The positive regulator of gene expression specified by bacteriophage lambda gene Q is proposed to work by counteracting a transcriptional termination event, a mechanism similar to that suggested previously for the lambda gene N regulator. I propose to test this hypothesis by purifying the gene Q protein and demonstrating its activity in a cell-free system which utilizes purified components. By producing specific fragments of the lambda genome with restriction endonucleases, I hope to isolate the site of control in order to study the interaction of Q protein with DNA or RNA and learn the biochemical details of the control process. In addition, I intend to utilize this DNA fragment to directly test the elongation hypothesis in vivo.