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PubMed1998

Detection of chromosome over- and underrepresentations in hyperdiploid acute lymphoblastic leukemia by comparative genomic hybridization.

Chromosomal analysis of acute lymphoblastic leukemia (ALL) is often difficult because of the suboptimal in vitro growth of the immature lymphoid cell and the poor morphology obtained. In this study, we describe the application of comparative genomic hybridization (CGH) to investigate the genomic abnormalities in 14 patients with ALL, all of whom had cytogenetically identified numerical aberrations or gross chromosomal structural alteration. With the use of CGH, regional or whole chromosome overrepresentation or both were found to be more frequent than underrepresentation (52 gains vs. 6 losses), the most common gains being chromosomes 21 and X. The results of the comparison between CGH and conventional R-banding analysis could be classified into three categories: (1) in three cases, including two with trisomy, CGH and banding analysis gave identical results; (2) in six cases with hyperdiploidy and two cases presenting chromosome structural abnormalities, the results were consistent but with minor discrepancies; (3) in three cases, including two with triploidy and tetraploidy and one with chimeric karyotype together with +22, the data from CGH and cytogenetical analysis were discrepant. CGH could not find the triploidy and tetraploidy. Our results suggest that CGH has certain value in the detection of gains or losses of chromosome materials in hyperdiploid ALL. Nevertheless, the combination of CGH and conventional karyotyping provides more precise information on the genomic imbalance in ALL.

Adolescent↗
PubMed1995

Genomic structure and chromosomal location of the mouse pre-T-cell receptor alpha gene.

The mouse pre-T-cell receptor alpha (pT alpha) chain is a 33,000 M(r) glycoprotein expressed on the surface of immature thymocytes as a disulfide-linked heterodimer with the T-cell receptor beta (TCR beta) chain, and in association with proteins of the CD3 complex. The cDNA for pT alpha, isolated previously, encodes a type I transmembrane protein that is a member of the immunoglobulin (Ig) superfamily. Here we report the complete nucleotide sequence, the exon/intron structure, and the chromosomal location of the pTa gene. The gene spans about 8.4 kilobases (kb) and consists of four exons. Exon 1 encodes the 5' untranslated region, the leader peptide, and the first three amino acids of the mature protein. This exon is followed by a relatively long intron of 4.9 kb that contains many short interspersed repeats (SINEs) of the B1 and B2 family. The second exon encodes the extracellular Ig-like domain and exon 3 with just 45 base pairs the connecting peptide (CP), including the cysteine required for heterodimer formation. A similar exon/intron structure encoding corresponding parts of the mature polypeptide is found both in the Tcra and Tcrd constant region genes. The last exon encodes the transmembrane portion, the cytoplasmic tail, and about 540 nucleotides of 3' untranslated sequence, including a B2 repetitive element. In situ hybridization maps the pTa gene to the D/E1 region of mouse chromosome 17.

Animals↗
PubMed1977

Cytogenetic findings in pernicious anaemia. Comparison between results obtained with chromosome studies and the micronucleus test.

To elucidate whether the micronucleus test may be a sensitive test for the demonstration of the occurrence of spontaneous structural chromosomal aberrations in human disease, bone-marrow smears and chromosome preparations were studied from ten patients with pernicious anaemia. An increased incidence of metaphases with structural chromosomal aberrations was seen in three of the patients, whereas an increased number of bone-marrow cells containing micro-nuclei was present in eight of the ten patients. The micronucleus test may thus be a rapid and sensitive test to demonstrate whether spontaneous structural aberrations of the chromosomes are present in a group of patients suffering from various diseases.

Adult↗
PubMed1994

Comparison of the SmaI-digested chromosomes of Staphylococcus epidermidis and the closely related species Staphylococcus capitis and Staphylococcus caprae.

Pulsed-field gel electrophoresis was used to examine the chromosomal polymorphisms existing within and between four closely related members of the Staphylococcus epidermidis species group, S. epidermidis, Staphylococcus caprae, Staphylococcus capitis subsp. capitis, and S. capitis subsp. ureolyticus. SmaI was chosen as the restriction endonuclease for this study because it generated only a few well-separated chromosomal fragments. Each of the species and subspecies showed distinct SmaI digest patterns. The strains examined in this study were collected over a 20-year period from various geographical locations. The results indicate that DNA fragment patterns are unique to each species and subspecies and represent a reasonably stable component in the chromosome structure. S. caprae and S. capitis demonstrated considerable conservation in chromosome structure as indicated by the large numbers of conserved SmaI digest fragments. The polymorphisms found within each species appear to be linked to the species' character variability. The genome size of each Staphylococcus strain was extrapolated from the SmaI digest fragment pattern obtained by pulsed-field gel electrophoresis. The average genome size for S. epidermidis is 2,364 +/- 119 kb; for S. caprae strains from humans it is 2,600 +/- 157 kb and for S. caprae strains from goats it is 2,493 +/- 15 kb; for S. capitis subsp. capitis it is 2,456 +/- 71 kb; and for S. capitis subsp. ureolyticus it is 2,276 +/- 90 kb.

Animals↗
PubMed1997

Elasticity and structure of eukaryote chromosomes studied by micromanipulation and micropipette aspiration.

The structure of mitotic chromosomes in cultured newt lung cells was investigated by a quantitative study of their deformability, using micropipettes. Metaphase chromosomes are highly extensible objects that return to their native shape after being stretched up to 10 times their normal length. Larger deformations of 10 to 100 times irreversibly and progressively transform the chromosomes into a "thin filament," parts of which display a helical organization. Chromosomes break for elongations of the order of 100 times, at which time the applied force is around 100 nanonewtons. We have also observed that as mitosis proceeds from nuclear envelope breakdown to metaphase, the native chromosomes progressively become more flexible. (The elastic Young modulus drops from 5,000 +/- 1,000 to 1,000 +/- 200 Pa.) These observations and measurements are in agreement with a helix-hierarchy model of chromosome structure. Knowing the Young modulus allows us to estimate that the force exerted by the spindle on a newt chromosome at anaphase is roughly one nanonewton.

Anaphase↗
PubMed1992

Benomyl-induced aneuploidy in mouse oocytes.

Benomyl (methyl-1-[butylcarbamoyl]-2-benzimidazole carbamate) is a plant fungicide which acts by inhibiting tubulin polymerization. It is also a carcinogen and a teratogen. A substantial number of reports consistently show that benomyl inhibits cellular division and induces numerical chromosome changes in somatic cells, while results from standard genotoxicity assays which measure mutations and structural chromosome aberrations are conflicting. To define further the genotoxic effects of benomyl and to demonstrate the utility of the in vivo mouse oocyte assay for detecting chemicals which induce numerical chromosome changes, we investigated the ability of benomyl to induce numerical and structural chromosome aberrations in mouse oocytes. Superovulated female ICR mice were administered benomyl by oral gavage and oocytes were collected 17 h later. The proportions (and percentages) of hyperploid oocytes were 1/309(0.3), 6/155(3.9), 38/229(16.6), 46/130(35.4), 60/215 (27.9), 42/143(29.4) for control, 500, 1000, 1500, 1750 and 2000 mg/kg respectively. No increase in structural aberrations was observed. These results demonstrate that benomyl specifically induces numerical chromosome changes in mouse oocytes.

Aneuploidy↗
PubMedDate not supplied

Structural DNA and genetically active DNA in dinoflagellate chromosomes.

High resolution electron microscope autoradiographs of [3H]adenine incorporation in the dinoflagellate Prorocentrum micans suggest that RNA transcription occurs on extrachromosomal DNA filaments, but not on DNA in the main body of the chromosome. This genetically inactive DNA has an important role, however, in stabilising chromosome structure by its association with protein matrix. Evidence for the importance of this molecular association (which is probably cation-mediated) is provided by alkaline buffer extraction of the protein matrix in chromosomes of Amphidinium carterae , leading to complete destabilisation of the DNA framework. The clear distinction between structural DNA and genetically active DNA in these chromosomes provides a marked contrast to normal eucaryote chromosomes. This distinction is related to the occurrence of high DNA values in these organisms, and the evolutionary status of the dinoflagellate chromosome.

Adenine↗
PubMed1998

Structure and chromosomal localization of a murine LIM/homeobox gene, Lhx8.

Lhx8 is a LIM-homeodomain protein, containing two tandemly repeated LIM motifs and a hemeodomain. The expression of Lhx8 is limited spatially to the medical ganglionic eminence and the mesenchyme surrounding the oral cavity and temporally from middle embryonic to early postnatal development, suggesting a role for Lhx8 in differentiation of certain neurons and mesenchymal cells, just as the other LIM-homeodomain proteins are implicated in determining the fates of certain cell types. Here we report the structure and the chromosomal localization of the Lhx8 gene. The gene is composed of nine exons and eight introns. The first LIM domain is coded by two exons, exons 2 and 3, and the second by a single exon, exon 4. The homeodomain is encoded by three exons, exons 6, 7, and 8. In situ chromosomal hybridization demonstrated that the Lhx8 gene was localized in the distal region of mouse chromosome 3.

Animals↗
PubMed1995

Structure and chromosomal localization of a human water channel (AQP3) gene.

A cDNA encoding rat AQP3, a water channel and a member of the MIP family, that is expressed predominantly in kidney medulla and colon was cloned recently. To determine the structure, tissue distribution, and chromosomal localization of the human AQP3 gene, we screened a human kidney cDNA library with rat AQP3 probe and isolated a cDNA coding for human AQP3 protein. The deduced amino acid sequence of human AQP3 was 91% identical to rat AQP3. Human AQP3 mRNA was expressed in colon, kidney, liver, pancreas, lung, peripheral leukocytes, spleen, and prostate. The human AQP3 gene was mapped to 7q36.2-q36.3 by chromosome fluorescence in situ hybridization.

Amino Acid Sequence↗
PubMed1986

[Characteristics of the morphology and mitotic condensation of human Y chromosomes with structural rearrangements].

Parameters of the length and mitotic condensation were investigated in the following cases of Y-chromosome aberrations: isodicentric Y(q), Y-chromosome without heterochromatic block, and Y-chromosome with satellites. In the Ydic we revealed some differences between f-block, that is located near the inactive kinetochore, and the block near the active centromere. Satellites exert no influence on the mitotic function of Y chromosome, presumably owing to the presence of C-heterochromatic material. With the absence of heterochromatic region, a decline in condensation of the non-fluorescent segment was observed in addition to a simultaneous increase in its length. The mechanism of functioning of the structural heterochromatin is discussed.

Adult↗
PubMed1980

[DNA molecule interaction in the contact mechanism of chromosome aberration formation].

The scheme of the formation of structural chromosome mutations, based on hydrogen binding of double-stranded DNA in the sites of palindrome sequencies is proposed. According to this scheme the mutagen damage in palindromes, forming chromosome loops, leads to the formation of structural mutations. In lack of contact between double-stranded regions of chromosomes the restoration of its structure occurs. The molecular mechanism of the formation of structural chromosome mutation is considered from the point of view of repair hypothesis and explains the gene position effect.

Animals↗
PubMed1981

Clinicopathological conference: a newborn monozygotic twin with abnormal facial appearance and respiratory insufficiency.

The second of twins males expired of respiratory insufficiency shortly after birth. Unusual facial appearance included prominent forehead, flat nasal bridge, widely separated inner canthi, downward slanting eyes with narrow palpebral fissures, epicanthic folds, small mouth and micrognathia, and apparently low-set ears; there was also cryptorchidism bilaterally and a simian crease bilaterally. The pregnancy of the 19-year-old black woman was not unusual, but polyhydramnios accompanied the delivery of this twin. The twin placentae were diamniotic and monochorionic, one being slightly immature with a two-vessel cord. We interpreted the karyotype as 46,XY,del(10) (p11-15): The brother and parents were normal. The dysmorphic features of this and three previously reported cases of 10p- do not permit definition of a syndrome. These are apparently the first monozygous twins presenting discordance of chromosomal structure; previously reported chromosomal discordance in monozygous twins involved numerical abnormality. Considering that the mechanism monozygous twinning is not understood, we note that the occurrence of both twinning and a structural aberration in one of the twins suggests the possibility of a common cause.

Abnormalities, Multiple↗
PubMed2001

Genomic structure and chromosome location of the human gene encoding the zinc finger autoantigen ZNF330.

We have recently described a novel zinc finger cDNA, ZNF330, which was immunologically characterized as a new human autoantigen, highly conserved during evolution from nematodes to humans. The protein was found at the nucleolus and the cytoplasm in interphase and transiently associates with centromeres in mitosis as determined by immunofluorescence analysis. We now describe that the association of ZNF330 with the nucleolus but not with the cytoplasm is RNA-dependent as shown by RNAse treatment of fixed culture cells, since ZNF330 localization was unaffected by DNAse treatment. We also report the cloning, structural organization and chromosome location of the human ZNF330 gene. The gene is comprised of 10 exons and spans approximately 16 kb of genomic DNA. The conserved residues forming nine CXXC motifs are contained in exons 3 to 9. Several major transcription initiation sites were located 126, 124 and 121 bp upstream of the translation initiation codon ATG, as determined by primer extension analysis. The human ZNF330 gene was mapped by FISH to chromosome 4q31.1-->q31.2, the site of the FRA4C locus previously described as a common fragile site for acquired chromosome instability in humans.

Animals↗
PubMed1995

Genomic structure and chromosomal localization of the mouse LIM/homeobox gene Lhx3.

We have previously cloned the murine Lhx3 cDNA that encodes a predicted protein containing two tandemly repeated LIM domains and a homeodomain. Early expression of Lhx3 in oral ectoderm that is committed to contribute to the anterior and intermediate lobes of the pituitary and its perseverance in the adult gland strongly suggest an involvement of the gene in mediating and maintaining the differentiation program of this important endocrine system. Additional functions are suggested by the fact that Lhx3 is also expressed bilaterally along the spinal cord and the hindbrain at early stages of mouse development. Here we report the structural organization and chromosomal localization of the Lhx3 gene. The gene is composed of six exons and five introns. Two different exons, Ia and Ib, appear to be alternatively spliced to exon II. The first LIM domain is encoded by exon II and the second by exon III. The homeobox is shared by exons IV and V. We have mapped Lhx3 to the proximal region of mouse chromosome 2 in a region that shares homology with human chromosomes 9q and 10p.

Amino Acid Sequence↗
PubMed1992

Advances in the detection of ploidy differences in cancer by in situ hybridization.

Three main techniques allow the detection of changes in the cellular genomic content. The karyotyping procedure on metaphase spreads can give specific information on chromosome number and structural chromosome changes, but analyses are restricted to a limited number of chromosome spreads. Furthermore, cell culturing of (in particular solid) cancer specimens can result in selection of a minor tumour cell population with a high proliferative capacity. On the other hand, flow cytometry allows the analyses of large numbers of cells, but does not detect small variations in the DNA content or structural changes. The fluorescent in situ hybridization (FISH) procedure combines the advantages of the two former procedures, in that relatively large numbers of cells can be analysed easily and specific chromosomal changes can be detected.

DNA Probes↗
PubMed1995

Analysis of chromosomal abnormalities in human sperm after chemotherapy by karyotyping and fluorescence in situ hybridization (FISH).

The frequency of numerical and structural chromosomal abnormalities was studied in the sperm of a lymphoma patient 3 years after MACOP-B chemotherapy (CT). Sperm karyotyping was performed by fusion of human sperm with hamster oocytes and analysis of 193 Q-banded sperm chromosomes. Multicolor fluorescence in situ hybridization (FISH) was performed on 10,228 sperm for analysis of disomy frequencies for chromosomes 1 and 12 and on 10,664 sperm for chromosomes X and Y. Sperm karyotyping demonstrated numerical abnormalities in 7.3% of the spreads, 6.7% hypohaploid and 0.5% hyperhaploid, giving a conservative estimate of aneuploidy of 1%. Structural chromosomal abnormalities were present in 7.3% of the karyotypes and 0.5% had both numerical and structural abnormalities. Results of FISH analyses yielded disomy frequencies of 0.10%, 0.11%, 0.04%, 0.05%, and 0.18% for chromosomes 1, 12, X, Y, and XY, respectively. The frequency of diploid sperm was 0.09%. The frequency of abnormalities was not significantly increased compared to control donors for any of the studies. Also, the frequencies of X- and Y-bearing sperm did not differ significantly from 50% in the sperm karyotyping or FISH studies.

Aneuploidy↗
PubMed1994

Genomic structure and chromosomal location of the rat gene encoding the zinc finger transcription factor Kid-1.

We have previously cloned and sequenced a novel zinc finger cDNA, Kid-1, from the rat. Because of its developmentally regulated expression pattern and its suppression after renal injury, as well as its kidney-predominant expression, we propose that Kid-1 is likely to play an important role in renal gene regulation. Kid-1 encodes a predicted protein with 13 zinc fingers at the carboxy end and Krüppel-associated box (KRAB) A and B regions at the amino terminus. Expression of a Kid-1-GAL4 chimeric protein results in strong transcriptional repression of cotransfected constructs containing GAL4 binding sites and a chloramphenicol acetyl transferase gene driven by either a minimal promoter or a SV40 enhancer. We now report the cloning, structural organization, and chromosomal localization of the Kid-1 gene. The Kid-1 gene is composed of four exons and three introns, closely reflecting the organization of the Kid-1 protein. The KRAB A and B regions are encoded by the second and third exons, respectively. The entire zinc finger region is encoded by the fourth exon. Using a combination of linkage analysis and somatic cell hybrid analysis, Kid-1 was mapped to rat chromosome (RNO) 10. Kid-1, Il3, and Sparc form a tight linkage group on RNO10. Regional sublocalization to RNO10q21.3-q22 was established by fluorescence in situ hybridization.

Amino Acid Sequence↗
PubMed2006

Structure of interphase chromosomes in the nuclei of Drosophila cells.

Fluorescent images of interphase chromatin structures and chromosome structures isolated from reversibly permeable Drosophila cells were analyzed. Decondensed chromatin in early S phase (2.0-2.5 C-value) consisted of a veil-like fibrillary network. Fibrillar chromatin formed rodlets later in the early S phase (2.5-2.75 C). Drosophila chromosomes contain several smaller subunits called rodlets. Fibrillar chromatin turned to chromatin ribbon and the early mid-S-phase globular chromosomes (2.75-3.0 C), then to opened fibrous globular forms later in the mid-S-phase (3.0-3.25 C), to late-S-phase supercoiled ribbons (3.25-3.5 C), end-S-phase elongated prechromosomes (3.5-3.75 C), bent and linear chromosomes (3.75-4.0 C). Early-S phase chromatin fibrils in the nuclei of Drosophila cells are thinner than the veil-like structures in mammalian cells. The connectivity of chromosomes shows linear arrangement (3, 1, 2, 4), with larger chromosomes (1 and 2) inside and smaller chromosomes (3, 4) at the two ends in the chromosomal chain.

Animals↗