Accumulation of gadd153 mRNA is strongly stimulated in mammalian cells by 
treatments which arrest growth or damage DNA (A. J. Fornace, Jr. et al., Mol. 
Cell. Biol., 9: 4196-4203, 1989). In previous studies, we demonstrated that the 
increased expression of gadd153 following treatment with several DNA-damaging 
agents was mediated transcriptionally (J. D. Luethy et al., J. Biol. Chem., 265: 
16521-16526, 1990). To better define the specificity of this response, we have 
established a sensitive reporter system in which we have stably integrated a 
chimeric gene containing the gadd153 promoter linked to the coding region of the 
chloramphenicol acetyltransferase (CAT) gene into the genome of HeLa cells. 
Transcriptional activation from the gadd153 promoter was monitored by 
determining levels of CAT activity in cellular lysates prepared from 
gadd153CAT/HeLa cells treated with a variety of agents. The gadd153 promoter was 
strongly activated by a broad spectrum of genotoxic agents including UV-mimetic 
agents, DNA-cross-linking and alkylating agents, DNA intercalators, and 
topoisomerase inhibitors. Of the DNA-damaging agents tested, only X-irradiation 
and bleomycin treatments failed to induce gadd153 promoter activity. Agents 
which inhibit replication and cell division and agents which otherwise result in 
cytotoxicity or growth arrest also had little influence on gadd153 promoter 
activity. Expression of the gadd153CAT chimeric gene in xeroderma pigmentosum 
Group A cells, which are deficient in nucleotide excision DNA repair of 
pyrimidine dimers, was maximally induced at UV doses at least 6-fold lower than 
those required for similar induction in repair-proficient HeLa cells. However, 
the methyl methanesulfonate-induced gadd153 promoter activities were similar in 
both cell lines. Novobiocin pretreatment inhibited both UV- and methyl 
methanesulfonate-induced gadd153CAT expression. Collectively, these data 
indicate that: (a) the gadd153 promoter is activated rapidly and specifically by 
DNA damage; (b) the altered DNA structure is the inducing signal for the 
activation of the signal transduction pathway responsible for enhanced gadd153 
expression; and (c) regulation of gadd153 by growth arrest is distinct from that 
of DNA damage. Thus, the gadd153CAT/HeLa cells are a useful model for examining 
the molecular mechanisms associated with the response to DNA damage and provide 
a reporter system for the screening of potential genotoxic agents.