This award will support collaborative research between a group of U.S. and Belgian biochemists. The U.S. investigators are Dr. N. P. Higgins, University of Alabama at Birmingham and Dr. Martin Pato, University of Colorado Health Science Center. The Belgian researcher is Dr. Ariane Toussaint, Free University of Brussels. The long range goal of this project is to understand regulation of genetic transposition in bacterial populations. The Mu transposase and semi-essential genes participate in a highly efficient replication-transposition reaction in vivo. In this __ ____ project, experiments will be performed to analyze the transposase and early genes that influence Mu biology at the stages of the transcription and DNA synthesis. Objectives of the collaborative work include i) expression, ii) purification and iii) characterization of DNA binding proteins encoded by the virus. The investigators will extend joint efforts to chromosome-associated proteins (HU and other "histone-like" proteins) of E. coli and _ ____ Salmonella typhimurium. This approach will expand basic knowledge __________ ___________ of the chromosomal proteins that organize a functional folded nucleoid. The three investigators run laboratories that have demonstrated complementary expertise in all of the areas to be studied. Systems involving purified proteins for analyzing Mu transcription and replication in vitro are established in __ _____ Birmingham. Methods for analyzing Mu transcription and replication in vivo are established in Denver. The group in Brussels has genetic strategies for selecting mutants and carrying out the genetic dissection of proteins related to Mu biology. By coordinating experiments at the three sites, the investigators can test a hypothesis genetically and measure predicted behavior in ___ vitro and in vivo in a relatively short period of _____ _______ time.