# MOLECULAR ANALYSIS OF CARCINOGEN-INDUCED MUTATIONS

> **NIH NIH R01** · UNIVERSITY OF WISCONSIN-MADISON · 1989 · $102,734

## Abstract

Detailed knowledge of the mechanisms by which chemical carcinogena induce
mutations in mammalian cells is a prerequisite for understanding the
initiating events of carcino-genesis. As an approach to elucidating the
molecular basis for carcinogen-induced mutations, recombinant DNA shuttle
vectors were developed for analysis of mutagenesis in human
lymphoblastoid cells. These shuttle vectors, which contain the oriP
element from Epstein-Barr virus, a bacterial plasmid replicon, and the
herpes simplex virus type 1 thymidine kinase (HSV-tK) gene, replicate as
plasmids and are stably maintained in human cells. Mutations in the
target HSV-tK gene are fixed by replication of the vector in human cells
and mutant plasmids are selected after transformation of E. coli. this
approach allows the facile molecular characterization of carcinogen-
induced and spontaneous mutations and the determination of the roles in
mutagenesis of functional characteristics of the target gene and the host
cell genetic background.

These oriP-tk shuttle vectors will be used to address four specific
questions related to mutagenesis in human cells. 1) Does the spectrum of
mutations induced by aralkylated bases in DNA depend on the structure of
the DNA adduct? The efficiencies and specificities for mutagenesis in
human cells will be compared for N-hydroxy-2-amino-fluorene, N-hydroxy-4-
aminobiphenyl, N-hydroxy-N'-acetylbenzidine and N-benzoyloxy-N-methyl-4-
aminoazobenzene. 2) Does transcriptional expression of the target gene
influence the frequency, distribution, or specificity of chemically-
induced mutations? Mutagenesis by N-ethyl-N-nitrosourea and N-hydroxy-2-
aminofluorene will be studied using plasmids which result in a high level
of HSV-tk gene expression or no detectable transcription in human cells.
The relative importance of DNA repair, differential DNA modification, and
interaction between the replication and transcription complexes will be
determined. 30 Are mutations differentially fixed by leading or lagging
strand DNA synthesis during DNA replication? The strand bias for
chemically-induced mutations will be compared for plasmid vectors in
which the direction of replication fork migration is either 5'3' or 3'5'
through the HSV-tk gene. 4) Do the frequencies of specificities of
spontaneous mutations induced in cells derived from cancer-prone Bloom's
syndrome or ataxia telangiectasia patients differ from those induced in
normal cells? Clones of plasmid-bearing cells of these three genotypes
will be isolated and propagated in culture for analysis of the rate and
specificity of spontaneous mutagenesis.

## Key facts

- **NIH application ID:** 3174935
- **Project number:** 2R01CA037166-05
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **SAM.gov UEI:** LCLSJAGTNZQ7
- **Principal Investigator:** Norman R. Drinkwater
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $102,734
- **Award type:** 2
- **Project period:** 1984-03-01 → 1993-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3174935

## Citation

> US National Institutes of Health, RePORTER application 3174935, MOLECULAR ANALYSIS OF CARCINOGEN-INDUCED MUTATIONS (2R01CA037166-05). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3174935. Licensed CC0.

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