Showing papers on "Chromosome published in 1985"

Involvement of the bcl-2 gene in human follicular lymphoma

Abstract: Recombinant DNA probes were cloned for the areas flanking the breakpoint on chromosome 18 in cells from a patient with acute lymphocytic leukemia of the B-cell type; cells of this line carry the t(14;18) chromosomal translocation. Two of the probes detected DNA rearrangements in approximately 60 percent of the cases of follicular lymphoma screened. In follicular lymphoma, most of the breakpoints in band q21 of chromosome 18 were clustered within a short stretch of DNA, approximately 2.1 kilobases in length. Chromosome 18-specific DNA probes for the areas flanking the breakpoints also detected RNA transcripts 6 kilobases in length in various cell types. The gene coding for these transcript (the bcl-2 gene) seems to be interrupted in most cases of follicular lymphomas carrying the t(14;18) chromosomal translocation.

Nucleotide sequence of a t(14;18) chromosomal breakpoint in follicular lymphoma and demonstration of a breakpoint-cluster region near a transcriptionally active locus on chromosome 18

Abstract: The t(14;18)(q32;21) chromosomal translocation characteristic of follicular lymphomas is the most common cytogenetic abnormality known to be associated with any specific type of hematolymphoid malignancy. A fragment of DNA containing the crossover point between chromosomes 14 and 18 was cloned from the tumor cells of a patient with a follicular lymphoma carrying this translocation. Nucleotide sequence analysis of the breakpoint DNA revealed that the break in chromosome 14 occurred in joining region 4(J4) of the nonfunctional immunoglobulin heavy chain allele. This finding and other structural similarities of the breakpoint with the functional diversity region-joining region (D-J) joint in this lymphoma suggest that D-J recombination enzymes played a role in the mechanism of the t(14;18) translocation. Hybridization analysis of DNA from 40 follicular lymphomas showed that the majority of t(14;18) translocations occur on chromosome 18 DNA within 4.2 kilobases of the cloned breakpoint. A DNA probe from this breakpoint-cluster region detects transcription products in the tumor cells from which it was cloned and in a B-lymphoma cell line containing a t(14;18) translocation.

Differential activity of maternally and paternally derived chromosome regions in mice

Abstract: Although both parental sexes contribute equivalent genetic information to the zygote, in mammals this information is not necessarily functionally equivalent. Diploid parthenotes possessing two maternal genomes are generally inviable, embryos possessing two paternal genomes in man may form hydatidiform moles, and nuclear transplantation experiments in mice have shown that both parental genomes are necessary for complete embryogenesis. Not all of the genome is involved in these parental effects, however, because zygotes with maternal or paternal disomy for chromosomes 1, 4, 5, 9, 13, 14 and 15 of the mouse survive normally. On the other hand, only the maternal X chromosome is active in mouse extraembryonic membranes, maternal disomy 6 is lethal, while non-complementation of maternal duplication/paternal deficiency or its reciprocal for regions of chromosome 2, 8 and 17 has been recognized. We report that animals with maternal duplication/paternal deficiency and its reciprocal for each of two particular chromosome regions show anomalous phenotypes which depart from normal in opposite directions, suggesting a differential functioning of gene loci within these regions. A further example of non-complementation lethality is also reported.

An electrophoretic karyotype for yeast

Abstract: The chromosomal DNA molecules of a standard laboratory strain of Saccharomyces cerevisiae have been separated into 12 well-resolved bands by orthogonal-field-alternation gel electrophoresis. DNA X DNA hybridization probes derived from cloned genes have been used to correlate this banding pattern with yeast's genetically defined chromosomes. The 12 bands are shown to represent 9 singlets and 3 comigrating doublets, thereby accounting for 15 chromosomes that were identified as I-XI and XIII-XVI. Because the three comigrating doublets could be readily resolved in certain laboratory yeast strains that contain chromosome-length polymorphisms relative to our standard strain, all 15 of these chromosomes could be displayed as a single band in at least one of four strains that were studied. A 16th chromosome (number XII), which is known to contain the genes for rRNA, does not reproducibly enter the gels. By making use of the band identifications, the previously unmapped fragment F8 was assigned to chromosome XIII. With the possible exception of chromosomes that differ greatly in size or electrophoretic behavior from all the known chromosomes, the results appear to define a complete "electrophoretic karyotype" for yeast.

Localization of topoisomerase II in mitotic chromosomes.

Abstract: In the preceding article we described a polyclonal antibody that recognizes cSc-1, a major polypeptide component of the chicken mitotic chromosome scaffold. This polypeptide was shown to be chicken topoisomerase II. In the experiments described in the present article we use indirect immunofluorescence and immunoelectron microscopy to examine the distribution of topoisomerase II within intact chromosomes. We also describe a simple experimental protocol that differentiates antigens that are interspersed along the chromatin fiber from those that occupy restricted domains within the chromosome. These experiments indicate that the distribution of the enzyme appears to be independent of the bulk chromatin. Our data suggest that topoisomerase II is bound to the bases of the radial loop domains of mitotic chromosomes.

Clustering of breakpoints on chromosome 11 in human B-cell neoplasms with the t(11;14) chromosome translocation.

Abstract: The t(11;14) (q13;q32) chromosome translocation has been reported in diffuse small and large cell lymphomas and in chronic lymphocytic leukaemia (B-CLL) and multiple myeloma. Because chromosome band 14q32 is involved in this translocation, as well as in the t(8;14) (q24;q32) translocation of the Burkitt tumour, interruption of the immunoglobulin heavy-chain locus was postulated for this rearrangement. We have cloned the chromosomal joinings between chromosomes 11 and 14 and also between chromosomes 14 and 18, in B-cell tumours carrying translocations involving these chromosomes, and suggested the existence of two translocated loci, bcl-1 and bcl-2, normally located on chromosomes 11 (band q13) and 18 (band q21) respectively, involved in the pathogenesis of human B-cell neoplasms. The results indicate that in the leukaemic cells from two different cases of CLL, the breakpoints on chromosome 11 are within 8 nucleotides of each other and on chromosome 14 involve the J4-DNA segment. Because we detected a 7mer-9mer signal-like sequence with a 12-base-long spacer on the normal chromosome 11, close to the breakpoint, we speculate that the t(11;14) chromosome translocation in CLL may be sequence specific and may involve the recombination system for immunoglobulin gene segment (V-D-J) joining.

Loss of genes on the short arm of chromosome 11 in bladder cancer

Abstract: Recent studies have shown that normal cellular sequences on chromosome 13 are lost during the development of retinoblastomas and that sequences on chromosome 11 are similarly lost during the development of Wilms' kidney tumours and embryonal tumours. Cells from these tumors have been found to contain either the paternal or maternal copies of loci on the affected chromosome, but not both. Thus, the somatic loss of heterozygosity for sequences on chromosome 13 or 11 is hypothesized to result in homozygosity for a recessive mutant allele on these chromosomes, and in this way the chromosomal loss may contribute to the development of these tumours. We sought to investigate whether similar losses of heterozygosity for chromosome 11 sequences occurred in a common adult tumour. We chose to analyse bladder cancers, since such cancers are common in the adult population and are derived from urogenital tissue, as are Wilms' tumours. We examined constitutional and tumour genotypes at loci on the short arm of chromosome 11 (11p) in 12 patients with transitional cell carcinomas. In five tumours, we observed the somatic loss of genes on 11p resulting in homozygosity or hemizygosity of the non-deleted alleles in the tumour cells. Our results show that the frequency of loss of 11p sequences in bladder cancer approaches that seen in Wilms' tumour (42% compared with 55%), and suggest that recessive genetic changes involving sequences on 11p may contribute to the development of bladder neoplasms.

Construction of linkage maps with DNA markers for human chromosomes

Abstract: DNA markers and sampling of three-generation families can be used to construct complete linkage maps of human chromosomes. This is important in mapping disease loci and in determining the genetic or environmental component of a disease.

DNA probe localization at 18p113 band by in situ hybridization and identification of a small supernumerary chromosome

Abstract: Recombinant plasmid clone B74 (also named D18S3) containing a human single-copy DNA segment of 6 kilobases (kb) was localized by in situ hybridization on band p113 of chromosome 18. This probe was then used in cytogenetic diagnosis to identify precisely a small supernumerary chromosome as an isochromosome i(18p).

Individual interphase chromosome domains revealed by in situ hybridization

Abstract: The position and arrangement of individual chromosomes in interphase nuclei were examined in mouse-human cell hybrids by in situ hybridization of biotinylated human DNA probes. Intense and even labeling of human chromosomes with little background was observed when polyethylene glycol and Tween-20 were included in hybridization solutions. Human interphase chromosomes were separated from each other in the nucleus, and were confined to well localized domains. Hybrid cells with a single human chromosome showed a reproducible position of this chromosome in the nucleus. Some chromosomes appeared to have a characteristic folding pattern in interphase. Optical section as well as electron microscopy of labeled regions revealed the presence of 0.2 μm wide fibers in each interphase domain, as well as adjacent, locally extended 500 nm fibers. Such fibers are consistent with previously proposed structural models of interphase chromosomes.

Gene for alpha-chain of human T-cell receptor: location on chromosome 14 region involved in T-cell neoplasms

Abstract: A human complementary DNA clone specific for the alpha-chain of the T-cell receptor and a panel of rodent X human somatic cell hybrids were used to map the alpha-chain gene to human chromosome 14 in a region proximal to the immunoglobulin heavy chain locus. Analysis by means of in situ hybridization of human metaphase chromosomes served to further localize the alpha-chain gene to region 14q11q12, which is consistently involved in translocations and inversions detectable in human T-cell leukemias and lymphomas. Thus, the locus for the alpha-chain T-cell receptor may participate in oncogene activation in T-cell tumors.

Hypervariable telomeric sequences from the human sex chromosomes are pseudoautosomal

Abstract: Pairing of human X and Y chromosomes during meiosis initiates within the so–called pairing region at the telomeres or the chromosome short arms. Using DNA from the Y chromosome we found sequence homology in the pairing region of the human X and Y chromosomes. This DNA is telomeric, contains repetitive sequences and is highly polymorphic in the population. The polymorphism has allowed family studies which show the sequences are not inherited as though linked to the sex chromosomes. This ‘pseudoautosoma’ pattern of inheritance points to an obligate recombination in the pairing region of the sex chromosomes during male meiosis.

RNA-mediated gene duplication: the rat preproinsulin I gene is a functional retroposon.

Abstract: Rats and mice have two, equally expressed, nonallelic genes encoding preproinsulin (genes I and II). Cytological hybridization with metaphase chromosomes indicated that both genes reside on rat chromosome I but are approximately 100,000 kilobases apart. In mice the two genes reside on two different chromosomes. DNA sequence comparisons of the gene-flanking regions in rats and mice indicated that the preproinsulin gene I has lost one of the two introns present in gene II, is flanked by a long (41-base) direct repeat, and has a remnant of a polydeoxyadenylate acid tract preceding the downstream direct repeat. These structural features indicated that gene I was generated by an RNA-mediated duplication-transposition event involving a transcript of gene II which was initiated upstream from the normal capping site. Sequence divergence analysis indicated that the pair of the original gene and its retroposed, but functional, counterpart (which appeared about 35 million years ago) is maintained by strong negative selection operating primarily on the segments encoding the chains of the mature hormone, whereas the segments encoding the parts of the polypeptide that are eliminated during processing and also the introns and the flanking regions are evolving neutrally.

Specific staining of human chromosomes in Chinese hamster x man hybrid cell lines demonstrates interphase chromosome territories.

Abstract: In spite of Carl Rabl's (1885) and Theodor Boveri's (1909) early hypothesis that chromosomes occupy discrete territories or domains within the interphase nucleus, evidence in favor pf this hypothesis has been limited and indirect so far in higher plants and animals. The alternative possibility that the chromatin fiber of single chromosomes might be extended throughout the major part of even the whole interphase nucleus has been considered for many years. In the latter case, chromosomes would only exist as discrete chromatin bodies during mitosis but not during interphase. Both possibilities are compatible with Boveri's well established paradigm of chromosome individuality. Here we show that an active human X chromosome contained as the only human chromosome in a Chinese hamster x man hybrid cell line can be visualized both in metaphse plates and in interphase nuclei after in situ hybridization with either 3H- or biotin-labeled human genomic DNA. We demonstrate that this chromosome is organized as a distinct chromatin body throughout interphase. In addition, evidence for the territorial organization of human chromosomes is also presented for another hybrid cell line containing several autosomes and the human X chromosome. These findings are discussed in the context of our present knowledge of the organization and topography of interphase chromosomes. General applications of a strategy aimed at specific staining of individual chromosomes in experimental and clinical cytogenetics are briefly considered.

In vivo effects of cis- and trans-diamminedichloroplatinum(II) on SV40 chromosomes: differential repair, DNA-protein cross-linking, and inhibition of replication.

Abstract: The mechanism of action of the antitumor drug cis-diamminedichloroplatinum(II), cis-DDP, was investigated by using the approximately 5200 base pair (bp) chromosome of simian virus 40 (SV40) as an in vivo chromatin model. Comparative studies were also carried out with the clinically ineffective isomer trans-DDP. Although 14 times more trans- than cis-DDP in the culture medium is required to inhibit SV40 DNA replication in SV40-infected green monkey CV-1 cells, the two isomers are equally effective at inhibiting replication when equimolar amounts are bound to SV40 DNA in vivo. Since both isomers are transported into CV-1 cells at similar rates, differential uptake cannot account for the greater ability of cis-DDP to inhibit SV40 DNA replication. Rather, this result is explained by the finding that cis-DDP-DNA adducts accumulate continuously over the incubation period, whereas trans-DDP binding to DNA reaches a maximum at 6 h and thereafter decreases dramatically. We suggest that the different accumulation behavior of cis-DDP and trans-DDP on DNA is due to their differential repair in CV-1 cells. A variety of non-histone proteins, including SV40 capsid proteins but virtually no histones, are cross-linked to SV40 DNA in vivo by either cis- or trans-DDP. More DNA-protein cross-links are formed by trans-DDP than by cis-DDP at equivalent amounts of DNA-bound platinum.(ABSTRACT TRUNCATED AT 250 WORDS)

Size variation in chromosomes from independent cultured isolates of Plasmodium falciparum.

Abstract: The complexity of the life cycle of the protozoan malaria parasite Plasmodium falciparum has hindered genetic analysis1; even the number of chromosomes in P. falciparum is uncertain2. The blood stages of rodent malaria parasites are haploid1,3 and hybridization with cloned complementary DNAs similarly suggests a haploid genome in P. falciparum blood stages (ref. 4 and our unpublished results). A novel approach to karyoptic and linkage analysis in P. falciparum has been provided recently by the technique of pulsed-field gradient (PFG) gel electrophoresis5, which allows the fractionation of DNA molecules of 30–3,000 kilobases (kb), a range including the sizes of intact chromosomal DNA molecules from eukaryotes such as yeast5 and trypanosomatids6. We describe here the fractionation by PFG electrophoresis of chromosomal DNA molecules from P. falciparum into at least seven discrete species which vary in size by up to 20% between different isolates. Several genes for P. faciparum antigens which contain repetitive sequences are located on different chromosomes. Surprisingly, two of the chromosomes seem to contain the same sequences.

Mutants of Schizosaccharomyces pombe which sporulate in the haploid state.

Abstract: Suppressor mutants of mei1–102, a mutation in one of the mating type cassette genes (mat2-P) which blocks the progression into meiosis, were isolated and characterized in Schizosaccharomyces pombe. These suppressor mutations conferred either temperature-sensitivity or cold-sensitivity. The growth of these strains is halted and sporulation initiated at the restrictive temperatures, regardless of other conditions usually required for the initiation of meiosis i.e. they sporulate in the presence of a nitrogen source and mating type homozygosity. Their most striking feature is that they can sporulate from the haploid state. The haploidy of these mutants was confirmed by genetical analysis and by measurement of the DNA content of the cells. The mutants are all recessive and define a single gene pat1. The pat1 gene maps very close to the centromere of chromosome II. A meiosis defective mutation in mei5 can suppress the temperature-sensitivity caused by pat1, indicating some interaction between them. Spores produced from a haploid cell have poor viability and appear to contain only 1/2C DNA on average.

Chromosome Segregation in Mitosis and Meiosis

Abstract: A MODEL FOR CHROMOSOME BEHAVIOR DURING MITOSIS AND MEIOSIS .................................... .. The Mitotic Cell Cycle .....................................................................•............................................ Interphase ........................................................................................................................................ . Metaphase .......................................................................•................................................................. Anaphase .......................................................................................................................................... . Meiosis .................................................................................................•...............................................

The evolutionary history of Drosophila buzzatii IX. High frequencies of new chromosome rearrangements induced by introgressive hybridization

Abstract: Introgression of a chromosome segment from Drosophila serido into the genome of its sibling D. buzzatii brought about the release of mutator potential in the hybrids. Mutator activity was determined by examining the frequency of new chromosomal rearrangements, that appeared only in the progeny of hybrid individuals. Mutation frequency was 30 times greater in the progeny of hybrid males than in that of hybrid females. There was a remarkable influence of the D. buzzatii genetic background on the frequency of production of these new rearrangements. The appearance of a new rearrangement did not depend on the genotype of the larva that bore it, but only on that of its hybrid progenitor. Among the new rearrangements there were inversions, translocations, and duplications. The number of translocations was significantly lower than that of inversions or duplications; this last type was the most frequently recorded. The distribution of the aberrations among the four major autosomes seemed to be homogeneous, although the total number of breakpoints was significantly greater in chromosome 4 than in the others. No rearrangement was found on the X chromosome. Breakpoints within three of the four affected autosomes were not randomly distributed.

Pseudoautosomal DNA sequences in the pairing region of the human sex chromosomes.

Abstract: A DNA probe from a human Y chromosome-derived cosmid detects a single-copy genomic DNA fragment which can appear in different allelic forms shared by both sex chromosomes Variants at this DNA locus show an autosomal pattern of inheritance, undergo recombination with sexual phenotype and can therefore be described as ‘pseudoautosomal’ Another probe from the same cosmid detects a sequence repeated 15–20 times per haploid genome These repeats also appear pseudoautosomal and map exclusively to the short-arm terminal region of each sex chromosome

A human Y-linked DNA polymorphism and its potential for estimating genetic and evolutionary distance.

Abstract: A human DNA sequence (p12f2), derived from a partial Y-chromosome genomic library and showing homology with the X and Y chromosomes and with an undetermined number of autosomes, detected two Y-specific restriction fragment length variants on male DNA that had been digested with Taq I and Eco RI. These variants may have been generated through a deletion-insertion mechanism and their pattern of holoandric transmission indicates that they represent a two-allele Y-linked polymorphism (RFLP). By means of DNA from patients with inborn deletions in chromosome Y, this polymorphic DNA site was mapped to the interval Yq11.1-Yq11.22. The frequency of the rarest allele was about 35 percent in Algerian and Sardinian human males, whereas it was only 4 percent among Northern Europeans. The p12f2 probe also detected Y-specific DNA fragments in the gorilla and chimpanzee. In view of the monosomy of the Y chromosome in mammalian species, Y-linked RFLP's may prove to be more useful than autosomal or X-linked markers in estimating genetic distances within and between species.

Mutant genes affecting higher plant meiosis.

Abstract: That meiosis is conditioned by a large number of genes majority of which are present in a dominant state, is evidenced by the detection of numerous monogenic recessive mutant genes which affect the premeiotic, meiotic and post-meiotic course of events. These genes are site- and stage-specific, and a few are sex specific. Of these, the most prevalent are the mutant genes affecting male meiosis and causing male sterility (ms genes) and those inhibiting synapsis and chiasma formation (synaptic genes) and leading to gametic sterility. Majority of the mutant genes affect the entire chromosomal complement but a few influence only specific chromosomes of a complement so that the chromosomes behave differentially within a genome of the same species. Some mutant genes alter chromosome form and function, others modify integrity, degree of spiralization, movement and migration of chromosomes. Their cytogenetic behaviour, genetic significance and breeding utility are described and discussed.

Chromosome-sized DNA molecules of Plasmodium falciparum

Abstract: At least seven chromosome-sized DNA molecules (750 to 2000 kilobases in length and one fraction of undetermined molecular weight) from cultured clones and isolates of Plasmodium falciparum have been separated by pulsed-field gradient gel electrophoresis Whereas asexual blood stages and sexual stages of the same line have identical molecular karyotypes, the length of chromosome-sized DNA molecules among different geographical isolates and several clones derived from a single patient is different These length alterations of chromosomes are the result of DNA rearrangements that must occur unrelated to sexual differentiation

Human genes involved in cholesterol metabolism: chromosomal mapping of the loci for the low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl-coenzyme A reductase with cDNA probes

Abstract: Cellular cholesterol metabolism is regulated primarily through the coordinate expression of two proteins, the low density lipoprotein (LDL) receptor and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (EC 1.1.1.34). We have used cDNA probes for the human genes encoding these proteins to determine the precise chromosomal location of the two loci. By in situ hybridization we have regionally mapped the LDL receptor gene, LDLR, to the short arm of chromosome 19 in bands p13.1-p13.3. This result concurs with and extends a previous study in which LDLR was mapped to chromosome 19 by screening somatic cell hybrids with a species-specific monoclonal antibody. We have assigned the HMG-CoA reductase gene, HMGCR, to chromosome 5 by Southern blotting of DNA from a somatic cell hybrid panel and to bands 5q13.3-q14 by in situ hybridizations of the cDNA probe to human metaphase cells with normal and rearranged chromosomes.

Identification and chromosomal distribution of 5S rRNA genes in Neurospora crassa.

Abstract: The 5S rRNA genes of Neurospora crassa, unlike those of most organisms, are not tandemly arranged, and they are found imbedded in a variety of unique sequences. The 5S rRNA regions of most of the genes are of one type, alpha; however, several other "isotypes" (beta, gamma, delta, zeta, and eta) are also found. We asked whether Neurospora 5S rRNA genes are dispersed on a chromosomal scale and whether genes of different isotypes are spatially segregated. We identified, by DNA sequencing, 5S rRNA genes in 22 5S DNA clones, and we mapped these genes by conventional crosses by using restriction fragment length polymorphisms in their flanking sequences as genetic markers. The results show that the 5S rRNA genes are distributed on at least six of the seven chromosomes. Their location does not appear to be completely random. Some of them are closely linked. One of the chromosomes carries a disproportionate number of 5S rRNA genes of the most common structural type, alpha; another chromosome carries three of the four mapped beta 5S rRNA genes. None of the 5S rRNA genes studied maps close to the nucleolus organizer, the site of the genes that code for the three larger rRNAs.