I. Dynamics of the Bacterial Chromosome
II. Escalating Infectious Disease Threat
Part II: Escalating Infectious Disease Threat
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Most bacterial cells have their genes arranged in a single circle of DNA. The circle of DNA plus some attached proteins is referred to as the bacterial chromosome. Up until quite recently, it was thought that the chromosome in the tiny bacteria cell resembled a tangled ball of yarn. It is now known that multiple factors cooperate to condense DNA into a highly dynamic assembly of supercoiled loops. Although there is variability in the lower levels of chromosome structure, the global arrangement of DNA within the cell is conserved, with individual loci arrayed along the long axis if the cell in line with their order on the genetic map. This order is maintained and propagated during DNA replication. Upon duplication of a given segment of the chromosome, it is immediately released from the replisome (the DNA replication machine) and it moves rapidly to its conserved position in the incipient daughter cell compartment. Partitioning of the bacterial chromosome thus takes place while DNA replication is in progress. Furthermore, it is becoming clear that the bacterial cell is highly organized, presenting new challenges and opportunities for the design of new antibiotics More >>
Lucy Shapiro holds the Virginia and D.K. Ludwig Chair in Cancer Research and is the Director of the Beckman Center for Genetic and Molecular Medicine at Stanford University. She received her PhD in Molecular Biology from the Albert Einstein College of Medicine. She joined the faculty at Stanford University School of Medicine in 1989 and served as the founding chair of the Department of Developmental Biology. Earlier, she was the Higgins Professor and Chair of the Department of Microbiology at the College of Physicians and Surgeons at Columbia University. She is a member of the US National Academy of Sciences.