Cloning and characterization of the pilR and pilS genes of Xanthomonas campestris pv. citri
| Autor: | Chun-Ping Chou, 周峻平 |
|---|---|
| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 The pilR and pilS genes of Xanthomonas campestris pv. citri have been cloned and sequenced. Two open reading frames encoded 464 and 618 amino acids that share 68 % and 40 % identities with PilR and PilS proteins of Pseudomonas aeruginosa, respectively. Both pilR and pilS mutants of X. c. pv. citri that were generated by gene replacement resulted in decreased expression of pilA according to Western blot analysis. Overexpressed PilR in X. c. pv. citri functioned as an activator of pilA expression and led to the restoration of the filamentous bacteriophage cf infection. Unexpectedly, overexpression of pilS in X. c. pv. citri brought about decreased expression of the pilA gene and had no restoration of cf infection. Furthermore, transcription of a fusion between the promoter of pilA and the luxAB gene was remarkably repressed in pilR mutant but not pilS mutant, suggesting that PilR might be one of regulators of pilA expression in X. c. pv. citri. In additions, it was also indicated that high levels of PilR greatly activate transcription of the pilA-luxAB fusion. On the basis of this study, it implicated that PilR up-regulates the expression of pilA gene in X. c. pv. citri. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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