organelles. Thus, the formation of the polyhedral organelles does not appear to be dependent upon their association with the diol dehydratase enzyme and consequently does not appear to require the pduC gene.

      Complementation studies conducted in this strain demonstrated that plasmid encoded diol dehydratase could be packaged into polyhedral organelles. However, complementation studies conducted inpduA and pduB insertion mutants were unsuccessful. Aberrant structures were observed in both instances, which could be interpreted to suggest that the downstream expression from the tetracycline-inducible promoters of the TPOP insertion was not similar enough to wild type levels to support formation of the polyhedral organelles. Alternatively, the proteins involved in polyhedral organelle formation could be required in strict ratios for correct assembly or the expression of downstream genes could be dependent upon expression of the pduA and pduB genes. The answers to these questions could be answered better by conducting complementation studies in precise nonpolar deletion mutants.

  PduA is a Shell Protein Required for the Formation of the Polyhedral Organelles

      The second part of this study (Chapter 3) investigated the role of the PduA protein in the formation of the polyhedral organelle. Experiments conducted using antiserum generated against purified recombinant PduA protein demonstrated that the PduA protein localized to the periphery of the polyhedral organelles, indicating that it was a component of the organelle shell. Taking cues from the studies conducted in Chapter 2, complementation of the pduA gene was studied in a precise nonpolar deletion mutant. Expression of plasmid-encoded PduA in this strain resulted in the formation of both normal and aberrant polyhedral organelles. Although not all of the polyhedral organelles were perfectly formed, the degree of complementation seen in this deletion strain was