A DNA sequence consisting of 617 base pairs (bp) from the region of the origin of replication of the broad-host range plasmid RK2 has been determined. Included within this sequence is a 393 bp HpaII restriction fragment that provides a functional origin or replication when other essential RK2 specif
Homology in the transfer origins of broad host range IncP plasmids: Definition of two subgroups of P plasmids
β Scribed by Yakobson, E. ;Guiney, G.
- Publisher
- Springer
- Year
- 1983
- Tongue
- English
- Weight
- 284 KB
- Volume
- 192
- Category
- Article
- ISSN
- 0026-8925
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β¦ Synopsis
The transfer systems of broad host range IncP plasmids are increasingly used in the genetic analysis and manipulation of many gram-negative bacteria. We have examined the structural and functional relatedness of the transfer origins of ten different broad host range plasmids which belong to the IncP incompatibility group. The data reported here, together with our results on relatedness of the replication segments of these plasmids, demonstrate that the genomes of all IncP plasmids share extensive sequence homology in the regions specifying the transfer origin and replication functions. The homology results reveal the existence of two subclasses among IncP plasmids, designated here as IncPct and IncPfl. Furthermore, a functional analysis of the transfer origins of IncP plasmids suggests strongly that the DNA-nicking relaxation complex (Guiney and Helinski 1979) is required for plasmid transfer during conjugation.
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A segment of DNA encoding incompatibility on the inc P-1 plasmid pRK248 was identified by the analysis of deletions generated in vitro, and then cloned into several unrelated and mutually compatible plasmids. These derivatives were tested for expression of P-1 incompatibility. It was demonstrated by
Transcription at various points in the trf A region of broad host range plasmid RK2 has been analysed by measuring expression of the galK gene inserted at EcoRI sites introduced previously by TB1723 transposition mutagenesis. Rightward transcription (anti-clockwise on RK2) probably from a single pro