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Title:Molecular genetic analysis of puf andpuc operon expression in Rhodobacter sphaeroides 2.4.1
Author(s):Lee, Jeong Kug
Doctoral Committee Chair(s):Gardner, Jeffrey F.
Department / Program:Microbiology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Molecular
Biology, Microbiology
Abstract:The deletion of the puf intercistronic terminator resulted in both the loss of the smallest 0.5-kilobase (kb) puf transcript in addition to an approximate 10-fold increase in transcriptional read-through of the mutated region to more distal pufL gene, suggesting that the proximal intercistronic stem-loop functions as a transcription terminator.
The puc operon encodes 2.3- and 0.5-kb transcripts. The 2.3-kb transcript extends from the same 5$\sp\prime$ end (117 nucleotides from the start of pucB) as that of the 0.5-kb transcript to approximately 1.8 kb downstream of the pucBA genes, and encodes gene product(s) involved in post-translational expression of the pucBA gene products involved in the formation of B800-850 complex.
A 629-base pair DNA region upstream of the 5$\sp\prime$-ends of the two puc-specific transcripts encompasses two functionally separable cis-acting domains: the upstream regulatory region (URS, $-$629 to $-$150) responsible for oxygen and light control of puc operon transcription, and the more proximal downstream regulatory region (DRS, $-$150 to $-$1) containing putative IHF/FNR-binding sites ($-$129 $-$105), putative promoter(s) ($-$92 and $-$57), and operator(s) ($-$52 $-$35 and $-$27 $-$10) involved in oxygen control of puc operon transcription. In addition, data reveal a direct interaction between the URS ($-$629 $-$150) and the DRS ($-$150 $-$1). A trans-acting factor involved in O$\sb2$ control of puc operon transcription acted upon the puc URS, while a second trans-acting factor(s) acted upon both the puc URS and DRS. The former trans-acting factor was genetically mapped to a 2.2-kb DNA fragment located within the carotenoid gene cluster, while the genetic map of the second trans-acting factor was localized to a 7.0-kb DNA fragment containing the puhA gene and its flanking DNA (6.3 kb).
Issue Date:1992
Rights Information:Copyright 1992 Lee, Jeong Kug
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9215846
OCLC Identifier:(UMI)AAI9215846

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