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At least 1,243 records · Page 69Linked to original sources
PubMed1997

Transmission electron microscopy of chromosomes by longitudinal section preparation: application to fragile X chromosome analysis.

We developed a method for the preparation of ultrathin longitudinal sections of chromosomes enabling TEM studies of whole chromosomes. By using a novel "repeat chill" method of exposing the glass slide and plastic block interface to liquid nitrogen, it was possible to separate consistently hardened epoxy resin-embedded chromosome spreads from glass slides for ultrathin longitudinal sectioning of entire spreads and of individual chromosomes. The method was applied to analyze the fragile X chromosome. The ultrastructure of centromeres, telomeres, fragile sites and other chromosomal areas can now be studied in detail.

Centromere↗
PubMed1999

Contact zones between chromosomal races of Mus musculus domesticus. 1. Temporal analysis of a hybrid zone between the CD chromosomal race (2n=22) and populations with the standard karyotype.

A temporal analysis of a hybrid zone between chromosomal races of Mus musculus domesticus was performed to evaluate its dynamics over a 20-year period. The transect chosen was one previously analysed by Spirito et al. (1980) across the hycbrid zone between the chromosomal race CD 2n=22 (central Italy) and the surrounding populations with standard karyotype (2n=40). The results show that 20 years of hybridization have not had any significant effect on the position of this hybrid zone, nor on the location of its extreme margin, except for one site for which passive transport of mice may have been important. The absence of a significant shift of the tension zone excludes a possible imbalance between the two cytotypes; a fitness superiority of one homozygote greater than 0.01 would have produced an appreciable shift of the zone. The internal chromosomal structure of the zone shows a constant gradual increase in metacentric chromosome frequency towards the localities nearest the area inhabited by the 22-CD homozygote population. This contrasts with the previously reported data which indicated an irregular trend, particularly evident for the Rb(3.8), Rb(5.17) and Rb(6.13) chromosomes. For each Rb metacentric, we observed greater values of FST in the past sample than in the present one. These differences reveal a tendency towards the homogenization of adjacent populations, perhaps because of greater migration between adjacent demes resulting from increased commercial traffic. The Mantel test was performed for both temporal samples. A positive correlation between the geographical and chromosomal differentiation was demonstrated.

Animals↗
PubMed1999

Chromosome mapping in Cryptosporidium parvum and establishment of a long-range restriction map for chromosome VI.

We used contour-clamped homogeneous electric field (CHEF) gel electrophoresis and Southern blot hybridization to analyze the molecular karyotype of Cryptosporidium parvum and establish the chromosomal location of 12 single copy genes. In agreement with previous studies, the molecular karyotype of C. parvum was found to consist of partially co-migrating chromosomes ranging in size from 0.97 to 1.55 Mb and segregating into five distinct electrophoretic bands. Hybridization results allowed the definition of a linkage group comprised of five distinct loci located on chromosome VI. Southern hybridization and restriction analysis of total C. parvum chromosomes or isolated chromosome VI using gene-specific probes and an oligonucleotide specific for C. parvum telomeres allowed the development of a long-range restriction map of chromosome VI.

Animals↗
PubMed1984

Video digitizer analysis of birefringence along the lengths of single chromosomal spindle fibres. II. Crane-fly spermatocyte chromosomal spindle fibres are not temperature-labile.

Retardations were measured along the lengths of single chromosomal spindle fibres, from metaphase through anaphase, from video-taped images of crane-fly spermatocytes incubated at various temperatures (4-30 degrees C). These measurements were made using a video digitizer interfaced to a microcomputer. Over most of the range of temperatures at which normal anaphase movement occurs the chromosomal spindle fibres are not temperature-labile. The non-specific and continuous fibre birefringence is temperature-labile, however. The data are discussed with respect to the 'dynamic equilibrium' model of anaphase chromosome movement. We conclude that, since single chromosomal fibre birefringence is not temperature-labile over most of the range of temperatures at which normal anaphase chromosome movement occurs, these data do not support the dynamic equilibrium model of anaphase chromosome movement.

Anaphase↗
PubMed1987

[Genetic study of plasmid integration into yeast chromosomes. IV. Integration of the plasmid pYF91 into different yeast chromosomes].

Integration of the episomic chimeric plasmid pYF91 into yeast chromosomes has been studied. Plasmid insertion into the chromosomes was observed to occur with the frequency of 4 X 10(-8). 379 integrants were selected from the highly unstable (cir0) transformants. The fact of plasmid integration into particular chromosomes was confirmed for 318 integrants. Genetic analysis showed that the plasmid can integrate into the region of LEU2 gene or into another arm of chromosome III (227 integrants), and also into other chromosomes: I, II, IV, V, VI, VII, VIII, IX, XII, XV (91 integrants). It is suggested that integration is the result of recombination between yeast chromosomes and homologous plasmid regions carrying LEU2 gene or Ty element and "delta" sequence.

DNA, Fungal↗
PubMed1994

[Identification of marker chromosomes and complex chromosomal translocations, using non radioactive in situ hybridization, in malignant hemopathies].

We describe five patients with hematological malignancies in which fluorescence in situ hybridization technique (FISH) has been combined with classical cytogenetic study for characterizing chromosomal abnormalities. Three of them were chromosome Philadelphia positive; using a 22 chromosome painting probe it was confirmed the presence or absence of a variant complex translocation. In patients 4 and 5, the karyotype showed a marker chromosome which was definitively identified by FISH as a deletion of X chromosome and a 18 ring chromosome, respectively. The value of this methodology in the cytogenetic diagnosis of hematological malignancies is commented.

Aged↗
PubMed1996

Aneuploid epididymal sperm detected in chromosomally normal and Robertsonian translocation-bearing mice using a new three-chromosome FISH method.

We present a new method to detect epididymal sperm aneuploidy (ESA) in mice using simultaneous fluorescence in situ hybridization (FISH) with DNA probes specific for mouse chromosomes X, Y and 8. The method was applied to Robertsonian (Rb) translocation (8.14) heterozygotes and homozygotes as well as the chromosomally normal B6C3F1. The sex ratios of sperm did not differ from the expected 1:1 and the hybridization efficiencies were approximately 99.7% for over 60 000 sperm analyzed. Mice heterozygous for Rb (8.14) produced about tenfold higher rates of sperm with chromosome 8 hyperhaploidy than did Rb (8.14) homozygotes or chromosomally normal mice, while frequencies of sperm with hyperhaploidies for chromosomes X and Y were unaffected in all three lines of mice. Hyperhaploid frequencies obtained with the ESA method were consistent with those of the previous testicular FISH method and were validated by published data obtained by conventional cytogenetic analyses (meiotic metaphase II and first cleavage). Thus, the mouse three-chromosome ESA assay together with the previously developed aneuploidy assay for human sperm constitute a promising pair of interspecific biomarkers for comparative studies of the genetic and physiologic mechanisms of the induction and persistence of aneuploidy in male germ cells.

Aneuploidy↗
PubMed1984

Cat-eye syndrome with unusual marker chromosome probably not chromosome 22.

An unusual supernumerary chromosome with a single satellite on the long arm was found in a child with manifestations of the cat-eye syndrome including apparently low-set and malformed ears, preauricular tags, micrognathia, and imperforate anus. Although G-banding suggested that this extra material was chromosome 22, this was not confirmed by several other banding techniques. After examination of the parents' chromosomes, the nature and origin of this extra chromosome remains obscure. We conclude that patients previously diagnosed as having "partial trisomy 22" with incomplete cat-eye syndrome may have a different chromosome constitution when studied by various banding techniques.

Anus, Imperforate↗
PubMed1995

Mosaicism for a chromosome 8-derived minute marker chromosome in a patient with manifestations of trisomy 8 mosaicism.

We describe a patient with manifestations of the mosaic trisomy 8 syndrome and mosaicism for a minute marker chromosome. Fluorescence in situ hybridization (FISH) with a chromosome 8 probe confirmed that the marker was derived from chromosome 8. This is the smallest piece of chromosome 8 to be reported in a patient with mosaic trisomy 8 syndrome. When the clinical picture is strongly suggestive of trisomy for a specific chromosome region, we believe that FISH can be used to test markers in a guided, rather than random, fashion.

Chromosome Banding↗
PubMed2002

Maternal uniparental isodisomy 10 and mosaicism for an additional marker chromosome derived from the paternal chromosome 10 in a fetus.

We report a case of maternal isodisomy 10 combined with mosaic partial trisomy 10 (p12.31-q11.1). Chromosome examinations from a CVS sample showed a karyotype 47,XX,+mar/46,XX [corrected]. The additional marker chromosome which was present in 6/25 interphase nuclei was shown by fluorescence in situ hybridization (FISH) to have been derived from a pericentromeric segment of chromosome 10. DNA analysis was performed from umbilical cord blood from the fetus after termination of the pregnancy at 18 weeks. The results showed that the two structurally normal chromosomes 10 were both of maternal origin, whereas the marker chromosome derived from the father. Autopsy of the fetus revealed hypoplasia of heart, liver, kidneys and suprarenal glands, but, apart from a right bifid ureter, no structural organ abnormalities. This fetus represents the second reported instance of a maternal uniparental disomy (UPD) 10.

Abnormalities, Multiple↗
PubMed1994

Regional mapping of loci from human chromosome 2q to sheep chromosome 2q.

The human chromosome 2q loci, fibronectin 1 (FN1), the alpha 1 chain of type III collagen (COL3A1), and the delta subunit of the muscle acetylcholine receptor (CHRND) have been regionally assigned to sheep chromosome 2q by in situ hybridization. COL3A1 is pericentromeric (2q12-q21), while FN1 and CHRND are in the subterminal region at 2q41-q44 and 2q42-qter, respectively. The mapping of FN1 assigns the sheep syntenic group U11, which contains FN1, villin 1 (VIL1), isocitrate dehydrogenase 1 (IDH1), and gamma subunit of the muscle acetylcholine receptor (CHRNG), to sheep chromosome 2q. Inhibin-alpha (INHA) is also assigned to sheep chromosome 2q as FN1 and INHA compose sheep linkage group 3. These seven loci are members of a conserved chromosomal segment in human, mouse, and sheep.

Animals↗
PubMed1994

Isolation, chromosomal localization, and sequence analysis of human chromosome 21 zinc finger domains.

The zinc finger element is a conserved motif among a group of proteins involved in binding to nucleic acid. This motif has been detected in many regulatory factors and is highly represented in the human genome. To investigate the presence of zinc-finger-encoding genes on human chromosome 21, chromosome-specific libraries were screened with an oligodeoxynucleotide probe representing the conserved H-C link region between adjacent fingers. Three distinct genomic clones, designated ZF21-1, ZF21-2, and ZF21-3, were isolated and mapped to the long arm of chromosome 21 as well as to the heterochromatic short arm of several other chromosomes. DNA sequence analysis has shown that these genomic clones contain multiple zinc finger elements of the Kruppel type with only partial similarity to other known zinc finger genes. However, in each clone, few fingers were degenerated; they contain inframe stop codons and frameshifts that would preclude their translation. It seems therefore, that these chromosome 21 zinc finger sequences are not parts of functional genes. Nevertheless, the possibility that these domains are transcribed, and thus might have a regulatory role, is considered.

Animals↗
PubMed1994

Establishment of a partially informative porcine somatic cell hybrid panel and assignment of the loci for transition protein 2 (TNP2) and protamine 1 (PRM1) to chromosome 3 and polyubiquitin (UBC) to chromosome 14.

Porcine lymphocytes and fibroblasts were fused with 3 different permanent rodent cell lines, and 21 stable somatic cell hybrid lines were established. These hybrid cell lines were characterized cytogenetically by sequential QFQ banding and chromosome painting using fluorescence in situ hybridization with porcine DNA. The lines were further characterized by PCR analysis with primer pairs derived from genes with confirmed mapping information. Using this panel, we assigned the locus encoding polyubiquitin (UBC) to chromosome 14, and the transition protein 2 locus (TNP2) and protamine loci (PRM1 and PRM2) to chromosome 3. Two chromosomal localizations have been further refined by radioactive in situ hybridization. UBC maps to chromosome 14q12-q15 and TNP2 to 3p11-p12.

Animals↗
PubMed1994

Selection of chromosome 22-specific clones from human genomic BAC library using a chromosome-specific cosmid library pool.

A new approach to rapidly identify chromosome-specific subsets of clones from a total human genomic library is described. We report here the results of screening a human bacterial artificial chromosome (BAC) library using the total pool of clones from a chromosome 22-specific cosmid library as a composite probe. The human BAC library was gridded on filters at high density and hybridized with DNA from the pooled chromosome 22-specific Lawrist library under suppressive conditions. In a single hybridization, we picked 280 candidates from the BAC library representing over 30,000 clones (or 1.2x coverage of human genome). This subset contained more than 60% of the chromosome 22-specific BAC clones that were previously found to be present in the original BAC library. In principle, this approach can be applied to select a subset of clones from other global libraries with relatively large inserts using a pool from a regional library as a composite probe. It is important to note that the target and probe libraries must be based on vectors that share no homology with each other.

Chromosomes, Bacterial↗
PubMed1994

The fibulin-1 gene (FBLN1) is located on human chromosome 22 and on mouse chromosome 15.

Fibulin-1 is a calcium-binding glycoprotein present in the extracellular matrix and in the serum. The gene coding for fibulin-1 (FBLN1) was located by in situ hybridization of 3H-labeled cDNA probes to human and mouse metaphase chromosomes. The gene was assigned to the q13.2-q13.3 region of human chromosome 22 and to the E-F band of mouse chromosome 15. This finding extends the evolutionary conservation between human chromosome 22 and mouse chromosome 15.

Animals↗
PubMed1994

The mouse and human excitatory amino acid transporter gene (EAAT1) maps to mouse chromosome 15 and a region of syntenic homology on human chromosome 5.

The gene for human excitatory amino acid transporter (EAAT1) was localized to the distal region of human chromosome 5p13 by in situ hybridization of metaphase chromosome spreads. Interspecific back-cross analysis identified the mouse Eaat1 locus in a region of 5p13 homology on mouse chromosome 15. Markers that are linked with EAAT1 on both human and mouse chromosomes include the receptors for leukemia inhibitory factor, interleukin-7, and prolactin. The Eaat1 locus appears not to be linked to the epilepsy mutant stg locus, which is also on chromosome 15. The EAAT1 locus is located in a region of 5p deletions that have been associated with mental retardation and microcephaly.

Amino Acid Transport Systems↗
PubMed1994

A set of ninety-seven overlapping yeast artificial chromosome clones spanning the human Y chromosome euchromatin.

Contiguous arrays of yeast artificial chromosomes (YACs) extending from proximal heterochromatic Yq into the pseudoautosomal portion of the Y chromosome and separated by a small interval at the centromere have been constructed. A total of 97 YACs have been aligned along the Y chromosome by STS content analysis using 222 sequence tagged sites (STSs) that detect 263 loci. Forty-five of the STSs used are novel. Their inclusion provides a significant improvement over previously available maps on the density of STS coverage along the Y chromosome, reducing the average spacing to 120 kb assuming a length of 30 Mb for the euchromatin. The average size of 61 YACs determined by pulsed-field gel electrophoresis analysis was at least 0.9 Mb. Minor differences noted between the ordering of STSs on this map compared with those previously reported may be attributed to inherent polymorphism between the Y chromosomes used to construct the YAC libraries.

Base Sequence↗
PubMed1996

The gene for calcium-modulating cyclophilin ligand (CAMLG) is located on human chromosome 5q23 and a syntenic region of mouse chromosome 13.

The CAMLG gene encodes a novel cyclophilin B-binding protein called calcium-modulating cyclophilin ligand, which appears to be involved in the regulation of calcium signaling in T lymphocytes and other cells. The murine homolog, Caml, was localized by interspecific backcross analysis to the middle of chromosome 13. By fluorescence in situ hybridization, this gene was localized to human chromosome 5 in a region (q23) known to be syntenic to mouse chromosome 13. These results provide further evidence supporting the extensive homology between human chromosome 5q and mouse chromosome 13. In addition, the results will provide a basis for further evaluation of cytogenetic anomalies that may contribute to inherited defects in calcium signaling or immune system function.

Adaptor Proteins, Signal Transducing↗