Dr Jon Bath

Abstract:

We demonstrate the use of rolling circle replication to template linear DNA arrays whose sizes bridge the gap between nanometre-scale self-assembly and top-down lithographic fabrication. Using rolling circle replication we have produced an oligonucleotide containing several hundred repeats of a short sequence motif. On this template we have constructed, by self-assembly, an array consisting of two parallel duplexes periodically linked by antiparallel Holliday junctions. We have observed arrays up to 10 νm in length by atomic force microscopy. © 2005 IOP Publishing Ltd.

Abstract:

A system of DNA "tiles" that is designed to assemble to form two-dimensional arrays is observed to form narrow ribbons several micrometers in length. The uniform width of the ribbons and lack of frayed edges lead us to propose that they are arrays that have curled and closed on themselves to form tubes. This proposal is confirmed by the observation of tubes with helical order.

Abstract:

DNA transport is important in various biological contexts--particularly chromosome segregation and intercellular gene transfer. Recently, progress has been made in understanding the function of a family of bacterial proteins involved in DNA transfer, and we focus here on one of the best-understood members, SpoIIIE. Studies of SpoIIIE-like proteins show that they might couple DNA transport to processes such as cell division, conjugation (mating) and the resolution of chromosome dimers.

Abstract:

The SpoIIIE protein of Bacillus subtilis is required for chromosome segregation during spore formation. The COOH-terminal cytoplasmic part of SpoIIIE was shown to be a DNA-dependent adenosine triphosphatase (ATPase) capable of tracking along DNA in the presence of ATP, and the NH(2)-terminal part of the protein was found to mediate its localization to the division septum. Thus, during sporulation, SpoIIIE appears to act as a DNA pump that actively moves one of the replicated pair of chromosomes into the prespore. The presence of SpoIIIE homologs in a broad range of bacteria suggests that this mechanism for active transport of DNA may be widespread.