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At least 577 records · Page 32Linked to original sources
PubMed1988

Structural chromosomal abnormalities in human medulloblastoma.

Seven human medulloblastomas (four primary cerebellar, three recurrent or metastatic) were karyotyped in direct preparation and/or short-term or early culture. One tumor had a 46,XX stem line. Four of the six remaining tumors contained one or more i(17q), and three of these six tumors had deletions of extra copies of chromosome #1, resulting in trisomy of 1p, 1q, or both. Two tumors had near-centromeric breaks of chromosome #3, two tumors contained unbalanced translocations with breakpoints at 20q13, and two tumors contained double minutes. These findings suggest that the primary karyotypic deviations of human medulloblastomas are gains of whole chromosomes, which are then either deleted or involved in unbalanced translocations, resulting in partial trisomies.

Adolescent↗
PubMed1988

Multiple structural chromosome rearrangements, including del(7q) and del(10q), in an adenocarcinoma of the prostate.

Cytogenetic analysis of a poorly differentiated adenocarcinoma of the prostate revealed the complex karyotype: 76-86,X, -Y, +X, +X, +del(X)(q24), +t(1;10) (p22;q24), -2, +der(2) t(1;2;?)(p32;q24p13;?), +der(2)t(1;2;?) (p32;dq24p13;?), +3, +3, +4, +5, +5, +6, +7, +del(7) (q22), -8, +der(8)t(8;?)(q24;?), + der(8)t(8;?)(q24;?), +9, +10, +10, +der(10)t (1;10)(q24;q22), +del (10)(q23), +11, +11, +12, +der(12)t(4;12)(q11;p11), +der(12)t(4;12) (q11;p11), +14, +der (15)t(1;15)(q21;p11), +t(16;?) (q21;?), +17, +18, +19, +19, +20, +20, +21, +22, +2-5 mar. The karyotype contains deletions of both 7q and 10q, abnormalities that also have been described previously in prostatic adenocarcinomas, and which hence may represent primary chromosomal rearrangements in this type of cancer.

Adenocarcinoma↗
PubMed1989

Structural chromosome aberrations in an adamantinoma.

Cytogenetic analysis of a tibial adamantinoma, a malignant tumor that has hitherto not been characterized chromosomally, revealed as the only abnormalities the two apparently balanced translocations, t(1;13;22)(q22;q12;p13) and t(15;17)(q12;p13).

Adolescent↗
PubMed1992

Significance of both numerical and structural chromosomal abnormalities in clear cell sarcoma.

We analyzed cytogenetically two cases of clear cell sarcoma. The t(12;22)(q13;q13) hypothesized to be characteristic of clear cell sarcoma was detected in one of the two cases. Although this translocation was not observed in the other case; trisomy of chromosome 22 was, as were other numerical abnormalities. This latter observation has also been described in other reported studies of clear cell sarcoma. These findings confirm the nonrandomness of t(12;22)(q13;q13) in clear cell sarcoma, but also suggest that in its absence other abnormalities of chromosome 22 are significant. Trisomy 8, noted in both cases we report, as well as in previous studies, also appears to play an important role in clear cell sarcoma.

Adult↗
PubMed1991

Structure, chromosomal localization and evolutionary conservation of the gene encoding human U1 snRNP-specific A protein.

Three specific proteins, called A, 70K and C, are present in the U1 small nuclear ribonucleoprotein (snRNP) particle, in addition to the common proteins. The human U1 snRNP-specific A protein is, apart from a proline-rich region, highly similar to the U2 snRNP-specific protein B". To examine the homologous regions at the genomic level, we isolated and characterized the human U1-A gene. The human U1-A protein appears to be encoded by a single-copy gene and its locus has been mapped to the q arm of chromosome 19. The gene, about 14-16 kb in length, consists of six exons. The regions homologous to the U2-B" gene are not limited to single exons and are mostly not confined by exon-exon junctions in the corresponding U1-A mRNA. However, the proline-rich region of U1-A, absent in U2-B", is encoded by a single exon, suggesting a specific function for this domain of U1-A. The region of the cap site and upstream sequences contain interesting similarities to the promoter region of other snRNP protein-encoding genes and several housekeeping genes, in particular the vertebrate ribosomal protein-encoding genes. Hybridization experiments with various vertebrate genomic DNAs revealed that U1-A sequences are evolutionarily conserved in all tested vertebrate genomes, except for chicken, duck and pigeon. The divergence of these avian genomes is probably typical for the class of birds.

Amino Acid Sequence↗
PubMed1998

Structure, chromosome localization, and tissue distribution of the mouse twik K+ channel gene.

We have recently discovered a new class of potassium channels with two pore-forming domains and four membrane-spanning domains. When heterologously expressed, these channels produce time- and voltage-independent currents that classify them as background or leak channels. TWIK (for tandem of P domains in a weak inwardly rectifying K+ channel) was the first member of this family to be cloned. Here, we describe the genomic organization of TWIK in the mouse. The coding sequence as well as the untranslated sequences are contained in three exons. The twik gene (or KCNK1) has been mapped to chromosome 8, consistent with its localization to 1q42-43 in human. The twik gene is expressed in virtually all mouse tissues. It is most abundantly expressed in brain and moderately in other organs such as kidney. The level of expression is increased in brain and kidney from neonate to adult animals, but the TWIK message is also detected during embryogenesis, as early as day 7 post conception.

Animals↗
PubMed2002

Importance of detecting numerical versus structural chromosome aberrations.

The aim is to review briefly the key questions related to aneuploidy/polyploidy and to compare the advantages and disadvantages of the in vitro micronucleus test to assess aneuploidy/polyploidy in vitro. The key questions that will be addressed, concern the importance of polyploidy for health, and cancer in particular, the mechanisms leading to aneuploidy and polyploidy, and the survival of aneuploid/polyploid cells. The recently recognised contribution of numerical chromosome changes to carcinogenesis triggered the development and the implementation of tests specifically aiming at the detection of aneugens in the test battery for mutagenicity and carcinogenicity. The validation of the in vitro micronucleus test in combination with the identification of in vitro divided cells with the cytokinesis-block methodology and of centromeres with pancentromeric or chromosome specific centromeric probes fluorescence in situ hybridisation (FISH) provides a sensitive, easy to score and powerful test which allows assessment of cell proliferation, the discrimination between chromosome breaks, chromosome loss and chromosome non-disjunction and polyploidy. Moreover, classic histology permits the estimation of necrosis and apoptosis on the same slide. The cytokinesis-blocked micronucleus assay could be considered as a multi-endpoint test for genotoxic responses to clastogens/aneugens. This methodology has also shown to be capable of identifying threshold values for the induction of chromosome loss and/or non-disjunction by microtubule inhibitors, data which are particularly important for risk calculations. Similar approaches were conducted in vivo on bone marrow in mice and rats (except for identification of chromosome non-disjunction), and are in development for gut in mice.

Aneuploidy↗
PubMed2000

Primary structure, chromosomal mapping, expression and transcriptional activity of murine hepatocyte nuclear factor 4gamma.

We demonstrate the presence of a new member of the orphan nuclear receptor hepatocyte nuclear factor 4 (HNF4) subfamily in mouse which is genetically distinct from the previously characterized mouse HNF4alpha gene. The new member of the HNF4 subfamily shows highest amino acid identity, similar tissue distribution and syntenous chromosomal localization to the recently described human HNF4gamma (NR2A2), we therefore classify it as mouse HNF4gamma (mHNF4gamma). A combination of RT-PCR and immunohistochemical analysis showed expression of mHNF4gamma mRNA and protein in the endocrine pancreas, testes, kidney and gut. By co-transfection experiments, we show that mHNF4gamma is able to activate transcription, acting through binding sites that have been previously characterized as HNF4alpha binding sites. The presence of HNFgamma in human and mouse implies that a complex transcriptional network exists in higher vertebrates involving a number of HNF4 members with overlapping yet distinct function and tissue distribution.

Animals↗
PubMed1998

Cloning, structure, chromosomal localization and promoter analysis of human 2-oxoglutarate dehydrogenase gene.

Human 2-oxoglutarate dehydrogenase (OGDH) is an E1-component of the OGDH multi-enzyme complex and catalyzes both the ThDP-dependent decarboxylation of 2-oxoglutarate and the subsequent reductive succinylation of the lipoyl moiety which is covalently bound to the E2 component, dihydrolipoamide succinyltransferase. The cDNA and genomic DNA encoding human OGDH has been cloned and sequenced. The cDNA contains a 3006-bp open reading frame encoding a 40-amino acid leader peptide and a 962-amino acid mature OGDH protein (Mr=108878). The gene contains 22 exons spanning approximately 85 kb. The putative ThDP-binding sequence motif is identified in both DNAs. The gene is localized to chromosome 7 at p13-p14 by fluorescence in situ hybridization. With the TATA- and CAAT-less 5'-flanking region (wild type, -3276/+212) of the OGDH gene-luciferase reporter vector construct and its nested deletion or linker-scanning mutant constructs the transient reporter expression assays in BHK-21 cells reveal the existence of two 10-bp cis-acting elements (-53/-44 and -33/-24) and two trans-acting elements (-536/-496 and -93/-84). A nuclear factor that binds to the region from -63 to -24 including two cis-acting elements.

Amino Acid Sequence↗
PubMed1998

Structural chromosome rearrangements in couples with recurrent fetal wastage.

OBJECTIVE: A review of the cytogenetic data in 1743 couples (3486 patients) with recurrent fetal wastage (RFW) who were examined for RFW at the Leuven Centre for Human Genetics in the period 1986-1995. These results were compared with a previous study in the period 1970-1985. SUBJECTS: Patients who had at least two first trimester miscarriages or patients who had a spontaneous first trimester abortion, preceded or followed by a second or third trimester fetal death. RESULTS: Chromosomal rearrangements were found in 5.34%. Two-thirds of these chromosomal rearrangements were autosomal balanced translocations. This finding is a 30-fold increase compared to the general population. Other chromosomal abnormalities included Robertsonian translocations, inversions and sex-chromosomal abnormalities. DISCUSSION: The Leuven experience was compared with several other studies. Mechanisms causing these chromosomal abnormalities are presented. CONCLUSIONS: Chromosomal analyses are an important and necessary part of the etiological investigations in couples with RFW.

Abortion, Habitual↗