A cryptic plasmid from Shigella sonnei

J. E. Croft, P. L. Bergquist, D. Lane

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


pNZ500 is a 1.5 kb cryptic plasmid from a S. sonnei isolate. It was introduced into Escherichia coli by cotransformation, where it is maintained at about 30 copies per chromosome equivalent. Hybridization studies show that pNZ500 exhibits a high level of sequence similarity to other 1.5 kb plasmids found in different S. sonnei isolates but shares no homology with larger S. sonnei plasmids. pNZ500 shares a small degree of sequence homology with pBR322 and with pAC184. The homology with pBR322 is restricted to sequences close to the ori-bom region of this plasmid. Nevertheless, pNZ500 maintenance in E. coli is not dependent on DNA polymerase I activity, and does depend on continuing protein synthesis. pNZ500 encodes two polypeptide gene products whose monomer molecular weights are 24500 and 18000. The examination of host cells for the expression of possible plasmid phenotypes revealed no differences between cells bearing pNZ500 and plasmidless cells.

Original languageEnglish
Pages (from-to)1513-1526
Number of pages14
JournalJournal of General Microbiology
Issue number5
Publication statusPublished - 1983
Externally publishedYes


Dive into the research topics of 'A cryptic plasmid from Shigella sonnei'. Together they form a unique fingerprint.

Cite this