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Longmire JL, Brown NC, Meincke LJ, Campbell ML, Albright KL, Fawcett JJ, Campbell EW, Moyzis RK, Hildebrand CE, Evans GA. Construction and characterization of partial digest DNA libraries made from flow-sorted human chromosome 16. Genet Anal Tech Appl 1993; 10:69-76. [PMID: 8110480 DOI: 10.1016/1050-3862(93)90037-j] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In this report, we present the techniques used for the construction of chromosome-specific partial digest libraries from flow-sorted chromosomes and the characterization of two such libraries from human chromosome 16. These libraries were constructed to provide materials for use in the development of a high-resolution physical map of human chromosome 16, and as part of a distributive effort on the National Laboratory Gene Library Project. Libraries with 20-fold coverage were made in Charon-40 (LA16NL03) and in sCos-1 (LA16NC02) after chromosome 16 was sorted from a mouse-human monochromosomal hybrid cell line containing a single homologue of human chromosome 16. Both libraries are approximately 90% enriched for human chromosome 16, have low nonrecombinant backgrounds, and are highly representative for human chromosome-16 sequences. The cosmid library in particular has provided a valuable resource for the isolation of coding sequences, and in the ongoing development of a physical map of human chromosome 16.
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Affiliation(s)
- J L Longmire
- Life Sciences Division and Center for Human Genome Studies, Los Alamos National Laboratory, NM 87545
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2
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Mitchison HM, Williams RE, McKay TR, Callen DF, Thompson AD, Mulley JC, Stallings RL, Hildebrand CE, Moyzis RK, Järvelä I. Refined genetic mapping of juvenile-onset neuronal ceroid-lipofuscinosis on chromosome 16. J Inherit Metab Dis 1993; 16:339-41. [PMID: 8105142 DOI: 10.1007/bf00710278] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- H M Mitchison
- Department of Paediatrics, UCL Medical School, Rayne Institute, London, UK
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Narayanswami S, Doggett NA, Clark LM, Hildebrand CE, Weier HU, Hamkalo BA. Cytological and molecular characterization of centromeres in Mus domesticus and Mus spretus. Mamm Genome 1992; 2:186-94. [PMID: 1543911 DOI: 10.1007/bf00302876] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have applied EM in situ hybridization (EMISH) and pulsed field gel electrophoresis (PFGE) to samples from diploid primary cell cultures and an established cell line to examine in detail the relative organization of the major and minor satellite DNAs and telomere sequences in the genomes of Mus domesticus and Mus spretus. EMISH localizes the Mus domesticus minor satellite to a single site at the centromere-proximal end of each chromosome. Double label hybridizations with both minor satellite and telomere probes show that they are in close proximity and possibly are linked. In fact, PFGE of M. domesticus DNA digested with Sal I and Sfi I reveals the presence of fragments which hybridize to both probes and is consistent with the physical linkage of these two sequences. The M. domesticus minor satellite is the more abundant satellite in Mus spretus. Its distribution in M. spretus is characterized by diffuse labeling with no obvious concentration near chromosome ends. In addition to this repeat the M. spretus genome contains a small amount of DNA that hybridizes to a M. domesticus major satellite probe. Unlike the M. domesticus minor satellite, it is not telomere proximal but is confined to a domain at the border of the centromere and the long arm. Thus, although both species possess all three sequences, except for the telomeres, their distribution relative to one another is not conserved. Based on the results presented, we propose preliminary molecular maps of the centromere regions of Mus domesticus and Mus spretus.
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Affiliation(s)
- S Narayanswami
- Department of Molecular Biology and Biochemistry, University of California, Irvine 92717
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4
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Callen DF, Hildebrand CE, Reeders S. Report of the Second International Workshop on Human Chromosome 16 Mapping. Cytogenet Cell Genet 1992; 60:158-67. [PMID: 1354591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Affiliation(s)
- D F Callen
- Department of Cytogenetics and Molecular Genetics, Adelaide Children's Hospital, Australia
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5
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Abstract
The dinucleotide repetitive sequence, (GT)n, is highly interspersed in eukaryotic genomes and may have functional roles in genetic recombination or the modulation of transcriptional activity. We have examined the distribution and conservation of position of GT repetitive sequences in several mammalian genomes. The distribution of GT repetitive sequences in the human genome was determined by the analysis of over 3700 cosmid clones containing human insert DNA. On average, a GT repetitive sequence occurs every 30 kb in DNA from euchromatic regions. GT repetitive sequences are significantly underrepresented in centric heterochromatin. The density of GT repetitive sequences in the human genome could also be estimated by analyzing GenBank genomic sequences that include introns and flanking sequences. The frequency of GT repetitive sequences found in GenBank human DNA sequences was in close agreement with that obtained by experimental methods. GenBank genomic sequences also revealed that (GT)n repetitive sequences (n greater than 6) occur every 18 and 21 kb, on average, in mouse and rat genomes. Comparative analysis of 31 homologous sequences containing (GT)n repetitive sequences from several mammals representing four orders revealed that the positions of these repeats have been conserved between closely related species, such as humans and other primates. To a lesser extent, positions of GT repetitive sequences have been conserved between species in distantly related groups such as primates and rodents. The distribution and conservation of GT repetitive sequences is discussed with respect to possible functional roles of the repetitive sequence.
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Affiliation(s)
- R L Stallings
- Center for Human Genome Studies, Los Alamos National Laboratory, New Mexico 87545
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6
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Chen LZ, Harris PC, Apostolou S, Baker E, Holman K, Lane SA, Nancarrow JK, Whitmore SA, Stallings RL, Hildebrand CE. A refined physical map of the long arm of human chromosome 16. Genomics 1991; 10:308-12. [PMID: 2071140 DOI: 10.1016/0888-7543(91)90313-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mapping of 33 anonymous DNA probes and 12 genes to the long arm of chromosome 16 was achieved by the use of 14 mouse/human hybrid cell lines and the fragile site FRA16B. Two of the hybrid cell lines contained overlapping interstitial deletions in bands q21 and q22.1. The localization of the 12 genes has been refined. The breakpoints present in the hybrids, in conjunction with the fragile site, can potentially divide the long arm of chromosome 16 into 16 regions. However, this was reduced to 14 regions because in two instances there were no probes or genes that mapped between pairs of breakpoints.
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Affiliation(s)
- L Z Chen
- Department of Cytogenetics and Molecular Genetics, Adelaide Children's Hospital, South Australia
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Affiliation(s)
- D L Grady
- Los Alamos National Laboratory, Genetics Group, NM 87545
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8
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Abstract
The functional human metallothionein (MT) genes are located on chromosome 16q13. We have physically mapped the functional human MT locus by isolation and restriction digest mapping of cloned DNA. The mapped region contains all sequences on chromosome 16 that hybridize to metallothionein gene probes and comprises 14 tightly linked MT genes, 6 of which have not been previously described. This analysis defines the genetic limits of metallothionein functional diversity in the human genome.
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Affiliation(s)
- A K West
- Department of Biochemistry, University of Tasmania, Australia
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Dietz-Band J, Riethman H, Hildebrand CE, Moyzis R. Characterization of polymorphic loci on a telomeric fragment of DNA from the long arm of human chromosome 7. Genomics 1990; 8:168-70. [PMID: 2081591 DOI: 10.1016/0888-7543(90)90240-u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The 240-kb yeast artificial chromosome (YAC) HTY146 (D7S427) containing the telomere from the q arm of human chromosome 7 was subcloned into the cosmid vector sCOS-1. Cosmid subclones were screened for DNA polymorphisms by Southern blot analysis of restriction digests of DNA from random individuals. Four distinct polymorphisms were characterized. These markers provide a resource for defining the end of the genetic map for the long arm of human chromosome 7.
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Affiliation(s)
- J Dietz-Band
- Genetics Group, Los Alamos National Laboratory, New Mexico 87545
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10
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Stallings RL, Torney DC, Hildebrand CE, Longmire JL, Deaven LL, Jett JH, Doggett NA, Moyzis RK. Physical mapping of human chromosomes by repetitive sequence fingerprinting. Proc Natl Acad Sci U S A 1990; 87:6218-22. [PMID: 2385591 PMCID: PMC54504 DOI: 10.1073/pnas.87.16.6218] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We have developed an approach for identifying overlapping cosmid clones by exploiting the high density of repetitive sequences in complex genomes. Individual clones are fingerprinted, using a combination of restriction enzyme digestions followed by hybridization with selected classes of repetitive sequences. This "repeat fingerprinting" technique allows small regions of clone overlap (10-20%) to be unambiguously assigned. We demonstrate the utility of this approach, using the fingerprinting of 3145 cosmid clones (1.25 x coverage), containing one or more (GT)n repeats, from human chromosome 16. A statistical analysis was used to link these clones into 460 contiguous sequences (contigs), averaging 106 kilobases (kb) in length and representing approximately 54% (48.7 Mb) of the euchromatic arms of this chromosome. These values are consistent with theoretical calculations and indicate that 150- to 200-kb contigs can be generated with 1.5 x coverage. This strategy requires the fingerprinting of approximately one-fourth as many cosmids as random strategies requiring 50% minimum overlap for overlap detection. By "nucleating" at specific regions in the human genome, and exploiting the high density of interspersed sequences, this approach allows (i) the rapid generation of large (greater than 100-kb) contigs in the early stages of contig mapping and (ii) the production of a contig map with useful landmarks for rapid integration of the genetic and physical maps.
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Affiliation(s)
- R L Stallings
- Center for Human Genome Studies, Los Alamos National Laboratory, University of California, NM 87545
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11
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Reeders ST, Hildebrand CE, Sutherland GR. Report of the committee on the genetic constitution of chromosome 16. Cytogenet Cell Genet 1990; 55:194-7. [PMID: 2073834 DOI: 10.1159/000133012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Moyzis RK, Albright KL, Bartholdi MF, Cram LS, Deaven LL, Hildebrand CE, Joste NE, Longmire JL, Meyne J, Schwarzacher-Robinson T. Human chromosome-specific repetitive DNA sequences: novel markers for genetic analysis. Chromosoma 1987; 95:375-86. [PMID: 3677921 DOI: 10.1007/bf00333988] [Citation(s) in RCA: 204] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Two recombinant DNA clones that are localized to single human chromosomes were isolated from a human repetitive DNA library. Clone pHuR 98, a variant satellite 3 sequence, specifically hybridizes to chromosome position 9qh. Clone pHuR 195, a variant satellite 2 sequence, specifically hybridizes to chromosome position 16qh. These locations were determined by fluorescent in situ hybridization to metaphase chromosomes, and confirmed by DNA hybridizations to human chromosomes sorted by flow cytometry. Pulsed field gel electrophoresis analysis indicated that both sequences exist in the genome as large DNA blocks. In situ hybridization to intact interphase nuclei showed a well-defined, localized organization for both DNA sequences. The ability to tag specific human autosomal chromosomes, both at metaphase and in interphase nuclei, allows novel molecular cytogenetic analyses in numerous basic research and clinical studies.
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Affiliation(s)
- R K Moyzis
- Genetics Group, Los Alamos National Laboratory, University of California, NM 87545
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Longmire JL, Albright KL, Lewis AK, Meincke LJ, Hildebrand CE. A rapid and simple method for the isolation of high molecular weight cellular and chromosome-specific DNA in solution without the use of organic solvents. Nucleic Acids Res 1987; 15:859. [PMID: 3822818 PMCID: PMC340478 DOI: 10.1093/nar/15.2.859] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Abstract
Heavy metal induction of the synthesis of metallothioneins (MTs) provides an ideal model system for basic mechanistic studies of gene expression. Cell lines varying in their resistance to heavy metals have been isolated through a regime of exposure to serially increasing levels of Cd followed by clonal isolation. These cell lines have been used to examine the role of methylation and amplification in the Cd-resistant (Cdr) phenotype. It is suggested that regulation of expression of the MT genes in Cdr Chinese hamster cells is modulated at both the transcriptional and translational levels. An analysis of the MT2 gene sequence has uncovered a potential alternative splice site in the first intron. Usage of this site would insert 3 or 12 additional amino acids between amino acids 9 and 10. Analysis of the splicing pattern of the MT2 gene transcript in cultured cells has indicated that the second intron is preferentially removed prior to first intron excision.
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Affiliation(s)
- D L Grady
- Genetics Group, Los Alamos National Laboratory, NM 87545
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16
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Stallings RL, Crawford BD, Tobey RA, Tesmer J, Hildebrand CE. 5-Azacytidine-induced conversion to cadmium resistance correlates with early S phase replication of inactive metallothionein genes in synchronized CHO cells. Somat Cell Mol Genet 1986; 12:423-32. [PMID: 2429375 DOI: 10.1007/bf01539913] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previous studies have shown both hypermethylation and late replication of DNA sequences to be associated with gene inactivity. To determine whether there is a causal relationship between patterns of DNA methylation and replication timing during S phase, we have examined the timing of replication of the inactive, hypermethylated metallothionein (MT) I and II genes in synchronized, cadmium-sensitive (Cds) CHO cells. The time of S-phase replication of the MT genes was ascertained by determining the period of S phase wherein cadmium-resistant (Cdr) cells could be induced with highest frequency by pulse treatment of synchronized Cds cells with the hypomethylating drug 5-azacytidine (5-aza-CR), and by analyzing Southern blots of density fractionated DNAs isolated from synchronized cells pulse-labeled with BrdU during different intervals after release from hydroxyurea blockade. Southern filter hybridization analyses demonstrated replication of both MTI and II gene sequences within the first half of S phase. Consistent with this result, phenotypic conversion of Cds to Cdr was maximal immediately after hydroxyurea release and decreased abruptly within three hours. The replication of inactive hypermethylated MT genes in early S phase argues that transcriptional inactivity and gene-specific hypermethylation are not sufficient conditions for late DNA replication.
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Van Dilla MA, Deaven LL, Albright KL, Allen NA, Aubuchon MR, Bartholdi MF, Brown NC, Campbell EW, Carrano AV, Clark LM, Cram LS, Crawford BD, Fuscoe JC, Gray JW, Hildebrand CE, Jackson PJ, Jett JH, Longmire JL, Lozes CR, Luedemann ML, Martin JC, McNinch JS, Meincke LJ, Mendelsohn ML, Meyne J, Moyzis RK, Munk AC, Perlman J, Peters DC, Silva AJ, Trask BJ. Human Chromosome–Specific DNA Libraries: Construction and Availability. Nat Biotechnol 1986. [DOI: 10.1038/nbt0686-537] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Preston RA, Hildebrand CE, Purcell GH, Ellis J, Stelzried CT, Finley SG, Sagdeev RZ, Linkin VM, Kerzhanovich VV, Altunin VI, Kogan LR, Kostenko VI, Matveenko LI, Pogrebenko SV, Strukov IA, Akim EL, Alexandrov YN, Armand NA, Bakitko RN, Vyshlov AS, Bogomolov AF, Gorchankov YN, Selivanov AS, Ivanov NM, Tichonov VF, Blamont JE, Boloh L, Laurans G, Boischot A, Biraud F, Ortega-Molina A, Rosolen C, Petit G. Determination of Venus Winds by Ground-Based Radio Tracking of the VEGA Balloons. Science 1986; 231:1414-6. [PMID: 17748082 DOI: 10.1126/science.231.4744.1414] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A global array of 20 radio observatories was used to measure the three-dimensional position and velocity of the two meteorological balloons that were injected into the equatorial region of the Venus atmosphere near Venus midnight by the VEGA spacecraft on 11 and 15 June 1985. Initial analysis of only radial velocities indicates that each balloon was blown westward about 11,500 kilometers (8,000 kilometers on the night side) by zonal winds with a mean speed of about 70 meters per second. Excursions of the data from a model of constant zonal velocity were generally less than 3 meters per second; however, a much larger variation was evident near the end of the flight of the second balloon. Consistent systematic trends in the residuals for both balloons indicate the possibility of a solar-fixed atmospheric feature. Rapid variations in balloon velocity were often detected within a single transmission (330 seconds); however, they may represent not only atmospheric motions but also self-induced aerodynamic motions of the balloon.
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Sagdeev RZ, Linkin VM, Kerzhanovich VV, Lipatov AN, Shurupov AA, Blamont JE, Crisp D, Ingersoll AP, Elson LS, Preston RA, Hildebrand CE, Ragent B, Seiff A, Young RE, Petit G, Boloh L, Alexandrov YN, Armand NA, Bakitko RV, Selivanov AS. Overview of VEGA Venus Balloon in Situ Meteorological Measurements. Science 1986; 231:1411-4. [PMID: 17748081 DOI: 10.1126/science.231.4744.1411] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The VEGA balloons made in situ measurements of pressure, temperature, vertical wind velocity, ambient light, frequency of lightning, and cloud particle backscatter. Both balloons encountered highly variable atmospheric conditions, with periods of intense vertical winds occurring sporadically throughout their flights. Downward winds as large as 3.5 meters per second occasionally forced the balloons to descend as much as 2.5 kilometers below their equilibrium float altitudes. Large variations, in pressure, temperature, ambient light level, and cloud particle backscatter (VEGA-1 only) correlated well during these excursions, indicating that these properties were strong functions of altitude in those parts of the middle cloud layer sampled by the balloons.
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Deaven LL, Van Dilla MA, Bartholdi MF, Carrano AV, Cram LS, Fuscoe JC, Gray JW, Hildebrand CE, Moyzis RK, Perlman J. Construction of human chromosome-specific DNA libraries from flow-sorted chromosomes. Cold Spring Harb Symp Quant Biol 1986; 51 Pt 1:159-67. [PMID: 3472712 DOI: 10.1101/sqb.1986.051.01.019] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Hildebrand CE, Gonzalez FJ, Kozak CA, Nebert DW. Regional linkage analysis of the dioxin-inducible P-450 gene family on mouse chromosome 9. Biochem Biophys Res Commun 1985; 130:396-406. [PMID: 4040754 DOI: 10.1016/0006-291x(85)90430-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The dioxin-inducible P-450 gene family in the C57BL/6N mouse comprises two genes, P1-450 and P3-450. Restriction endonuclease-digested genomic DNA was probed with P1-450 and P3-450 full-length cDNA clones in an attempt to find species-specific fragment length differences between mouse and hamster cell lines and any restriction fragment length polymorphism among four inbred mouse strains. With this Southern blot hybridization technique, PstI fragments were used to distinguish between the mouse and hamster P1-450/P3-450 genes, and PvuII fragments were used to distinguish P3-450 differences between the AKR/J and C57L/J inbred strains. Analysis of nineteen mouse X hamster somatic cell hybrid lines and sixteen AKXL (AKR/J X C57L/J) recombinant inbred lines showed that the P1-450/P3-450 genes are located near the Mpi-1 locus, between the Thy-1 and Pk-3 loci, in the middle portion of mouse chromosome 9.
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Hildebrand CE, Stallings RL, Gonzalez FJ, Nebert DW. Assignment of dioxin-inducible cytochrome P-450 gene family to Chinese hamster chromosome 4. Somat Cell Mol Genet 1985; 11:391-5. [PMID: 3860967 DOI: 10.1007/bf01534416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The 2,3,7,8-tetrachlorodibenzo-p-dioxin-inducible cytochrome P-450 gene family (P1-450 and P3-450 in the C57BL/6N mouse) has recently been localized to mouse chromosome 9. In the present study, HindIII-digested DNA from Chinese hamster, mouse, and 20 Chinese hamster X mouse somatic cell hybrids and subclones segregating hamster chromosomes was probed with the mouse P1-450 and P3-450 full-length cDNA clones. Hamster P-450 gene fragments (6.0 and 7.4 kb) were assigned to Chinese hamster chromosome 4. These data are consistent with linkage conservation among these two P-450 sequences and four other loci on mouse chromosome 9 that map to hamster chromosome 4.
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Hildebrand CE, Gonzalez FJ, McBride OW, Nebert DW. Assignment of the human 2,3,7,8-tetrachlorodibenzo-p-dioxin-inducible cytochrome P1-450 gene to chromosome 15. Nucleic Acids Res 1985; 13:2009-16. [PMID: 4000952 PMCID: PMC341131 DOI: 10.1093/nar/13.6.2009] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The human 2,3,7,8-tetrachlorodibenzo-p-dioxin-inducible cytochrome P1-450 full-length cDNA has been recently isolated and sequenced [Jaiswal, A.K., Gonzalez, F.J. and Nebert, D.W. (1985) Science, in press]. A 1521-bp 5' DNA fragment representing almost all of the translating region was used to probe DNA from human, mouse, hamster, 53 human X mouse somatic cell hybrids, and 36 human X hamster somatic cell hybrids. These data indicate that the P1-450 gene resides on human chromosome 15. Knowledge of the chromosomal assignment of this gene should help in our understanding of its regulation and role in development and disease.
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Stallings RL, Munk AC, Longmire JL, Hildebrand CE, Crawford BD. Assignment of genes encoding metallothioneins I and II to Chinese hamster chromosome 3: evidence for the role of chromosome rearrangement in gene amplification. Mol Cell Biol 1984; 4:2932-6. [PMID: 6527691 PMCID: PMC369309 DOI: 10.1128/mcb.4.12.2932-2936.1984] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cadmium resistant (Cdr) variants with coordinately amplified metallothionein I and II (MTI and MTII) genes have been derived from both Chinese hamster ovary and near-euploid Chinese hamster cell lines. Cytogenetic analyses of Cdr variants consistently revealed breakage and rearrangement involving chromosome 3p. In situ hybridization with a Chinese hamster MT-encoding cDNA probe localized amplified MT gene sequences near the translocation breakpoint involving chromosome 3p. These observations suggested that both functionally related, isometallothionein loci are linked on Chinese hamster chromosome 3. Southern blot analyses of DNAs isolated from a panel of Chinese hamster X mouse somatic cell hybrids which segregate hamster chromosomes confirmed that both MTI and MTII are located on chromosome 3. We speculate that rearrangement of chromosome 3p could be causally involved with the amplification of MT genes in Cdr hamster cell lines.
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Seagrave J, Hildebrand CE, Enger MD. Effects of cadmium on glutathione metabolism in cadmium sensitive and cadmium resistant Chinese hamster cell lines. Toxicology 1983; 29:101-7. [PMID: 6658793 DOI: 10.1016/0300-483x(83)90042-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Three cadmium resistant sublines, Cdr20F4, Cdr30F9, and Cdr200T1, resistant to 26, 40, and 145 micron CdCl2, respectively, have been derived from the cadmium sensitive Chinese hamster cell line CHO (resistant to 0.2 microM CdCl2). The resistance appears to be largely a function of the increased ability of the variant cells to induce the synthesis of metallothioneins (MTs) in response to cadmium, as the incorporation of [35S]cysteine into MTs ranges from an undetectable level to nearly 60% of the total cysteine incorporation into proteins in the CHO and Cdr200T1 cell lines, respectively. Treatment of the cadmium resistant sublines and the parent line with maximal subtoxic levels of Cdcl2 produced increases in the concentration of glutathione and glutathione S-transferase activity. In the parent, cadmium-sensitive CHO cell, the glutathione concentration began to increase after 9 h of exposure to 0.22 microM CdCl2 to over 250% of control level by 12 h. In 1 cadmium resistant line (Cdr20F4) the increase, again at 9 h, was preceded by a decrease, possibly due to depletion of the cysteine pools by the cadmium-induced MT synthesis. The second cadmium-resistant cell line (Cdr30F9) displayed no decrease, and the most cadmium-resistant line (Cdr200T1) showed the decrease and a recovery, but no significant increase by 12 h. In all cell lines there was a small but significant increase in glutathione S-transferase activity by 9 or 12 h. These responses may be specific for the thiol-reactive metal, cadmium, or may represent more general responses to cellular toxicity.
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Tobey RA, Seagrave J, Hildebrand CE. Induced resistance to alkylating agent toxicity obtainable by pretreatment with combinations of trace elements. Biol Trace Elem Res 1983; 5:423-31. [PMID: 24263664 DOI: 10.1007/bf02988936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/1983] [Accepted: 04/02/1983] [Indexed: 10/21/2022]
Abstract
Survival (monitored as colony-forming ability) of Chinese hamster Cd(r) 20F4 cells following exposure to the alkylating agent melphalan was enhanced by pretreating cells with combinations of the trace elements zinc, selenium, and copper. Cultures simultaneously pretreated with any two trace elements prior to exposure to melphalan exhibited survival values that were either equivalent to (Zn + Cu or Zn + Se) or somewhat greater than (Se + Cu) the sum of survivals obtained in cultures pretreated with singly administered elements. Simultaneous pretreatment with all three trace element inducers produced dramatic increases in survival level upon subsequent challenge with melphalan that ranged from 20-to 130-fold over the levels achieved in non-induced cultures.
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Affiliation(s)
- R A Tobey
- Toxicology Group, MS M880, Los Alamos National Laboratory, 87545, Los Alamos, New Mexico
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Seagrave J, Tobey RA, Hildebrand CE. Zinc effects on glutathione metabolism relationship to zinc-induced protection from alkylating agents. Biochem Pharmacol 1983; 32:3017-21. [PMID: 6639670 DOI: 10.1016/0006-2952(83)90243-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Several aspects of the effects of zinc on the metabolism of glutathione were examined in the Chinese hamster cell (line CHO) and in three derived sublines which differ in their resistance to the thiol reactive heavy metal cadmium. In the parental CHO cell, which does not induce the synthesis of metallothionein in response to zinc, glutathione levels remained approximately constant during the first 6 hr of zinc exposure. In the resistant cell lines, which induce the synthesis of metallothionein in response to zinc, the glutathione levels dropped transiently during zinc exposure. In all cell lines except the most cadmium resistant line, the glutathione levels after 12 hr were increased up to 3-fold relative to pretreatment levels. Similarly, the glutathione S-transferase activity measured by the conjugation of 1-chloro-2,4-dinitrobenzene to glutathione was increased after 9-12 hr of zinc treatment in all except the most highly cadmium resistant cell line. Glutathione reductase was not affected consistently by zinc treatment; however, the level of activity of this enzyme in the most highly cadmium resistant line was two to three times greater than that observed in the other cell lines. These effects are considered in relation to the zinc-induced protection of these cells from the toxic effect of the alkylating agent melphalan.
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Abstract
Cd2+ cytotoxicity, uptake, and partitioning, and Cd2+-induced metallothioneine synthesis were studied in cultured peripheral human blood cells. Mononuclear cells were found to resist relatively high levels of Cd2+. Few cells were killed below 50 microM Cd2+. Above this value, survival decreased exponentially with dose. The mean LD50 for mononuclear cells cultured in Cd2+ for 40 hr was 100 microM. Polymorphonuclear cells (granulocytes) were found to be more resistant, with a significantly higher threshold and LD50, and a more complex dose response. Most of the Cd2+ incorporated by blood cells was taken up by nucleated cells. Despite their greater resistance, polymorphonuclear cells incorporated more Cd2+ at higher doses (50 to 150 microM) than did mononuclear cells. No Cd2+ was bound to metallothioneine in polymorphonuclear cells following exposure to Cd2+ for even extended periods of time (18 hr) at high doses of 109Cd2+ (25 microM). Instead Cd2+ appeared in a Sephadex G-75 peak of approximately 60,000 Da, as well as in the void peak. No significant amount of preexisting metallothioneine (MT) or metallothioneine mRNA was found in the mononuclear cells. However, MT synthesis was induced rapidly following exposure to Cd2+. [109Cd2+]MT appeared within 1 hr following exposure to 50 microM 109Cd2+, and MT synthesis rates measured from [35S]cysteine incorporation were found to be maximal within 4 hr.
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Griffith BB, Walters RA, Enger MD, Hildebrand CE, Griffith JK. cDNA cloning and nucleotide sequence comparison of Chinese hamster metallothionein I and II mRNAs. Nucleic Acids Res 1983; 11:901-10. [PMID: 6687636 PMCID: PMC325761 DOI: 10.1093/nar/11.3.901] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Polyadenylated RNA was extracted from a cadmium resistant Chinese hamster (CHO) cell line, enriched for metal-induced, abundant RNA sequences and cloned as double-stranded cDNA in the plasmid pBR322. Two cDNA clones, pCHMT1 and pCHMT2, encoding two Chinese hamster isometallothioneins were identified, and the nucleotide sequence of each insert was determined. The two Chinese hamster metallothioneins show nucleotide sequence homologies of 80% in the protein coding region and approximately 35% in both the 5' and 3' untranslated regions. Interestingly, an 8 nucleotide sequence (TGTAAATA) has been conserved in sequence and position in the 3' untranslated regions of each metallothionein mRNA sequenced thus far. Estimated nucleotide substitution rates derived from interspecies comparisons were used to calculate a metallothionein gene duplication time of 45 to 120 million years ago.
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Abstract
A number of toxic chemical and physical agents elicit the induction of a series of protein species, some of which react with the agents and render them nontoxic. A few of the induced species (such as metallothionein) are rich in thiol groups that might be expected to react with alkylating agents and render them nontoxic. If a safe means could be found for selectively enhancing the synthesis of alkylating-agent-reactive species in normal but not tumor cells, such a procedure would have ramifications in the area of cancer chemotherapy. In this report, we have utilized a variety of trace elements (Zn, Se, Cu, As) as inducers of synthesis of protective species in line CHO Chinese hamster cells and in a number of derived variants to determine whether this type of approach can be utilized to increase resistance to alkylating-agent toxicity. Our results indicate that Zn, Se and Cu elicit a protective response (increased survival, monitored by colony-forming ability) against the toxic effects of iodoacetate or melphalan, and, at least in the case of zinc, at levels that are physiologically reasonable. Arsenite appears to be a marginally effective inducer in the CHO cell and an ineffective inducer in the Cdr20F4 variant cell. The increased survival is not attributable to metallothionein inducibility, decreased availability of the alkylating agent in the medium, or decreased uptake of the drug into the trace-element-pretreated cells. The protective responses induced by zinc or selenite alone are additive in cells receiving both trace elements prior to exposure to alkylating agent, which suggests that different domains of response are elicited by the two metals. In view of reported differences in inducibility of protective proteins between normal and tumor cells, a possibility is raised for a novel approach to alkylating-agent chemotherapy that is somewhat analogous to the protocol utilized in high-dose methotrexate therapy.
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Hildebrand CE, Strniste GF. Ultraviolet light inactivation of zinc-mediated metallothionein induction in normal and repair-deficient human cells. Mutat Res 1982; 95:417-26. [PMID: 7121493 DOI: 10.1016/0027-5107(82)90275-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Synthesis of the low molecular weight, thiol-rich, metal-binding metallothioneins (MTS) is undetectable in normal human (NF) or xeroderma pigmentosum (XP) fibroblasts grown in the absence of excess ZnCl2. Addition of 200 microM ZnCl2 to the growth medium produces an increased MT synthesis rising from the basal rate to a rate at least 50-fold greater than basal rate within 7 h. MT induction kinetics in confluent and in exponentially growing subconfluent monolayers were indistinguishable. Zn2+-mediated MT induction is sensitive to actinomycin D suggesting that the induction process is under transcriptional control. Ultraviolet light irradiation causes a dose-dependent inactivation of Zn2+-mediated MT induction in both NF and XP cells. Post-irradiation incubation of UV-irradiated cells using liquid holding techniques leads to reactivation of Zn2+-mediated MT induction in NF cells but not in XP cells. These findings suggest the utility of MT induction produce transcription-terminating lesions, and (b) in evaluating cellular repair capacity for this class of DNA lesions.
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Tobey RA, Enger MD, Griffith JK, Hildebrand CE. Zinc-induced resistance to alkylating agent toxicity. Cancer Res 1982; 42:2980-4. [PMID: 7093947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Suspension cultures of Chinese hamster ovary cells and three derived cadmium-resistant variants were exposed to 100 microM ZnCl2 prior to treatment with the alkylating agent, melphalan, and cytotoxicity was then determined by measuring colony-forming ability. A 10-fold or greater enhancement in survival of all zinc-pretreated cultures subsequently exposed to melphalan was observed which was unrelated to metallothionein induction capacity. Although the maximum achievable protection afforded by zinc occurred in cultures receiving 100 microM ZnCl2, concentrations of zinc only slightly in excess of levels found in human serum were shown to provide a 4.5-fold enhancement of protection, indicating that the phenomenon can also be induced at physiologically reasonable levels. These results suggest the existence of a novel zinc-inducible mechanism which protects cells against the toxic effects of alkylating agents.
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Griffith JK, Buckingham JM, Hanners JL, Hildebrand CE, Walters RA. Plasmid-conferred tetracycline resistance confers collateral cadmium sensitivity of E. coli cells. Plasmid 1982; 8:86-8. [PMID: 6755512 DOI: 10.1016/0147-619x(82)90044-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Tobey RA, Enger MD, Griffith JK, Hildebrand CE. Zinc-induced resistance to alklylating agents: lack of correlation between cell survival and metallothionein content. Toxicol Appl Pharmacol 1982; 64:72-8. [PMID: 7112586 DOI: 10.1016/0041-008x(82)90323-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Hildebrand CE, Strniste GF. Differential reactivation of zinc-mediated metallothionein induction in ultraviolet-irradiated normal and repair-deficient human cells. J Cell Biochem 1982; 18:121-33. [PMID: 7068776 DOI: 10.1002/jcb.1982.240180110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The ubiquitous, low-molecular-weight, thiol-rich, metal-binding protein, metallothionein (MT), can be induced in cultured normal human fibroblasts (NF) and xeroderma pigmentosum (XP) cells by exposure to ZnCl2. Both NF and XP cells tolerate up to 200 microM ZnCl2 in the growth medium, upon addition of ZnCl2 (200 microM) to monolayer cultures, both NF and XP cells showed similar kinetics for the induction of MT synthesis: Within 7 hours the MT synthesis rate rose from a low, marginally detectable rate to a maximal rate at least 50-fold greater than the basal rate. The induction of MT synthesis in both cell types was inhibited by actinomycin D (5 microgram/ml), indicating that the induction process is controlled at the level of transcription. Exposure of NF and XP cells to far ultraviolet light (UV) followed by induction with ZnCl2 resulted in a UV dose-dependent decrease in the he maximal rate of MT synthesis measured 8.5 hours postirradiation. The UV sensitivity of the MT induction was greater in XP cells than in NF cells. However, considerations of the differential repair capacities of NF and XP cells superimposed upon the kinetics of MT induction were invoked to explain the apparent differential UV sensitivity of MT induction. Liquid holding recovery experiments showed that NF cells possess the capacity to reactivate this inducible gene function rapidly while XP cells are deficient in the reactivation capacity. These results are discussed in the context of both UV transcriptional mapping of this inducible gene function and development of techniques for measuring repair of transcription-blocking lesions.
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Griffith JK, Enger MD, Hildebrand CE, Walters RA. Differential induction by cadmium of a low-complexity ribonucleic acid class in cadmium-resistant and cadmium-sensitive mammalian cells. Biochemistry 1981; 20:4755-61. [PMID: 6170314 DOI: 10.1021/bi00519a035] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The Chinese hamster ovary (CHO) cell line and the subline Cdr20F4 have been used to compare cadmium-induced ribonucleic acid (RNA) synthesis in cadmium-sensitive and cadmium-resistant cells, respectively. Gel electrophoresis of the cell-free translation products directed by polyadenylated [poly(A+)] messenger RNA (mRNA) from cadmium-induced Cdr20F4 cells revealed four low molecular weight species (Mr 7000-21 000), including metallothionein, whose synthesis was not detected after translation of either cadmium-induced or uninduced CHO cell poly(A+) mRNA. At least two of these species were also detected after translation of an abundant 400-nucleotide (NT) RNA class purified from the cadmium-induced Cdr20F4 cell RNA. Molecular hybridization of complementary deoxyribonucleic acid (cDNA) complementary to this abundant, cadmium-induced 400-NT RNA fraction indicates that the cadmium-induced RNA class possesses a total kinetic complexity of about 2000 NT's. At least half of these inducible sequences are also represented constitutively in less abundant RNA classes of both uninduced CHO and Cdr20F4 cells. Induction of Cdr20F4 cells with cadmium increases the cellular concentration of the 2000-NT-complexity RNA class to a level at least 2 x 10(3)-fold greater than its constitutive level in uninduced Cdr20F4 cells. Induction of CHO cells with cadmium increases the cellular concentration of a subset of the sequences in the 2000-NT-complexity class, but only to a level 100-fold over the constitutive level in uninduced CHO cells. The remainder of these sequences belongs to the least abundant CHO cell poly(A+) RNA class.
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Enger MD, Ferzoco LT, Tobey RA, Hildebrand CE. Cadmium resistance correlated with cadmium uptake and thionein binding in CHO cell variants Cdr20f4 and Cdr30f9. J Toxicol Environ Health 1981; 7:675-90. [PMID: 7265303 DOI: 10.1080/15287398109530011] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Hildebrand CE, Enger MD. Regulation of Cd2+/Zn2+-stimulated metallothionein synthesis during induction, deinduction, and superinduction. Biochemistry 1980; 19:5850-7. [PMID: 7459344 DOI: 10.1021/bi00566a029] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Hildebrand CE, Enger MD, Tobey RA. Comparative studies of zinc metabolism in cultured chinese hamster cells with differing metallothionein-induction capacities. Biol Trace Elem Res 1980; 2:235-46. [PMID: 24271403 DOI: 10.1007/bf02783822] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/1980] [Accepted: 05/05/1980] [Indexed: 11/29/2022]
Abstract
Previous work in our laboratory led to the isolation of a cadmium (Cd)-resistant variant (Cd(r)2C10) of the line CHO Chinese Hamster cell having a 10-fold greater resistance to the cytotoxic action of Cd(2+) compared with the CHO cell. This resistance was attributed to an increased capacity of the Cd(2+)-resistant Cd(r)2C10 subline to induce synthesis of the Cd(2+)- and Zn(2+)-binding protein(s), metallothionein(s) (MT). Evidence that Cd(2+) behaves as an analog of the essential trace metal, Zn(2+), especially as an inducer of MT synthesis, suggested that the Cd(r) and CHO cell types could be employed to investigate cellular Zn(2+) metabolism. In the present study, measurements were made to compare CHO and Cd(r) cell types for (a) growth as a function of the level of ZnCl2 added to the culture medium, (b) uptake and subcellular distribution of Zn(2+), and (c) capacity to induce MT synthesis. The results of these measurements indicated that (a) both CHO and Cd(r) cell types grew normally (T d≊16-18 h) during exposures to Zn(2+) at levels up to 100 μM added to the growth medium, but displayed abrupt growth inhibition at higher Zn(2+) levels, (b) Cd(r) cells incorporate fourfold more Zn(2+) during a 24-h exposure to the maximal subtoxic level of Zn(2+) and (c) the CHO cell lacks the capacity to induce MT synethesis while the Cd(r) cell is proficient in this response during exposure to the maximal subtoxic Zn(2+) level. These findings suggest that (a) the CHO and Cd(r) cell systems will be useful in further studies of cellular Zn(2+) metabolism, especially in comparisons of Zn(2+) metabolism in the presence and absence of induction of the Zn(2+)-sequestering MT and (b) a relationship exists between cellular capacity to induce MT synthesis and capacity for cellular Zn(2+) uptake.
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Affiliation(s)
- C E Hildebrand
- Genetics and Toxicology Groups, Life Sciences Division, University of California, Los Alamos Scientific Laboratory, 87545, Los Alamos, New Mexico
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Enger MD, Rall LB, Walters RA, Hildebrand CE. Regulation of induced thionein gene expression in cultured mammalian cells: effects of protein synthesis inhibition of translatable thionein mRNA levels in regulatory variants of the CHO cell. Biochem Biophys Res Commun 1980; 93:343-8. [PMID: 7387648 DOI: 10.1016/0006-291x(80)91082-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Hildebrand CE, Tobey RA, Campbell EW, Enger MD. A cadmium-resistant variant of the Chinese hamster (CHO) cell with increased metallothionein induction capacity. Exp Cell Res 1979; 124:237-46. [PMID: 510415 DOI: 10.1016/0014-4827(79)90199-x] [Citation(s) in RCA: 112] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Enger MD, Rall LB, Hildebrand CE. Thionein gene expression in Cd++-variants of the CHO cell: correlation of thionein synthesis rates with translatable mRNA levels during induction, deinduction, and superinduction. Nucleic Acids Res 1979; 7:271-88. [PMID: 493142 PMCID: PMC328012 DOI: 10.1093/nar/7.1.271] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The relationship of thionein synthesis rates to translatable cytoplasmic thionein mRNA levels was investigated for the first time in a cultured cell system. Thionein synthesis was induced in Cdr, a cadmium-resistant variant of CHO, by exposure to 2 microM CdCl2. Following a short (1.5 hr) lag, thionein synthesis increases to a rate that is at least 30 times the uninduced rate 7-8 hr after addition of Cd++. This increase is blocked by the coincident addition of a actinomycin D. Cytoplasmic thionein mRNA levels, measured by translation in a modified wheat germ system, increase rapidly following induction to values approximately 25 times uninduced levels within 6-8 hr. The increase in thionein mRNA precede proportionate increases in thionein synthesis by 0.5-1.0 hr. Continued exposure to Cd++ results in a decreased thionein synthesis rate after 8 hr. By 30 hr, the rate is one-half that seen 6-8 hr after induction. Removal of Cd++ after 8 hr results in a rapid decrease in thionein synthesis (t 1/2 approximately 4 hr). Both decreases are inhibited by the addition of actinomycin. In all instances--induction, deinduction, and actinomycin-mediated "super-induction"--translatable thionein mRNA levels and thionein synthesis rates increase, decrease, or are maintained coordinately. The results suggest that thionein synthesis in Cdr is controlled primarily by the level of translatable cytoplasmic thionein mRNA.
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Hildebrand CE, Cram LS. Distribution of cadmium in human blood cultured in low levels of CdCl2: accumulation of Cd in lymphocytes and preferential binding to metallothionein. Proc Soc Exp Biol Med 1979; 161:438-43. [PMID: 482273 DOI: 10.3181/00379727-161-40569] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Enger MD, Campbell EW, Ratliff RL, Tobey RA, Hildebrand CE, Kissane RJ. Cadmium-induced alterations in RNA metabolism in cultures of Chinese hamster cells sensitive to and resistant to the cytotoxic effects of cadmium. J Toxicol Environ Health 1979; 5:711-28. [PMID: 490682 DOI: 10.1080/15287397909529782] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A variant population (CdR) of cultured Chinese hamster cells (line CHO) was derived that is more than 100 times as resistant to the cytotoxic effects of Cd2+ than is the parent population. The effects on RNA metabolism of exposure to sublethal concentrations of Cd2+ were studied in CHO and CdR. Exposure to 2 X 10(-7) M CdCl2 for 24 h resulted in increased polysome content (1.2 times) and increased uridine or adenosine incorporation into heterogeneous nuclear RNA (1.2-1.4 times) and messenger RNA ((1.5-1.7 times) in both populations. Measurement of ATP pool specific activity following exposure to radiolabeled adenosine showed that increased incorporation reflects increased synthesis. The equivalence of CHO and CdR in dose-response in terms of stimulated RNA synthesis and their disparity in dose-response in terms of cytotoxic effects indicate that the systems involved in conferring protection against the lethal effects of Cd2+ are not similarly involved in attenuating the effects on RNA metabolism.
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Hildebrand CE, Tobey RA, Gurley LR, Walters RA. Action of heparin on mammalian nuclei. II. Cell-cycle-specific changes in chromatin organization correlate temporally with histone H1 phosphorylation. Biochim Biophys Acta 1978; 517:486-99. [PMID: 626747 DOI: 10.1016/0005-2787(78)90215-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The interaction of the polyanion heparin with the inner histones of chromatin has been used to detect changes in chromatin organization associated with cell-cycle traverse. Synchronized populations of Chinese hamster cells were obtained either in early G1 or near the G1/S boundary. The rate of interaction of heparin with chromatin-associated inner histones was measured using nuclei isolated from synchronized cell populations in different phases of the cell cycle. A G1-specific decrease in rate of interaction of heparin with inner histones was observed and found to be independent of the presence of hydroxyurea during traverse of G1. A further decrease in heparin-inner histone interaction occurred in late S and G2. These changes correlate temporally with the interphase phosphorylation(s) of histone H1. This correlation is discussed within the framework of current models of higher order chromatin structure (i.e. organization above the nucleosome level). Analysis of the cooperativity of interaction of heparin with inner histones was performed using the kinetic analog of the Hill equation. This analysis suggests that the organization of inner histones on chromatin does not undergo large variations during the cell cycle.
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Tolson RH, Duxbury TC, Born GH, Christensen EJ, Diehl RE, Farless D, Hildebrand CE, Mitchell RT, Molko PM, Morabito LA, Palluconi FD, Reichert RJ, Taraji H, Veverka J, Neugebauer G, Findlay JT. Viking First Encounter of Phobos: Preliminary Results. Science 1978; 199:61-4. [PMID: 17841954 DOI: 10.1126/science.199.4324.61] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
During the last 2 weeks of February 1977, an intensive scientific investigation of the martian satellite Phobos was conducted by the Viking Orbiter-1 (VO-1) spacecraft. More than 125 television pictures were obtained during this period and infrared observations were made. About 80 percent of the illuminated hemisphere was imaged at a resolution of about 30 meters. Higher resolution images of limited areas were also obtained. Flyby distances within 80 kilometers of the surface were achieved. An estimate of the mass of Phobos (GM) was obtained by observing the effect of Phobos's gravity on the orbit of VO-1 as sensed by Earth-based radiometric tracking. Preliminary results indicate a value of GM of 0.00066 +/- 0.00012 cubic kilometer per second squared (standard deviation of 3) and a mean density of about 1.9 +/- 0.6 gram per cubic centimeter (standard deviation of 3). This low density, together with the low albedo and the recently determined spectral reflectance, suggest that Phobos is compositionally similar to type I carbonaceous chondrites. Thus, either this object formed in the outer part of the asteroid belt or Lewis's theory that such material cannot condense at 1.5 astronomical units is incorrect. The data on Phobos obtained during this first encounter period are comparable in quantity to all of the data on Mars returned by Mariner flights 4, 6, and 7.
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Hildebrand CE, Gurley LR, Tobey RA, Walters RA. Action of heparin on mammalian nuclei. I. Differential extraction of histone H1 and cooperative removal of histones from chromatin. Biochim Biophys Acta 1977; 477:295-311. [PMID: 884118 DOI: 10.1016/0005-2787(77)90054-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Heparin interacts strongly with the histone component of chromatin, forming heparin-histone complexes which resist dissociation by 0.2 M H2SO4. Heparin treatment of unfractionated histones isolated from nuclei of Chinese hamster cells indicates that the affinities of the histone classes for heparin appear in the order from greatest to least: (H3, H4) greater than (H2A, H2B) greater than H1. However, when isolated nuclei are treated with heparin, H1 is released from the chromatin more readily than the other four histone classes. The release of these four histones (H2A, H2B, H3, and H4) is coordinate and occurs in a highly cooperative manner, as indicated by (1) dependence of the initial kinetics of histone removal upon heparin concentration, (2) analysis of DNA and histones in the fractions obtained from differential sedimentation of heparin-treated nuclei, and (3) analysis of the products from heparin-treated nuclei by equilibrium centrifugation in metrizamide density gradients. The results suggest rapid procedures for using heparin as an agent for studying the accessibility of histones in chromatin of intact nuclei. The relationship of these results to current models of chromatin structure is discussed.
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London RE, Hildebrand CE, Olson ES, Matwiyoff NA. Carbon-13 nuclear magnetic resonance spectroscopy of suspensions of chinese hamster ovary cells specifically enriched with (methyl-13C)choline. Biochemistry 1976; 15:5480-6. [PMID: 999821 DOI: 10.1021/bi00670a009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Hildebrand CE, Walters RA. Rapid assembly of newly synthesized DNA into chromatin subunits prior to joining to small DNA replication intermediates. Biochem Biophys Res Commun 1976; 73:157-63. [PMID: 999696 DOI: 10.1016/0006-291x(76)90510-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Walters RA, Tobey RA, Hildebrand CE. Chain elongation and joining of DNA synthesized during hydroxyurea treatment of Chinese hamster cells. Biochim Biophys Acta 1976; 447:36-44. [PMID: 963081 DOI: 10.1016/0005-2787(76)90093-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We have previously presented evidence that hydroxyurea treatment of synchronized G1 Chinese hamster cells did not prevent the entry of cells into the DNA synthetic period but that the DNA synthesized during this period (in which total DNA synthesis was severely depressed) was quite small (Walters, R.A., Tobey, R.A. and Hildebrand, C.E. (1976) Biochem. Biophys. Res. Com. 69, 212-217). In view of the reported effects of hydroxyurea on deoxyribonucleoside metabolism and possible relationship to control of DNA replication (Bjursell, G. and Reichard, P. (1973) J. Biol. Chem. 248,3904-3909 and Walters, R.A., Tobey, R.A. and Ratliff, R.L. (1973) Biochim. Biophys. Acta 319, 336-347), we examined the fate of DNA synthesized during and shortly after hydroxyurea treatment to determine if this DNA exhibited any kinetic behavior which might be an indicator of aberrant synthesis. We found that, upon hydroxyurea removal, DNA grew at a linear rate of 0.98 +/- 0.12 - 10(6) dalton/min (0.98 +/- 0.12 mum/min) for about 2.3h. Beginning at 2.3 h, DNA with a molecular weight approx. 1.4 - 10(8) was very rapidly integrated into bulk DNA of greater than or equal to 3.5 - 10(8) daltons. The apparent growth rate of the 1.4 - 10(8) dalton DNA was approx. 10.6 mum/min. The data suggest that, at least for this DNA, joining into bulk DNA required one-third to one-half of the S period to begin and once begun, occurred very rapidly. The possibility of inegration of replicon clusters is considered.
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