ISSN:
1617-4623
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Summary A 3.7 Mdal DNA fragment of plasmid ColIb which carried all the genetic information determining the growth inhibition of bacteriophage BF23 (Ibf phenotype) but not for production of colicin Ib protein (Cib) and immunity to colicin Ib (Imm) was cloned in the pBR322 vector. We also cloned the 8.7 Mdal DNA fragment that was responsible for both Cib and Imm but not for Ibf phenotype. Thus, these results clearly showed that the gene(s) determining Ibf are different from those for Cib or Imm. Dissection of the Ibf-DNA revealed that at least two genes, ibfA and ibfB, were involved in the Ibf phenotype. The ibfA gene was mapped within a 1.45 Mdal EcoRI DNA fragment (E-13); mutation of this gene by deletion or by insertion of Tn5, a kanamycin resistance transposon, resulted in the complete loss of Ibf phenotype. The ibfB gene, mapped around a 0.32 Mdal HindIII DNA fragment (H-7), was found to be active in trans to ibfA, and its function seemed to promote ibfA activity. The genetic map of the ibf genes in relation to other ColIb markers was determined as ibfB-ibfA-imm-cib. Attempts to identify the ibfA gene product in the minicell system, however, did not succeed.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00333784
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