An analysis of 5' regulatory sequences of the hamster APRT gene.

Abstract

Regulation of gene expression is mediated by the interaction between cis-acting elements in the promoter region of a gene and trans-acting protein factors which recognize and bind to these cis-acting factors. The typical eukaryotic gene contains a TATA sequence, which directs the site of RNA polymerase 2 binding to such elements, and a CAAT sequence, near the site of transcription initiation. Some genes also have “enhancer” sequences, which appear to be possible protein binding sites that enhance the level of transcription (reviewed in Serfling et al. 1985). In an analysis for such signals in the published sequences of the aprt gene from hamster (Nalbantoglu et al. 1986, Park and Taylor, 1988), mouse (Dush et al. 1985) and humans (Broderick et al. 1987), we have not been able to detect such cis-acting sequences. Thus regulation of expression of the aprt gene must occur by other mechanisms, or by signals still uncharacterized. The aprt gene from all of the above organisms, however, does contain GC rich sequences which have been characterized as putative SP1 binding sites, and which play a role in transcription regulation (Dynan and Tijian 1983, Dynan 1986).