Record Display for the EPA National Library Catalog

RECORD NUMBER: 56 OF 1237

OLS Field Name OLS Field Data
Main Title Analysis of Trifluorothymidine-Resistant (TFT(sup r)) Mutants of L5178Y/TK(sup +/-) Mouse Lymphoma Cells.
Author Moore, M. M. ; Clive, D. ; Hozier, J. C. ; Howard, B. E. ; Batson, A. G. ;
CORP Author Health Effects Research Lab., Research Triangle Park, NC. ;Burroughs Wellcome Co., Research Triangle Park, NC. ;Florida Inst. of Tech., Melbourne.
Year Published 1985
Report Number EPA/600/J-85/153;
Stock Number PB86-100997
Additional Subjects Lymphomas ; Cells(Biology) ; Mice ; Enzymes ; Assaying ; Reprints ; Mutants ; Thymidine/trifluoro ; Mutagenesis
Holdings
Library Call Number Additional Info Location Last
Modified
Checkout
Status
NTIS  PB86-100997 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/21/1988
Collation 15p
Abstract
Three classes of TFTr variants of L5178Y/TK+/- -3.72C mouse lymphoma cells can be identified - large colony (lambda), small colony (sigma),and tiny colony (tau). The sigma and lambda mutants are detectable in the routine mutagenesis assay using soft agar cloning. The tau mutants are extremely slow growing and are quantified only in suspension cloning in microwells. Variants of all three classes have been analyzed in the process of evaluating the usefulness of the thymidine kinase locus in L5178Y/TK +/- mouse lymphoma cells for detecting induced mutational damage. 150 of 152 variants from mutagen treated cultures and 163 of 168 spontaneous mutants were TFTr when rechallenged approximately 1 week after isolation (3 weeks after induction). All of the 41 mutants assayed for enzyme activity were TK-deficient. The sigma and tau phenotypes were found to correlate with slow cellular growth rates (doubling time > 12 h), rather than from effects of the TFT selection or mutagen toxicity. Cytogenetic analysis of sigma mutants approximately 3 weeks after induction shows an association between the sigma phenotype and readily observable (at the 230-300 band level) chromosomal abnormalities (primarily translocations involving that chromosome 11 carrying the functional TK gene) in 30 of 51 induced mutants studied.