Recombinant conception: does it require the DNA?
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Biomedical subjects
Publications and source records attributed to R J Warburg.
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A total of nine gerJ mutants have now been isolated in Bacillus subtilis. All are defective in their spore germination properties, being blocked at an intermediate (phase grey) stage. The dormant spores are sensitive to heating at 90 degrees C and two of the mutants (generated by transposon insertion) produce spores sensitive at 80 degrees C. The spores of these two more extreme mutants had a visibly defective cortex when studied by electron microscopy, as did some of the other mutants. During sporulation, the acquisition of spore resistance properties and the appearance of the sporulation-specific penicillin-binding protein PBP5* were delayed. A strain probably carrying a lacZ fusion to the gerJ promoter demonstrated increased expression between t2 and t4. We propose that the gerJ locus is involved in the control of one or more sporulation-specific genes.
We describe the cloning of a 6.0-kb PstI fragment of the Bacillus subtilis genome which contains much of the ilvBC-leu gene cluster. This plasmid clone and two others that had been previously isolated were characterized physically and genetically to permit the construction of a physical map of this region that is correlated to the genetic map.
An approx. 14-kb Sau3A fragment of Bacillus subtilis DNA containing the aroC and ser-22 genes has been isolated. Gene aroC is expressed in both B. subtilis and Escherichia coli and appears to contain its own promoter, allowing complementation in B. subtilis. However, expression in E. coli is dependent on insert orientation, so the direction of transcription can be deduced. The level of dehydroquinase-specific activity, encoded by the cloned aroC gene, is raised 30- to 40-fold in both E. coli and B. subtilis. The clones are stable in both E. coli and B. subtilis but appear to have undergone several large deletions during their construction.