Abstract
The transcriptional unit of the CHO APRT gene was analyzed by deletional mutants at the 3′ and 5′ end of the gene, and by deletions in the intronic regions. Two sequences 5′ to the transcription start site are involved in gene regulation. One of these is a putative Spl binding region. The other region, within 52bp of the transcription start site, as measured by DNA footprinting experiments contains a second protein binding site of 22 bp conserved in both mouse and CHO aprt genes, suggesting that it could be functionally important. This region is being analyzed by in vitro mutagenesis. The aprt structural gene and promoter was fused to the Moloney Murine Sarcoma Virus (MoMSV) LTR. These sequences contain the viral promoter and enhancer signals. The 5′ non-coding region of the aprt gene supresses activity of the Mo-MSV LTR. Deletion of the native aprt promoter allows Mo-MSV enhancer activity when the cells are grown in sodium butyrate. Under such conditions aprt enzyme activity is enhanced 20-30 fold in both transient expression assays, and in stable transformants. The overproduction of APRT has no obvious detrimental effect on cell growth.
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Taylor, M., Tang, D. & Park, J. 158 AN ANALYSIS OF 5′ REGULATORY SEQUENCES AND EFFECT OF THE MoMSV ENHANCER ON EXPRESSION OF THE APRT GENE. Pediatr Res 24, 137 (1988). https://doi.org/10.1203/00006450-198807000-00182
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DOI: https://doi.org/10.1203/00006450-198807000-00182