The long term goal of the proposed research is to determine the mechanisms whereby plasmid gene expression is regulated in bacterial systems. In the coming year we will strive to accomplish the following: 1. Mapping of the major promoters in ColE1. 2. Sequence analysis of a region of the ColE1 chromosome which we have hypothesized to contain two promoters. 3. Effects of supercoiling, ppGpp and ColE1 gene products on regulating plasmid transcription.