Sporulation and enterotoxin regulation by sigma factors in Clostridium perfringens

Clostridium perfringens is a leading cause of food poisoning annually in the United States. Ingested C. perfringens vegetative cells respond to the acidic conditions of the stomach by initiating sporulation. The process of sporulation is essential in the formation of an enterotoxin (CPE) that is responsible for the symptoms of acute food poisoning. During sporulation, the cell must differentiate into the mother cell and the forespore. Studies in Bacillus subtilis have shown that gene expression during sporulation is compartmentalized, with different genes expressed in the mother cell and the forespore. The cell-specific RNA polymerase sigma factors coordinate the development of the differentiating cell. These sigma factors are Ï F, Ï E, Ï G, and Ï K. The C. perfringens cpe gene, encoding the enterotoxin CPE, is transcribed from three promoters, P1, P2, and P3. P2 and P3 were previously proposed to be Ï E-dependent, and P1 was proposed to be Ï K-dependent based on consensus recognition sequences. In this study, mutations were introduced into the sigE and sigK genes of C. perfringens. In the sigE and sigK mutants, promoter fusion assays indicated that there was no transcription of cpe in either mutant. We also determined through transcriptional analyses that Ï E-associated RNA polymerase and Ï K-associated RNA polymerase co-regulate the transcription of each other. RT-PCR analyses indicated that Ï K is a very early acting sigma factor. The evidence provided here shows that the regulation of sporulation in C. perfringens is not the same as it is in B. subtilis, as previously proposed.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Biology

Department dc:contributor.department

Biology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2008

Author dc:creator

• Harry, Kathryn Helene

Chair dc:contributor.committeechair

• Melville, Stephen B.

Committee members dc:contributor.committeemember

• Chen, Jiann-Shin
• Schubot, Florian D.
• Yang, Zhaomin

• Clostridium perfringens
• sporulation
• sigma factors
• CPE
• food poisoning

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-05072008-115555

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/42517