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PubMed2004

Microdissection and molecular manipulation of single chromosomes in woody fruit trees with small chromosomes using pomelo (Citrus grandis) as a model. I. Construction of single chromosomal DNA libraries.

Construction of single chromosomal DNA libraries by means of chromosome microdissection and microcloning will be useful for genomic research, especially for those species that have not been extensively studied genetically. Application of the technology of microdissection and microcloning to woody fruit plants has not been reported hitherto, largely due to the generally small sizes of metaphase chromosomes and the difficulty of chromosome preparation. The present study was performed to establish a method for single chromosome microdissection and microcloning in woody fruit species using pomelo as a model. The standard karyotype of a pomelo cultivar ( Citrus grandis cv. Guanxi) was established based on 20 prometaphase photomicrographs. According to the standard karyotype, chromosome 1 was identified and isolated with fine glass microneedles controlled by a micromanipulator. DNA fragments ranging from 0.3 kb to 2 kb were acquired from the isolated single chromosome 1 via two rounds of PCR mediated by Sau3A linker adaptors and then cloned into T-easy vectors to generate a DNA library of chromosome 1. Approximately 30,000 recombinant clones were obtained. Evaluation based on 108 randomly selected clones showed that the sizes of the cloned inserts varied from 0.5 kb to 1.5 kb with an average of 860 bp. Our research suggests that microdissection and microcloning of single small chromosomes in woody plants is feasible.

Blotting, Southern↗
PubMed2004

Microdissection and molecular manipulation of single chromosomes in woody fruit trees with small chromosomes using pomelo (Citrus grandis) as a model. II. Cloning of resistance gene analogs from single chromosomes.

Amplification of resistance gene analogs (RGAs) is both a useful method for acquiring DNA markers closely linked to disease resistance (R) genes and a potential approach for the rapid cloning of R genes in plants. However, the screening of target sequences from among the numerous amplified RGAs can be very laborious. The amplification of RGAs from specific chromosomes could greatly reduce the number of RGAs to be screened and, consequently, speed up the identification of target RGAs. We have developed two methods for amplifying RGAs from single chromosomes. Method 1 uses products of Sau3A linker adaptor-mediated PCR (LAM-PCR) from a single chromosome as the templates for RGA amplification, while Method 2 directly uses a single chromosomal DNA molecule as the template. Using a pair of degenerate primers designed on the basis of the conserved nucleotide-binding-site motifs in many R genes, RGAs were successfully amplified from single chromosomes of pomelo using both these methods. Sequencing and cluster analysis of RGA clones obtained from single chromosomes revealed the number, type and organization of R-gene clusters on the chromosomes. We suggest that Method 1 is suitable for analyzing chromosomes that are unidentifiable under a microscope, while Method 2 is more appropriate when chromosomes can be clearly identified.

Amino Acid Sequence↗
PubMed2000

Chromosome activities in cleaving mouse embryos to construct prenucleolar bodies orienting an intranuclear chromosome-chromosome configuration.

Most chromosomes of cleaving mouse embryos formed spherical structures called as prenucleolar bodies. Embryos stained with fluorescing dyes selective for AT-rich regions of DNA indicated that chromosome centromeres were organized by prenucleolar bodies and that chromosomes at pre-prophase of the cleavage division started to condense with their centromere regions aligned towards the peripheries of spheres. Embryo chromosomes as well as prenucleolar bodies were shown to bind a monoclonal antibody to spliceosomal snRNAs, which are contrasted to the nucleoli or chromosomes of somatic cells. More than 10 prenucleolar bodies were found in the pronuclei at the earliest stage after fertilization and 40 of them at most, diploid number of chromosomes of the mouse, in the nuclei of the 2-cell embryos. The number was decreased later in the cell cycles and at the 4-cell stage. Hence, every chromosome of cleaving mouse embryos is highly active in constructing prenucleolar bodies and behaves during the interphase until mitosis as a unit of the body; either as a single unit or as a member of the units fused. In other words, the prenucleolar bodies function as centers orienting chromosome-chromosome configuration in the fertilized eggs.

Adenine↗
PubMed2002

Sheep/human comparative map in a chromosome region involved in scrapie incubation time shows multiple breakpoints between human chromosomes 14 and 15 and sheep chromosomes 7 and 18.

A chromosome region involved in scrapie incubation time was identified on sheep chromosome 18 (OAR18). Since OAR18 (and OAR7) share conserved chromosome segments with human chromosomes HSA14 and HSA15, a dense map of type I markers was constructed by FISH mapping of bacterial artificial chromosomes containing genes located on these human chromosomes. In this study, we used the complete human sequence information (gene positions in megabases, Mb) to locate approximately one gene every 2 Mb on HSA15 (19 genes mapped between 19.51 and 66.02 Mb) and on HSA14 (11 genes between 73.24 and 102.62 Mb). Combined with previous work carried out in cattle and goats, our results made it possible to refine the comparative map between ruminants and humans for these two highly rearranged chromosomes (10 segments on HSA15 and 7 on HSA14). Furthermore, we identified relatively short intervals containing evolutionary breakpoints, which is a prerequisite to position them precisely. This work is also the first step in the cloning of the region involved in scrapie incubation period in sheep.

Animals↗
PubMed2000

Screening for specific chromosome involvement in hematological malignancies using a set of seven chromosome painting probes. An alternative approach for chromosome analysis using standard FISH instrumentation.

We report the application of multi-color fluorescence in situ hydribidization (FISH) for bone marrow metaphase cell analysis of hematological malignancies using a sub-set of the human karyotype for chromosome painting. A combination of chromosome probes labeled with three haptens enabled the construction of a "painting probe" which detects seven different chromosomes. The probe was used to screen three chronic myeloid leukemia (CML) derived cell lines and ten CML patient bone marrow samples for aberrations, additional to the Ph rearrangement, that are associated with the onset of blast crisis of CML. This approach was shown to identify karyotype changes commonly seen by conventional karyotyping, and in addition revealed chromosome changes unresolved or undetected by conventional cytogenetic analysis. The seven-color painting probe provides a useful, fast, and reliable complementary tool for chromosome analysis, especially in cases with poor chromosome morphology. This is a simple approach, since the probes can be displayed in a standard red/green/blue format accessible to standard fluorescence microscopes and image-processing software. The proposed approach using panels of locus-specific probes as well as chromosome paints will be useful in all diagnostic routine environments where analysis is directed towards screening for genetic rearrangements and/or specific patterns of chromosome involvement with diagnostic/prognostic value.

Chromosome Aberrations↗
PubMed1987

Hypothesis: some mutagens directly alter specific chromosomal proteins (DNA topoisomerase II and peripheral proteins) to produce chromosome stickiness, which causes chromosome aberrations.

Recent biochemical and molecular biological data on the composition and structure of the chromosome and the nucleus, combined with observations on the chromosomes of mutant yeast cells and grasshopper neuroblasts, offer new perspectives on mutagen-induced chromosome stickiness and its relation to chromosome breakage. A hypothesis consistent with these data states that chromosome stickiness (i) results from changes in specific non-histone proteins (topoisomerase II and the peripheral proteins) that are integral components of the chromosome and whose function is necessary for separation and segregation of chromatids, the changes being caused either by mutation in structural genes for the proteins (heritable stickiness) or by direct action of mutagens on the proteins (induced stickiness); (ii) occurs in various degrees (slight, moderate, severe, extreme) that are determined by the number of target protein molecules affected, a certain number (threshold) of affected molecules at a given site on a chromosome being required to resist the forces of anaphase movement in order to produce microscopically detectable stickiness; (iii) results from molecular events that can occur at several phases of the cell cycle (including interphase), but can only be recognized at prometaphase, metaphase and anaphase; and (iv) causes chromosome aberrations by the physical stretching and breaking of chromatids at the sticky sites; hence the breakage resulting from stickiness is a secondary effect that requires anaphase movement, in contrast to breakage resulting from direct action of mutagens on DNA.

Animals↗
PubMed1995

Use of multicolour chromosome painting to identify chromosomal rearrangements in human lymphocytes exposed to bleomycin: a comparison with conventional cytogenetic analysis of Giemsa-stained chromosomes.

Exchange aberrations induced by bleomycin were identified by multicolour fluorescence in situ hybridisation (FISH) with probes for chromosomes 1, 2, and 3. The frequency and distribution of aberration types were compared to conventional metaphase analysis of Giemsa-stained chromosomes from the same human lymphocyte cultures. The total percentage of exchanges detectable by painting three pairs of chromosomes with separate colours was calculated as 40%. Giemsa staining revealed predominantly asymmetric chromosome exchanges, which are expected to comprise 50% of the total induced exchanges. Genomic exchange frequencies were, therefore, determined by multiplying the observed frequencies from FISH analysis by 2.5 and the number of asymmetric exchanges identified in Giemsa-stained slides by 2.0. By these calculations, the genomic exchange frequency calculated from chromosome painting exceeded that estimated by Giemsa-staining. This difference was due to the identification by chromosome painting of a unique class of cells in which chromosomes had undergone complex exchanges (nonreciprocal exchanges involving multiple mutual sites). The percentage of cells exhibiting exchanges was similar for both methods.

Azure Stains↗
PubMed1996

Chromosome aberration analysis in atomic bomb survivors and Thorotrast patients using two- and three-colour chromosome painting of chromosomal subsets.

Chromosomal translocations in peripheral lymphocytes of three healthy Hiroshima atomic (A)-bomb survivors, as well as three Thorotrast patients and two non-irradiated age-matched control persons from the German Thorotrast study were studied by two- and three-colour fluorescence in situ hybridization (chromosome painting) with various combinations of whole chromosome composite probes, including chromosomes 1, 2, 3, 4, 6, 7, 8, 9 and 12. Translocation frequencies detected by chromosome painting in cells of the A-bomb survivors were compared with results obtained by G-banding. A direct comparison was made, i.e. only those cells with simple translocations or complex aberrations detected by G-banding were taken into consideration which in principle could be detected also with the respective painting combination. The statistical analysis revealed no significant differences from a 1:1 relationship between the frequencies of aberrant cells obtained by both methods. The use of genomic translocation frequencies estimated from subsets of chromosomes for biological dosimetry is discussed in the light of evidence that chromosomes occupy distinct territories and are variably arranged in human lymphocyte nuclei. This territorial organization of interphase chromosomes implies that translocations will be restricted to chromatin located at the periphery of adjacent chromosome territories.

Aged↗
PubMed2002

Ring chromosome 21 in a boy and a derivative chromosome 21 in the mother: implication for ring chromosome formation.

We report on r(21) chromosome in a boy and a der(21) chromosome in his mother. Cytogenetic studies revealed a mosaic 45,XY[4]/46,XY,r(21)[96] karyotype in the boy and a 46,XX,der(21)[100] karyotype in the mother. Fluorescence in situ hybridization analysis for D21Z1 at the centromere, AML1 at 21q22.1, LSI21 at 21q22.2, and 21qtel at the telomere region showed that the r(21) chromosome retained single copies of D21Z1, AML1, and LSI21 and lacked the 21qtel, whereas the der(21) chromosome had two copies of the 21qtel on both of its ends and single copies of D21Z1, AML1, and LSI21, with a paracentric inversion of AML1 and LSI21 (21qtel-D21Z1-LSI21-AML1-21qtel). Microsatellite analysis for nine loci on 21q22.3 indicated that the r(21) chromosome was missing a distal 21q22.3 region involving D21S1890, D21S1411, and D21S1903 with no maternally derived alleles, and that the der(21) chromosome was associated with duplication of a distal 21q22.3 region encompassing D21S1890 and D21S1446. The results suggest that a U-type exchange occurred between the homologous distal 21q regions duplicated on the der(21) chromosome, leading to the r(21) formation. This is a novel mechanism put forward for the formation of a monocentric ring chromosome.

Child↗
PubMed1993

Resolution of four large chromosomes in penicillin-producing filamentous fungi: the penicillin gene cluster is located on chromosome II (9.6 Mb) in Penicillium notatum and chromosome I (10.4 Mb) in Penicillium chrysogenum.

Four chromosomes were resolved by pulsed field gel electrophoresis in Penicillium notatum (10.8, 9.6, 6.3 and 5.4 Mb in size) and in five different strains of Penicillium chrysogenum (10.4, 9.6, 7.3 and 6.8 Mb in the wild type). Small differences in size were found between the four chromosomes of the five P. chrysogenum strains. The penicillin gene cluster was localized by hybridization with a pcbAB probe to chromosome II of P. notatum and to chromosome I of all P. chrysogenum strains except the deletion mutant P. chrysogenum npe10, which lacks this DNA region. The pyrG gene was localized to chromosome I in P. notatum and to chromosome II in all P. chrysogenum strains except in the mutant AS-P-78 where the probe hybridized to chromosome III. A major chromosomal rearrangement seems to have occurred in this high penicillin producing strain. A fast moving DNA band observed in all gels corresponds to mitochondrial DNA. The total genome size has been calculated as 32.1 Mb in P. notatum and 34.1 Mb for the P. chrysogenum strains.

Chromosome Mapping↗
PubMed1995

Sequence of mouse Odf1 cDNA and its chromosomal localization: extension of the linkage group between human chromosome 8 and mouse chromosome 15.

The mouse cDNA encoding the major protein of the outer dense fibers in sperm tails was isolated by reverse transcription of testicular RNA and amplification with sequence-specific primers. Sequencing of a genomic clone obtained by inverse PCR yielded the 5' untranslated region. The transcription starting point was verified by primer extension. The putative proteins encoded by Odf1 in mouse and by ODF1 in rat and man are very similar. A total of 15 amino acids in the C-terminal region were deleted in the mouse protein, compared with the rat protein. Through in situ hybridization to metaphase chromosomes, the Odf1 gene was localized to mouse chromosome 15 region B2-C. The chromosomal localization of the Odf1 gene extends the hitherto known linkage group consisting of MYC (Myc), PVT1 (Pvt1), GPT (Gpt), and TG (Tg) common to human chromosome 8 and mouse chromosome 15 in the proximal direction of both chromosomes. The linkage group now extends from band q24 to band q22 of human chromosome 8 and from region D2-E to region B2-C of mouse chromosome 15.

Amino Acid Sequence↗
PubMed1972

Assignment of three human genes to chromosomes (LDH-A to 11, TK to 17, and IDH to 20) and evidence for translocation between human and mouse chromosomes in somatic cell hybrids (thymidine kinase-lactate dehydrogenase A-isocitrate dehydrogenase-C-11, E-17, and F-20 chromosomes).

Independently derived man-mouse somatic cell hybrids and their derivative subclones show a positive correlation between the expression of human lactate dehydrogenase A subunits and the occurrence of the human C-11 chromosome. Data are also presented that confirm the previously reported linkage of the thymidine kinase locus to the E-17 chromosome. A translocation of the E-17 chromosome provides presumptive evidence for the assignment of the thymidine kinase locus to the long arm segment of the E-17 chromosome. This translocation also provides evidence for translocation between man and mouse chromosomes in somatic cell hybrids. A presumptive association between the human phenotype for isocitrate dehydrogenase and the human F group is also described. Identification of specific human chromosomes was achieved by the application of several new cytological techniques: measurement of chromosome arm length, in situ annealing with mouse satellite complementary RNA, constitutive heterochromatin staining with Giemsa, and quinacrine mustard fluorochromatic staining.

Animals↗
PubMed1991

Rare chromosomal aberrations induced by vincristine. Partial endoreduplication and pseudoendoreduplication, segmentally endoreduplicated chromosomes, and segmental premature chromosome condensation.

Vincristine (VCR) is capable of inducing a cell containing both conventional chromosomes (monochromosomes) and diplochromosomes. A total of 124 such metaphases were examined by 5-bromodeoxyuridine (BrdU) incorporation and fluorescence plus Giemsa (FPG) technique to analyze cell cycle kinetics. The majority of cells (119 metaphases) showed differential BrdU incorporation between the two kinds of chromosomes, indicating that partial endoreduplication occurred in these cells. In addition, existence of partially endoreduplicated cells with premature chromosome condensation (PCC) in either mono- or diplochromosomes suggests that the timing of monochromosome-replication was very variable in individual cells. On the other hand, the remaining five metaphases showed that both mono- and diplochromosomes incorporated BrdU similarly, indicating that diplochromosomes are formed by pseudoendoreduplication. Two kinds of chromosomal aberrations probably caused by delay of DNA synthesis on chromosome segments, segmental endoreduplication, and segmental PCC were also reported. Segmental endoreduplication was defined as endoreduplication that occurred on some segments of chromosomes. Out of 119 partially endoreduplicated cells, 3 contained a chromosome consisting of both mono- and diplochromosomal segments, indicating that the former segments missed one round of DNA synthesis. Segmental PCC was defined as PCC restricted to only some segments of chromosomes. Two types of segmental PCC, segmental S-PCC and G2-PCC, were observed in VCR-induced ordinary polyploidy. Although both segmental endoreduplication and segmental PCC occurred with very low frequency, these phenomena suggest that DNA synthesis was disturbed in some part of the nucleus.

Aneuploidy↗
PubMed1978

Quantitative studies on the arrangement of human metaphase chromosomes. V. The association pattern of acrocentric chromosomes in human meningiomas after the loss of G and D chromosomes.

The association pattern was studied in 2715 mitoses of 90 meningiomas with different numbers of acrocentric chromosomes. In cells with monosomy 22, a significant increase of mitoses with associations was observed in comparison to cells with a normal karyotype. The number of associating acrocentric chromosomes was highly significantly increased. This surplus was not only caused by a highly significant increase of associating G chromosomes but also of D chromosomes. The loss of further acrocentric chromosomes had no significant influence on the number of mitoses with associations or the number of associating chromosomes. Based on the well-known correlations between the nucleolus organization and the association pattern, the results seem to indicate a compensation mechanism among the nucleoles organizing regions (NOR's) which keeps the supply of nucleolar material constant and simultaneously causes a higher association tendency between the remaining acrocentric chromosomes. The increase of associations in the 22 monosomic cells was interpreted as a overcompensation after the loss of only one NOR.

Cell Cycle↗
PubMed1989

Definition of mouse chromosome 1 and 3 gene linkage groups that are conserved on human chromosome 1: evidence that a conserved linkage group spans the centromere of human chromosome 1.

Comparative mapping between the human and the mouse genomes allows characterization of linkage groups that have been conserved over evolution. In this study, genes previously localized to adjacent regions of human chromosome 1 were mapped to discrete regions on distal mouse chromosomes 1 and 3 using an interspecific cross. Linkage analysis in mouse defined two groups in which the gene order appears to be the same as that in humans: 15 genes localized between human chromosome 1q21 and 1q32 were found to span 29.5 cM on distal mouse chromosome 1; 6 genes localized between human chromosome 1q21 and 1p22 spanned 15.6 cM on distal mouse chromosome 3. These data suggest that gene order within large chromosome segments may remain stable over long periods of evolution and that the position of the centromere may reflect a late event in the evolution of higher eukaryotic organisms. These studies provide a model for examination of specific evolutionary events.

Animals↗
PubMed1993

Balanced complex rearrangement involving chromosomes 8, 9, and 12 in a normal mother, derivative chromosome 9 with recombinant chromosome 12 in her daughter with minor anomalies.

We report on a 19-month-old girl with a derivative chromosome 9 and a recombinant chromosome 12 resulting from a maternal balanced complex rearrangement involving chromosomes 8, 9, and 12. The karyotype of the phenotypically normal mother was 46,XX,t(8;12) (9;12) (8qter-->8p23::12q12-->12q 15::9q32-->9qter;9pter-->9q32::12q15--> 12qter; 12pter-->12q12::8p23-->8pter). The child's karyotype was 46,XX,-9,-12, +der(9) (9pter-->9q32::12q15-->12qter), +rec(12) (12pter-->12q15::9q32-->9qter) mat. The child had severe growth retardation, minor anomalies including trigonocephaly, hypertelorism, broad nasal root, apparently low-set and posteriorly angulated ears, triangular face, pectus carinatum, clinodactyly of fifth fingers, and almost normal psychomotor development. To the best of our knowledge, there have been only 3 previous reports of recombination derived from parental complex chromosome rearrangements. In the recombination products, the chromosomes were apparently balanced and the offspring had no clinical abnormalities. The present case exhibited abnormalities and may have a submicroscopic aberration of 12q arising from crossing over during maternal meiotic pairing, although her chromosomes appeared to be balanced.

Abnormalities, Multiple↗