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Use of an inducible hybrid viral gene as a model for evaluating drug effects on gene expression
1Grace Cancer Drug Center, Roswell Park Memorial Institute, Buffalo, New York 14263.
Abstract:
The glucocorticoid-inducible LTL gene [Cell 38:29-38 (1984)] was used as a model target to evaluate preferential drug effects on gene expression. Specifically, the potential of bleomycin, neocarzinostatin, and actinomycin D to induce alterations in either transcriptional or posttranscriptional gene expression was assessed. A Northern blot analysis was used to measure transcriptional effects, whereas changes in posttranscriptional expression were determined through an enzymatic assay for the thymidine kinase product of the LTL gene. Comparisons of the results from these assays with results obtained from assays that evaluated drug effects on cellular RNA and protein synthesis showed that none of the drugs were capable of inducing preferential effects on transcription. However, selective drug-induced effects on the expression of thymidine kinase activity were observed.
Insights
Bleomycin, neocarzinostatin, and actinomycin D did not preferentially alter gene transcription. However, these drugs selectively affected thymidine kinase activity, indicating posttranscriptional gene expression changes.
Area of Science:
- Molecular Biology
- Pharmacology
- Gene Expression Regulation
Background:
- The glucocorticoid-inducible LTL gene serves as a model for studying drug-induced gene expression changes.
- Understanding how drugs affect gene expression at transcriptional and posttranscriptional levels is crucial for drug development and efficacy.
Purpose of the Study:
- To evaluate the potential of bleomycin, neocarzinostatin, and actinomycin D to induce preferential alterations in gene expression.
- To differentiate between drug effects on transcriptional versus posttranscriptional gene regulation using the LTL gene model.
Main Methods:
- Northern blot analysis was employed to assess drug-induced changes in gene transcription.
- Enzymatic assays for thymidine kinase activity were used to measure posttranscriptional expression of the LTL gene product.
- Comparative analysis with cellular RNA and protein synthesis assays was performed.
Main Results:
- None of the tested drugs (bleomycin, neocarzinostatin, actinomycin D) demonstrated preferential effects on gene transcription.
- Selective drug-induced effects were observed on the expression of thymidine kinase activity, indicating posttranscriptional modulation.
Conclusions:
- While these drugs do not appear to selectively target gene transcription, they can modulate posttranscriptional gene expression.
- The findings highlight the complexity of drug interactions with gene expression pathways and suggest potential for targeting posttranscriptional mechanisms.