The structure and function of a eukaryotic promoter.

Transformation, or DNA-mediated gene transfer, permits the stable introduction of new genetic information into a cell and therefore provides an opportunity to examine the expression of exogenous DNA sequences in the transformed host. A series of deletion mutants to analyze the sequences required for accurate and quantitative in vivo transcription of the herpes simplex virus (HSV) thymidine kinase (tk) gene has been constructed. Control of the efficiency of transcription as well as rough specification of the sites of initiation reside within sequences 40-110 nucleotides from the tk structural gene. The sequences responsible for induction of tk mRNA overlap this transcriptional control region. Analysis of the conformation of the integrated tk gene in the chromosome reveals that these DNA sequences are exquisitely sensitive to nuclease attack. The major heat shock gene of Drosophila and the human beta globin gene have also been introduced into murine cells to identify sequences responsible for induction of these finely regulated genes.