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Titolo:
DIFFERENT CAPACITIES FOR RECOMBINATION IN CLOSELY-RELATED HUMAN LYMPHOBLASTOID CELL-LINES WITH DIFFERENT MUTATIONAL RESPONSES TO X-IRRADIATION
Autore:
XIA F; AMUNDSON SA; NICKOLOFF JA; LIBER HL;
Indirizzi:
HARVARD UNIV,SCH PUBL HLTH,DEPT CANC BIOL,665 HUNTINGTON AVE BOSTON MA 02115 HARVARD UNIV,SCH PUBL HLTH,DEPT CANC BIOL BOSTON MA 02115
Titolo Testata:
Molecular and cellular biology
fascicolo: 9, volume: 14, anno: 1994,
pagine: 5850 - 5857
SICI:
0270-7306(1994)14:9<5850:DCFRIC>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
DOUBLE-STRAND BREAK; MOUSE LYMPHOMA-CELLS; THYMIDINE KINASE LOCUS; HAMSTER OVARY CELL; IONIZING-RADIATION SENSITIVITY; HETEROZYGOUS AUTOSOMAL LOCUS; RESISTANT TFT MUTANTS; HOMOLOGOUS RECOMBINATION; MAMMALIAN-CELLS; V(D)J RECOMBINATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
86
Recensione:
Indirizzi per estratti:
Citazione:
F. Xia et al., "DIFFERENT CAPACITIES FOR RECOMBINATION IN CLOSELY-RELATED HUMAN LYMPHOBLASTOID CELL-LINES WITH DIFFERENT MUTATIONAL RESPONSES TO X-IRRADIATION", Molecular and cellular biology, 14(9), 1994, pp. 5850-5857

Abstract

WIL2-NS and TK6 are two distinct human lymphoblast cell lines derivedfrom a single male donor. WIL2-NS cells are significantly more resistant to the cytotoxic effects of S-irradiation but considerably more sensitive to induced mutation. In an effort to determine the mechanisticbasis for these differences, we analyzed the physical structures of thymidine kinase (tk)-deficient mutants isolated after X-ray treatment of tk heterozygotes derived from TK6 and the more mutable WIL2-NS. Southern analysis showed that while 84% of TK6-derived mutants had arisenby loss of heterozygosity. (LOH), all 106 mutants from WIL2-NS derivatives arose with LOB at tk and all but one showed LOH at other linked loci on chromosome 17. We adapted a fluorescence in situ hybridizationtechnique to distinguish between LOH due to deletion, which results in retention of only one fk allele, and LOH due to a mechanism involving the homologous chromosome (e.g., recombination), which results in the retention of two alleles. Among the LOH mutants derived that were analyzed in this way, 9 of 26 from WIL2-NS and 11 of 17 from TK6 cell lines arose by deletion. The remaining mutants retained two copies of the rk gene and thus arose by a mechanism involving the homologous allele. Since many of these mutants arising by a homologous mechanism retained partial heterozygosity of chromosome 17, they must have arisen by recombination or gene conversion, and not chromosome loss and reduplication. Finally, the recombinational capacities of WIL2-NS and TK6 werecompared in transfection assays with plasmid recombination substrates. Intermolecular recombination frequencies were gl eater in WIL2-NS than in TK6. These data are consistent with a model suggesting that a recombinational repair system is functioning at a higher level in WIL2-NS than in TK6; the greater mutability of the tk locus in WIL2-NS results from more frequent inter- and intramolecular recombination events.

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Documento generato il 26/09/20 alle ore 11:02:14