Bacterial Chromosome Structure and Function

We previously showed that the transcription profile of the E. coli chromosome is dictated by its structure. We proposed that the chromosome has defined structures which change the transcriptability of the constituent promoters. We are exploring to understand the structure of the E. coli chromosome by a variety of approaches.HU, an abundant highly conserved chromosome-associated protein in E. coli, has been implicated to play an architectural role in the chromosome, and to constrain supercoils in DNA. We will discuss the contribution of HU in chromosomal structure and, as a result, in global gene expression. We will also describe RNA molecules that bind to HU, and a potential role of the RNA/HU complexes in chromosome compaction.In addition, we performed chromosome conformation analysis, and discovered that GalR, a regulon specific repressor, connects distal segments of the chromosome by GalR-GalR interactions. We believe this network formation organizes the chromosome in space, thereby contributing to chromosome compaction. This is the first evidence that a transcription factor participates in folding the chromosome into a 3-D structure.