can be more readily generated and phenotypes more quickly assessed.


Assuntos
Reparo do DNA , Proteínas de Ligação a DNA/fisiologia , Endonucleases/fisiologia , Animais , Modelos Animais de Doenças , Humanos
17.
DNA Repair (Amst) ; 5(7): 868-72, 2006 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-16762604

RESUMO

Two recent articles suggest new roles for the TERF2-XPF complex (a.k.a. TRF2-XPF) in the recognition/repair of DNA damage at non-telomeric chromosomal locations (i.e. "Caught in the Middle"). These new roles for proteins typically ascribed functions at the ends of chromosomes are proposed to be very early events of DNA damage response (i.e. Beginnings from the End). Our previous understanding of a role for the TERF2-XPF complex in the maintenance of chromosome stability included the preservation of telomere length by "suppression" of the recognition of chromosome ends as breaks. One recent paper demonstrates that TERF2 also functions at non-telomeric sites of DNA damage, and does so prior to initiation of the ATM signaling cascade. A second paper goes on to demonstrate that overexpression of TERF2 produces mouse phenotypes similar to those associated with xeroderma pigmentosum, such as cellular hypersensitivity to UV radiation and DNA crosslinking agents, and telomere shortening and chromosome instability in response to DNA damage. Moreover, data are presented illustrating that these abnormal responses are not seen in an XPF(-/-) background, consistent with a dependency on XPF. Interestingly, both manuscripts focus on events that transpire in response to exogenous DNA damage. Here, we review these exciting findings that suggest new roles for the TERF2-XPF complex and point out several questions that remain to be addressed.


Assuntos
Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , Proteína 2 de Ligação a Repetições Teloméricas/metabolismo , Animais , Dano ao DNA , Proteínas de Ligação a DNA/genética , Humanos , Camundongos , Camundongos Mutantes , Modelos Biológicos , Proteína 2 de Ligação a Repetições Teloméricas/genética
18.
N Engl J Med ; 348(19): 1855-65, 2003 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-12736278

RESUMO

BACKGROUND: Gynecomastia of prepubertal onset may result from increased estrogen owing to excessive aromatase activity in extraglandular tissues. A gene in chromosome 15q21.2 encodes aromatase, the key enzyme for estrogen biosynthesis. Several physiologic tissue-specific promoters regulate the expression of aromatase, giving rise to messenger RNA (mRNA) species with an identical coding region but tissue-specific 5'-untranslated regions in placenta, gonads, brain, fat, and skin. METHODS: We studied skin, fat, and blood samples from a 36-year-old man, his 7-year-old son, and an unrelated 17-year-old boy with severe gynecomastia of prepubertal onset and hypogonadotropic hypogonadism caused by elevated estrogen levels. RESULTS: Aromatase activity and mRNA levels in fat and skin and whole-body aromatization of androstenedione were severely elevated. Treatment with an aromatase inhibitor decreased serum estrogen levels and normalized gonadotropin and testosterone levels. The 5'-untranslated regions of aromatase mRNA contained the same sequence (FLJ) in the father and son and another sequence (TMOD3) in the unrelated boy; neither sequence was found in control subjects. These 5'-untranslated regions normally make up the first exons of two ubiquitously expressed genes clustered in chromosome 15q21.2-3 in the following order (from telomere to centromere): FLJ, TMOD3, and aromatase. The aromatase gene is normally transcribed in the direction opposite to that of TMOD3 and FLJ. Two distinct heterozygous inversions reversed the direction of the TMOD3 or FLJ promoter in the patients. CONCLUSIONS: Heterozygous inversions in chromosome 15q21.2-3, which caused the coding region of the aromatase gene to lie adjacent to constitutively active cryptic promoters that normally transcribe other genes, resulted in severe estrogen excess owing to the overexpression of aromatase in many tissues.


Assuntos
Aromatase/genética , Estradiol/sangue , Estrona/sangue , Ginecomastia/genética , Mutação , Tecido Adiposo/enzimologia , Adolescente , Adulto , Anastrozol , Androstenodiona/sangue , Androstenodiona/metabolismo , Aromatase/metabolismo , Inibidores da Aromatase , Sequência de Bases , Criança , Mapeamento Cromossômico , Cromossomos Humanos Par 15/genética , Dexametasona/farmacologia , Inibidores Enzimáticos/farmacologia , Fibroblastos/enzimologia , Glucocorticoides/farmacologia , Ginecomastia/enzimologia , Humanos , Masculino , Dados de Sequência Molecular , Nitrilas/farmacologia , Regiões Promotoras Genéticas/genética , RNA Mensageiro/metabolismo , Transcrição Gênica , Triazóis/farmacologia
19.
DNA Repair (Amst) ; 2(12): 1387-404, 2003 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-14642567

RESUMO

Independent mouse models for Bloom syndrome (BS) exist, each thought to disrupt Blm gene function. However, animals bearing these alleles exhibit distinct phenotypes. Blm(tm1Ches) and Blm(tm1Grdn) homozygous mutant animals exhibit embryonic lethality while in another, Blm(tm3Brd), homozygosity yields viable, fertile animals with a cancer predisposition. Further characterization reveals the Blm(tm3Brd) allele to be a hypomorph, producing a diminished quantity of normal mRNA and protein. The Blm(tm3Brd) allele produces sufficient normal protein to rescue Blm(tm1Ches) lethality. Evaluation of viable animals reveals an inverse correlation between the quantity of Blm protein and the level of chromosome instability and a similar genotypic relationship for tumor predisposition indicating that Blm protein is rate limiting for maintaining genomic stability and the avoidance of tumors.


Assuntos
Adenosina Trifosfatases/metabolismo , Síndrome de Bloom/genética , Instabilidade Cromossômica , DNA Helicases/metabolismo , Desenvolvimento Embrionário e Fetal/genética , Predisposição Genética para Doença , Neoplasias/genética , Animais , Perda do Embrião/genética , Feminino , Marcação de Genes , Masculino , Camundongos , Camundongos Knockout , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RecQ Helicases , Baço/metabolismo , Supressão Genética
20.
Cancer Genet ; 207(7-8): 306-15, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25442074

RESUMO

Cytogenetic alterations are strong outcome prognosticators in uveal melanoma (UVM). Monosomy 3 (-3) and MYC amplification at 8q24 are commonly tested by fluorescence in situ hybridization (FISH). Alternatively, microarray analysis provides whole genome data, detecting partial chromosome loss, loss of heterozygosity (LOH), or abnormalities unrepresented by FISH probes. Nonfixed frozen tissue is conventionally used for microarray analysis but may not always be available. We assessed the feasibility of genomic microarray analysis for high resolution interrogation of UVM using formalin-fixed paraffin-embedded tissue (FFPET) as an alternative to frozen tissue (FZT). Enucleations from 44 patients (clinical trial NCT00952939) yielded sufficient DNA from FFPET (n = 34) and/or frozen tissue (n = 41) for comparative genomic hybridization and select single nucleotide polymorphism analysis (CGH/SNP) on Roche-NimbleGen OncoChip arrays. CEP3 FISH analysis was performed on matched cytology ThinPrep material. CGH/SNP analysis was successful in 30 of 34 FFPET and 41 of 41 FZT samples. Of 27 paired FFPET/FZT samples, 26 (96.3%) were concordant for at least four of six major recurrent abnormalities (-3, +8q, -1p, +6p, -6q, -8p), and 25 of 27 (92.6%) were concordant for -3. Results of CGH/SNP were concordant with the CEP3 FISH results in 27 of 30 (90%) FFPET and 38 of 41 (92.6%) FZT cases; partial -3q was detected in two CEP3 FISH-negative cases and whole chromosome 3, 4, and 6 SNP-LOH in one case. CGH detection of -3, +8q, -8p on FFPET and FZT showed significant correlation with the clinical outcome measures (metastasis development, time to progression, survival). Results of the UVM genotyping by CGH/SNP on FFPET are highly concordant with those of the FZT analysis and with those of the CEP3 FISH analysis, and therefore CGH/SNP is a practical method for UVM prognostication. Genome-wide coverage provides additional data with potential relevance to UVM biology, diagnosis, and prognosis.


Assuntos
Biomarcadores Tumorais/genética , Aberrações Cromossômicas , Perfilação da Expressão Gênica , Melanoma/genética , Polimorfismo de Nucleotídeo Único/genética , Neoplasias Uveais/genética , Hibridização Genômica Comparativa , Estudos de Viabilidade , Formaldeído , Humanos , Hibridização in Situ Fluorescente , Melanoma/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Inclusão em Parafina , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias Uveais/patologia
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