Genetic and physiological studies of the Vibrio fischeri lux regulon /
The LuxR protein is the transcriptional activator of the lux
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739364241&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The LuxR protein is the transcriptional activator of the lux regulon (luxr luxlCDABEG) from a bioluminescent marine bacterium Vibrio fischeri. The lux gene cluster has been cloned in Escherichia coli and the regulation features shown to function normally. To function, LuxR requires a small diffusible molecule termed autoinducer. In the presence of autoinducer, LuxR activates Piux/ transcription from its binding site which overlaps with the -35 region of the P/ux/ promoter. The structure of LuxR is modular, with the N- terminal domain being necessary for autoinducer response and multimerization and the Cterminal domain required for activation and DNA binding. In this study, we provide genetic evidence for direct interactions between LuxR and RNA polymerase. Our results strongly suggest that LuxR functions as a multimer, possibly as a dimer. Using mutational analysis, we demonstrate that the C-terminal domain contains a helix-turn-helix motif required for direct LuxR-DNA interactions and activation by LuxR. The region upstream of the helix-turn-helix motif is also necessary for activation and DNA binding. The unconserved C-terminal "tail" is dispensable for LuxR function. Our results contribute more information to the understanding of structure and function of LuxR. Mutants, described in this work, provide a useful tool for further characterization of LuxR in vitro. |
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| Item Description: | Vita. "Major Subject: Biochemistry". |
| Physical Description: | xiii, 171 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 157-170. |