Browsing by Subject "Bacterial chromosome organization"

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Low-Copy-Number Plasmid Partitioning in Relation to E. coli Chromosomal Organization
(2021) Wilkins, Brady
From complex multicellular organisms to the simplest of bacteria, all organisms must properly partition their DNA during cellular replication to ensure equal inheritance of genetic material. One protein key to the proper segregation of the E. coli chromosome is Structural Maintenance of Chromosomes (SMC) protein MukBEF. MukBEF condenses the chromosome along a linear, axial core that maintains the orientation of two chromosome arms. Systems for proper plasmid partitioning are typically native to the plasmid itself. For the P1 and F plasmids, the ParABS and SopABC partitioning systems ensure equal inheritance of these low-copy-number plasmids. While vastly different, one end-result of the proposed mechanisms by which MukBEF and ParABS/SopABC operate places the replication origin of the bacterial chromosome (oriC or ori) at the same cellular location as the P1/F plasmids, ensuring that these low-copy-number plasmids replicate/segregate along with the chromosome. Transposable phage Mu serves as an ideal tool to test the validity of this scenario, because Mu can only transpose to DNA it physically contacts. We placed Mu on the P1/F plasmids and monitored where it transposed upon one round of transposition. We observed an increased propensity of Mu to transpose near ori, supporting the proposition that the P1/F plasmids are physically close to ori. Does their shared location reflect the constraints of DNA partitioning in a confined space, or is it directed by SMC/Par/Sop proteins? This literature review proposes an experiment to help answer this question while exploring the segregation of chromosomal and low-copy-number plasmids.