Mutational spectra in the tk gene of mouse lymphoma cells induced by acrylamide / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of acrylamide (AA)-induced mutational spectra in the tk gene of mouse lymphoma cells.</p><p><b>METHODS</b>L5178Y3.2.7c-tk(+/-) cells were treated with AA at different concentrations. Mutational spectra of tk locus were analyzed by the mouse lymphoma assay (microtiter procedure), and frequency of loss of heterozygosity (LOH) analysis with allele special PCR. Subsequently determined the DNA sequence of negative LOH's colonies induced by AA.</p><p><b>RESULTS</b>The LOH of mutants derived from AA induction was 78.8%, and showed a good dose-response relationship in large colonies. The occurrence of LOH of large colonies at lower doses (150 microg/ml and 300 microg/ml) were 25.0% and 33.3% respectively which were significantly different from those of control (66.7%), and at higher doses (600 microg/ml and 750 microg/ml) were 77.8% and 85.7%. By Sequence analysis showed that AA-induced point mutations were mainly base substitutions, and most of them were T:G-->G:T transversions.</p><p><b>CONCLUSION</b>Functional tk allele gene loss is major mutational event in both spontaneous and induced tk mutants. And point mutations were base substitution.</p>

Effects of total alkaloids of Tripterygium hypoglaucum Hutch on tk gene of mouse lymphoma cells / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effects of total alkaloids of Tripterygium hypoglaucum Hutch (THH) on the tk gene of mouse lymphoma cells.</p><p><b>METHOD</b>L5178Y cells were infected with total alkaloids of THH with different concentrations and put into single-cell wells at different time phases. Then the numbers of positive wells were counted and the cell plating efficiency, relative suspension growth and mutation frequency were determined.</p><p><b>RESULT</b>Total alkaloids of THH (0.1-2.0 g x L(-1)) induced tk locus mutation with mutation frequency 2-9 times higher than that of spontaneous mutation frequency of L5178Y cells. There were two different phenotypes of mutation colonies, large colony and small colony, but the main colony was large colony. This phenomenon might be related with the mutagenesis of THH.</p><p><b>CONCLUSION</b>Total alkaloids of THH can exert toxicity and mutagenic effects on tk gene in L5178Y cells, and there may be range limit in gene mutation.</p>