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Definitive chromosomal location of the H-2 complex by in situ hybridization to pachytene chromosomes.

Chromosome 17 of the mouse carries the H-2 complex and the T/t complex. An understanding of the organization of this region and an accurate genetic map of chromosome 17 would be of great value for both immunologists and developmental biologists. Until now the only maps available have been derived solely from recombinational studies using several translocations, an inherently inaccurate method. We have found the definitive location of the H-2 complex by the use of in situ hybridization. Our results show that both the T/t complex and the H-2 complex map to positions far more distal than the generally accepted map positions. This proves that recombination in Robertsonian chromosomes underestimates physical map distances on chromosome 17.

Animals↗

Poly(ADP-ribose) polymerase gene on chromosome 1q: early role in differentiation linked replication; gene on human chromosome 13q: marker of carcinogenesis.

We have focused in part on utilizing molecular aspects of the PADPRP gene sequences located on chromosome 1q as well as on 13 to help clarify the biological role of these genes. With respect to chromosome 1q, stably transfected cell lines have been established in-both HeLa as well as 3T3-L1 preadipocyte cells, which express a reverse complementary transcription product in vivo to the exons coded for on the chromosome 1 locus. Also, in the case of the PADPRP-like gene on chromosome 13q, we have fine mapped this sequence and have observed in a linkage of deletion of this region with predisposition to various forms of cancer, especially in the African-American population.

3T3 Cells↗

The serotonin receptor subtype 2 locus HTR2 is on human chromosome 13 near genes for esterase D and retinoblastoma-1 and on mouse chromosome 14.

Serotonin (5-hydroxytryptamine) functions as a neurotransmitter and a hormone. Its diverse actions are mediated by at least seven distinct cell surface receptor subtypes. The serotonin receptor subtype 2 (gene symbol HTR2) is a G-protein-coupled receptor, expressed primarily in the cerebral cortex, where upon stimulation it stimulates the hydrolysis of inositol phospholipids. We have mapped the HTR2 locus to human chromosome 13 and to mouse chromosome 14 by somatic cell hybrid analysis. Linkage studies in CEPH families, using a PvuII RFLP detected with the HTR2 probe, revealed tight linkage between HTR2 and ESD, the locus for esterase D. The most likely position for HTR2 is between ESD and RB1, the retinoblastoma-1 gene. The homologous loci in mouse, Rb-1 and Esd(Es-10) are on mouse chromosome 14, close to ag, agitans, a recessive neurological mutation. Having mapped Htr-2 to mouse chromosome 14, we predict that it falls into this known conserved gene cluster.

Animals↗

Assignment of the lactotransferrin gene to human chromosome 3 and to mouse chromosome 9.

Lactotransferrin (LTF), a member of the transferrin family of genes, is the major iron-binding protein in milk and body secretions. The amino acid sequence of LTF consists of two homologous domains homologous to proteins in the transferrin family. Recent isolation of cDNA encoding mouse LTF has expedited the mapping of both mouse and human LTF genes. Southern blot analysis of DNA from mouse-Chinese hamster and human-mouse somatic cell hybrids maps the LTF gene to mouse chromosome 9 and to human chromosome 3, respectively. Furthermore, analysis of cell hybrids containing defined segments of human chromosome 3 demonstrates that the gene is located in the 3q21-qter region. These results suggest that LTF and associated genes of the transferrin family have existed together on the same chromosomal region for 300-500 million years.

Animals↗

Assignment of gene for coagulation factor V to chromosome 1 in man and to chromosome 13 in rat.

Two different factor V cDNA fragments were used as hydridization probes in the chromosomal assignment of the human and rat factor V genes. A 1.6-kb EcoRI fragment was used as a hybridization probe to analyze a panel of human-rodent somatic cell hybrids. Cosegregation of factor V specific DNA restriction fragments with human chromosome 1 was observed. In addition, a panel of rat-mouse somatic cell hybrids was analyzed with another human factor V cDNA probe to localize the gene for rat coagulation factor V. In the rat, the gene for coagulation factor V was found to be located in chromosome 13. This is the first gene in the rat to be localized to chromosome 13.

Animals↗

Chromosomal localization of genes by scanning electron microscopy using in situ hybridization with biotinylated probes: Y chromosome repetitive sequences.

The feasibility of using scanning electron microscopy (SEM) to identify the position of specific DNA sequences was examined using a Y chromosome 'specific' probe (pHY2.1). Tests were carried out on chromosome spreads hybridized in situ with biotinylated pHY2.1. Chromosomal sites of hybridization of the probe were localized by an indirect immunohistochemical procedure which resulted in a gold product which could be amplified by silver precipitation. In the SEM, the specific location of the probe was easily identified due to the enhanced signal produced by the gold-silver complex. The probe was localized both on the long arm of the Y chromosome and within interphase nuclei. It was found that SEM was more sensitive than light microscopy since the probe could be identified without silver amplification. With refinements to the technique, SEM could provide a useful method for high resolution localizing of unique DNA sequences (i.e. single copy genes).

Biotin↗

Lampbrush W and Z heterochromosome characterization with a monoclonal antibody and heat-induced chromosomal markers in the newt Pleurodeles waltl: W chromosome plays a role in female sex determination.

Two subsets of lateral loops scattered on lampbrush chromosomes of the newt Pleurodeles waltl were characterized. One group was identified by labelling with a monoclonal antibody (A1). The second group was identified by the ability of the loops to be induced by heat treatment. Three loops of each subset were mapped on a short region of the two homologues of lampbrush bivalent IV. These regions appear to be heteromorphic because the six loops are always heterozygous. Five loops are found on one homologue and the sixth on the partner. The distribution of these markers in phenotypic females corresponding to the three sexual genotypes ZW, WW and ZZ shows an absolute correlation of the five loop group with the W chromosome and of the other loop with the Z chromosome. Therefore the heteromorphic regions of the homologues correspond to the differential segments of the heterochromosomes. The identification of a trisomic ZZW female suggests that the W chromosome bears female sex determinants. Furthermore the results show that heat induces loop development and that under normal conditions giant loop development is influenced by the sexual genotype.

Animals↗

Mapping QTLs for grain dormancy on wheat chromosome 3A and the group 4 chromosomes, and their combined effect.

A major QTL for grain dormancy, QPhs.ocs-3A.1, derived from the highly dormant wheat Zenkoujikomugi (Zen), has been identified in a study made under a controlled environment. Further investigations were needed to dissect the precise position and expression of QPhs.ocs-3A.1 under different field conditions because the ability to detect genetic loci for grain dormancy traits is compromised by environmental effects and genotype/environment interactions. Group 4 chromosomes have also been shown to be possible sites of QTLs for grain dormancy. The objectives of this study were (1) to locate additional molecular markers in the QPhs.ocs-3A.1 region, (2) to identify QTLs on the group 4 chromosomes and (3) to elucidate their combined effects. We examined the recombinant inbred lines (RILs) from a cross between Chinese Spring (CS) and Zen over a 3-year period in one location and 1 year in a different location. In an interval mapping study QPhs.ocs-3A.1 was mapped to within the 4.6 cM region flanked by Xbarc310 and Xbcd907 at the proximal end of the short arm of chromosome 3A. QPhs.ocs-3A.1 was confirmed to be the predominant dormancy QTL since it explained a large portion (11.6-44.8%) of the phenotypic variation, and was strongly displayed under dormancy-breaking conditions or at low germination temperatures. For QPhs.ocs-4A.1, identified on the long arm of chromosome 4A, and QPhs.ocs-4B.1, on the centromeric region of the long arm of Chr 4B, the LOD peak positions and the desirable allele were consistent between the trials, while the LOD scores and contribution to the phenotypic variation varied. Transgressive segregants were observed among the 125 RILs and most of them had a combination of the three alleles conferring a higher dormancy: the Zen alleles at QPhs.ocs-3A.1 and QPhs.ocs-4A.1 and the CS allele at QPhs.ocs-4B1. This demonstrated a combined effect of the desirable alleles on accelerating grain dormancy, with their total effect being superior to that of Zen.

Chromosome Mapping↗

Sex chromosome linkage of chicken and duck type I interferon genes: further evidence of evolutionary conservation of the Z chromosome in birds.

Type I interferons (IFNs) are a family of proteins that are predominantly expressed in response to viral infection. Two serologically distinct forms of type I IFN, designated ChIFN1 and ChIFN2, have recently been recognized in the chicken. ChIFN1 is encoded by a cluster of ten or more intronless genes, whereas ChIFN2, whose primary sequence is 57% identical, is encoded by a single intronless gene. By fluorescence in situ hybridization we now demonstrate that the genes for ChIFN1 and ChIFN2 are all located on the short arm of the chicken Z chromosome. This assignment was confirmed by results that showed that DNA from male (ZZ) chickens yielded approximately twofold stronger Southern blot signals with ChIFN1 and ChIFN2 hybridization probes than DNA from females (ZW). Attempts to determine differences in IFN production between male and female chickens failed owing to a high degree of variation in virus-induced IFN expression between individuals of both sexes. Sex linkage of IFN genes was also observed in domestic ducks: fluorescence in situ hybridization of duck metaphase chromosomes with a duck type I IFN probe was confined to the terminal region of the long arm of the Z chromosome. Thus, in contrast to mammals, which have their IFN genes on autosomes, birds have the type I IFN genes on the sex chromosome.

Animals↗

Hepatosplenic gammadelta T-cell lymphoma with ring chromosome 7, an isochromosome 7q equivalent clonal chromosomal aberration.

Hepatosplenic T-cell lymphoma is a rare, clinically aggressive lymphoma. Most cases represent a neoplasm of mature non-activated gammadelta T cells. Isochromosome 7q i(7)(q10) is thought to be the primary cytogenetic abnormality of this disease. In this paper, we describe a hepatosplenic gammadelta T-cell lymphoma case, with clonal ring chromosome 7 exemplifying an isochromosome 7q equivalent clonal aberration. A 62-year-old female patient presented with thrombocytopenia, isolated hepatosplenomegaly, and extremely high levels of LDH. Bone marrow work-up demonstrated a sinusoidal cytotoxic T-cell infiltrate with blastic features, while molecular studies verified monoclonal rearrangement for both TCR gamma and TCR delta genes. Cytogenetics revealed clonal abnormalities including ring chromosome 7, trisomy 8, and der(19), while FISH analysis detected 7q amplification with partial deletion of 7p in ring chromosome 7. To the best of our knowledge, this is the first reported T-cell lymphoma case with ring chromosome 7.

Antineoplastic Combined Chemotherapy Protocols↗

Chromosomal evolution of sibling species of the Drosophila willistoni group. I. Chromosomal arm IIR (Muller's element B).

The phylogenetic relationships among nine entities of Drosophila belonging to the D. willistoni subgroup were investigated by establishing the homologous chromosomal segments of IIR chromosome, Muller's element B (equivalent to chromosome 2L of D. melanogaster). The sibling species of the D. willistoni group investigated include D. willistoni, D. tropicalis tropicalis, D. tropicalis cubana, D. equinoxialis, D. insularis and four semispecies of the D. paulistorum complex. The phylogenetic relationships were based on the existence of segments in different triads of species, which could only be produced by overlapping inversions. Polytene banding similarity maps and break points of inversions between species are presented. The implications of the chromosomal data for the phylogeny of the species and comparisons with molecular data are discussed. The aim of this study is to produce phylogenetic trees depicting accurately the sequence of natural events that have occurred in the evolution of these sibling species.

Animals↗

The highly conserved defender against the death 1 (DAD1) gene maps to human chromosome 14q11-q12 and mouse chromosome 14 and has plant and nematode homologs.

We have cloned the cDNA encoding the mouse DAD1 (defender against apoptotic cell death) protein. While showing an expected high homology with the previously cloned human and Xenopus DAD1-encoding cDNAs, this sequence has striking homology to partial cDNA sequences reported from O. sativa (rice) and C. elegans (nematode), suggesting the existence of plant and invertebrate homologs of this highly conserved gene. The human and mouse DAD1 genes map to chromosome 14q11-q12 and chromosome 14, respectively. This mapping data supports and extends the previously reported similarities between human chromosome 14q and mouse chromosome 14.

Amino Acid Sequence↗

Premature chromosome condensation, structural chromosome aberrations, and micronuclei in early mouse embryos after treatment of paternal postmeiotic germ cells with triethylenemelamine: possible mechanisms for chemically induced dominant-lethal mutatiions.

Cytogenetic effects in preimplantation 4-8-cell mouse embryos have been investigated after treating paternal postmeiotic germ cells with triethylenemelamine (TEM). Dose-levels of TEM which do not affect fertilization but yield high incidence of dominant-lethal mutations in sperm and spermatids were shown to produce relatively high frequencies of (a) premature chromosome condensation (PCC), (b) structural chromosome anomalies (breakage-reunion phenomena), and (c) micronuclei in these embryos. The results indicate that genetic death of embryos is mainly due to imbalance (i.e. loss) of genetic material, either from breaks leading to lagging fragments and micronuclei, or from the segregation of various types of exchange figures (dicentrics, rings etc.) resulting in mechanical disturbances of cleavage division. It is suggested that PCC, to some extent, is an expression of TEM-induced long-lived lesions which, transmitted into the egg, prevent the chromosomes in question from replicating and/or condensing normally. This phenomenon could well be associated with loss of chromosome material resulting in embryonic death.

Animals↗

Effects of pingyanymycin on chromosomes: a possible structural basis for chromosome aberration.

Pingyanymycin (PYM), and antitumor-antibiotic complex which belongs to the bleomycin family can induce "G2-free chromatin" and "uncompleted-packing-mitotic figures" (UPM) at increased frequency after treatment of cultured human lymphocytes. PYM can also induce an extraordinarily high frequency of chromosomal breaks but few sister-chromatid exchanges (SCE) in the same experiment, which is similar to the action of bleomycin. To solve this remarkable contradiction we presume that the UPM is related to a basic mechanism for producing chromosomal aberrations. Our results also show that various steps of the chromosomal cycle can be affected by certain chemical agents, and these treatments lead to chromosomal aberrations. Thus, other testing systems should be used in addition to the SCE system.

Bleomycin↗

Chromosome damage and non-disjunction measured at the first cleavage division in normal and chromosomally mutant female mice irradiated at the diakinesis stage of female meiosis.

We have irradiated primary murine oocytes at the diakinesis stage of the first meiotic division with 0.6 Gy X-rays. Fertilized oocytes were cultured overnight to arrest the first cleavage division and display pronuclear chromosomes. All preparations were preferentially stained for centric constitutive heterochromatin and analyzed for structural and numerical radiation effects. Females of 3 different karyotypes were irradiated (all on a Swiss random-bred genetic background): +/+ (221 female pronuclei analyzed), Rb(11.13)4Bnr T(1;13)70H/Rb(1.13)4Bnr T(1;13)70H with 11.13(1) and 1(13) large and small marker bivalents (RbT/RbT, 242 zygotes analyzed) and the same karyotype but with a 1(13)H;1(13) Wa heteromorphic bivalent (RbT/RbT*, 126 zygotes analyzed). Hyperploid chromosome counts were encountered with frequencies of 11.8% (+/+), 11.9% (RbT/RbT) and 16.6% (RbT/RbT*). In this order of karyotypes, the frequencies of dicentrics per zygote were 0.07, 0.16 and 0.11 and the frequencies of fragments 0.13, 0.18 and 0.31. In about half of the supernumerary chromosome spreads, a dicentric chromosome was included. The long marker bivalent 11.13(1) had a non-disjunction frequency of 2.5 times its control value, partially because it was involved in dicentric formation as well. For the RbT/RbT karyotype, the spontaneous maternal non-disjunction level was 5.4%. For the RbT/RbT* karyotype, it can be assumed to be the same or slightly higher because of the 1(13)H;1(13) Wa heteromorphic bivalent. This increased intrinsic sensitivity for non-disjunction was not expressed as an increased sensitivity for aneuploidy after irradiation. This fact and the numerical association between hyperploidy and dicentric formation, both for normal bivalents and for the 11.13(1) marker bivalent, lead us to suppose that in the female mouse, irradiation-caused aneuploidy is effectuated via chromatid exchange. The data presented do not rule out the existence of another mechanism.

Aneuploidy↗

Karyotyping chromosomes by electron microscopy. Condensation-inhibition of G bands in human and Chinese hamster chromosomes by a BrdU-Hoechst 33258 treatment.

A BrdU-Hoechst 33258 treatment of living cells, which selectively induced condensation-inhibition of G-band chromatin in human and Chinese hamster chromosomes, is presented. As a consequence mitotic chromosomes showed high resolution R-banding patterns when examined by light and electron microscopy. Besides each whole chromosome identification, this procedure also permitted the electron microscopic study of specific structures, such as satellites, secondary constrictions, telomeres, centromeres, as well as G and R bands, some of them no visible by light microscopy. We have also observed that the chromatin of G and R bands behave as blocks of chromatin condensation and that G-band chromatin develops condensation along G2. Under the BrdU-Hoechst 33258 treatment, chromatin fibers seem to invert their spontaneous pattern of condensation within the chromosomes.

Animals↗

Retinoblastoma and its association with a deletion in chromosome #13: a survey using high-resolution chromosome techniques.

To our knowledge, 20 cases of retinoblastoma associated with a chromosome #13 aberration have been reported. The present study utilized high-resolution prophase banding analysis of 12 additional retinoblastoma patients to determine the occurrence of chromosome aberrations and identify consistently associated clinical abnormalities. Six male and six female patients were studied representing seven cases of bilateral and five cases of unilateral retinoblastoma. One case of unilateral and two cases of bilateral retinoblastoma and detectable cytogenetic abnormalities, all involving an interstitial deletion of 13q14 on the long arm of one chromosome #13. In all five unilateral cases the tumor manifested in the left orbit, and in all seven bilateral cases the left eye was at a more malignantly advanced stage than the right eye. All three cases with a chromosome abnormality had varying degrees of developmental and/or mental retardation, along with at least one other congenital abnormality. In addition to the 12 cases of retinoblastoma, a patient with severe ophthalmologic abnormalities and mild congenital anomalies was studied by the prophase banding technique and found to be partially trisomic for the 13q14 region with gene loci for optic development and indicate that cytogenetic abnormalities may occur even more frequently in retinoblastoma than indicated by the small number of cases reported in the literature.

Child, Preschool↗

Chromosomes and causation of human cancer and leukemia. XLVII. severe hypodiploidy and chromosome conglomerations in ALL.

A case of acute lymphoblastic leukemia (ALL) of the L1 type with severe hypodiploidy in the marrow cells (modal chromosome number, 36) is described. In addition, most of the metaphases contained chromosome conglomerations which consisted of varying numbers of chromosomes and appeared similar to conglomerations previously observed by us in a case of chronic myelocytic leukemia (CML) in the blastic phase (BP), where some cells contained less than 20 chromosomes. The karyotype of the ALL cells of our case was similar to those of published near-haploid ALL cases, possibly indicative of a common pathway of cytogenetic evolution.

Blood Cell Count↗