de Grado M, Lasa I, Berenguer J
Centro de Biología Molecular Severo Ochoa, UAM-CSIC, Universidad Autónoma de Madrid, Spain.
FEMS Microbiol Lett. 1998 Aug 1;165(1):51-7. doi: 10.1111/j.1574-6968.1998.tb13126.x.
The minimal replicative origin from a 16-kbp natural plasmid of Thermus sp. ATCC 27737 is described. The 1798-bp sequence encodes a single protein (RepA) whose expression is required for replication. This requirement is extended to 200 bp upstream the coding region, which contains promoter-like sequences transcriptionally active in E. coli. Despite the absence of typical iterons, we show that an N-terminal fragment of this protein binds to a DNA fragment internal to its own coding sequence. As this DNA fragment contains an unusually A + T rich sequence surrounded by C + G rich stretches, the possible location of the replicative origin within the region encoding RepA is proposed.
