Mutational Analysis of a Cellular Promoter Isolated by "Expression Selection"

Abstract

A cellular promoter of unknown function had been identified in rat genomic DNA by its ability to substitute for the SV40 early control region (Carbone,1985). Approximately one kb of cellular sequence, shown to contain sequences required for maximal activity, was cloned into a CAT expression vector. In order to identify regions of DNA required for maximal promoter activity, a series of 5' successive deletion mutations were constructed in the rat sequence and the mutants transfected into rat cells. CAT activity was measured to determine the transcriptional efficiencies of the deletion mutants relative to the intact promoter. This analysis identified a 180 bp fragment containing sequences required for the efficient activity of this promoter.