Functional study of Escherichia coli DUF28 proteins in oxidative stress response

碩士 === 國立臺灣大學 === 植物科學研究所 === 99 === DUF28 protein family ubiquitously exists in all organisms, except Archaea; however, information on their function is very limited. Previous studies demonstrated that DUF28 is involved in Pseudomonas aeruginosa swarming motility and quorum sensing, and functions a...

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Main Authors: Yun-Lu Lai, 賴芸璐
Other Authors: 鄭秋萍
Format: Others
Language:zh-TW
Published: 2011
Online Access:http://ndltd.ncl.edu.tw/handle/88478186458673565422
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spelling ndltd-TW-099NTU053660072015-10-28T04:11:42Z http://ndltd.ncl.edu.tw/handle/88478186458673565422 Functional study of Escherichia coli DUF28 proteins in oxidative stress response 大腸桿菌DUF28蛋白質在氧化逆境反應之功能研究 Yun-Lu Lai 賴芸璐 碩士 國立臺灣大學 植物科學研究所 99 DUF28 protein family ubiquitously exists in all organisms, except Archaea; however, information on their function is very limited. Previous studies demonstrated that DUF28 is involved in Pseudomonas aeruginosa swarming motility and quorum sensing, and functions as a translational activator of COX I in mammals. Interestingly, this study revealed the existence of two DUF28 homologs in some eubacteria. The aim of this study was to investigate functions of the two E. coli DUF28 proteins, namely YeeN and YebC, particularly their function in oxidative stress responses. Sequence comparisons revealed that bacterial DUF28 proteins shared low similarity, implying these proteins may preserve conserved tertiary structure. Null mutants ΔyeeN and ΔyebC both displayed increased swarming and swimming activities, while only ΔyeeN conferred increased tolerance to paraquat. Complementation assays further confirmed functions of these two proteins in motility and paraquat tolerance. Promoter analysis demonstrated that yeeN has its own promoter that can be repressed by oxidative stress. yebC promoter functioned only later growth phase and was not regulated by the test oxidative stress treatments. Protein localization analysis showed that accumulation and stress conditions could lead to polar distribution of YeeN in cytosol, while YebC uniformly distributed in cytosol and became polar distribution in a fragmented manner only at the death growth phase. Furthermore, by investigating the putative regulatory genes that may be involved in yeeN regulation, this study showed that recA could regulate yeeN under oxidative stress treatment. relA could upregulate yeeN expression under normal condition, but may not be involved in yeeN regulation under oxidative stress. On the other hand, hns could downregulate yeeN expression in late growth phase, and may regulate yeeN in flagella biosynthesis. Taken together, these results indicate that YeeN and YebC both function in bacterial motility, while YeeN also plays an important role in oxidative stress responses. This study is the first to uncover common as well as distinct functions of two bacterial DUF28 proteins. 鄭秋萍 2011 學位論文 ; thesis 93 zh-TW
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language zh-TW
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description 碩士 === 國立臺灣大學 === 植物科學研究所 === 99 === DUF28 protein family ubiquitously exists in all organisms, except Archaea; however, information on their function is very limited. Previous studies demonstrated that DUF28 is involved in Pseudomonas aeruginosa swarming motility and quorum sensing, and functions as a translational activator of COX I in mammals. Interestingly, this study revealed the existence of two DUF28 homologs in some eubacteria. The aim of this study was to investigate functions of the two E. coli DUF28 proteins, namely YeeN and YebC, particularly their function in oxidative stress responses. Sequence comparisons revealed that bacterial DUF28 proteins shared low similarity, implying these proteins may preserve conserved tertiary structure. Null mutants ΔyeeN and ΔyebC both displayed increased swarming and swimming activities, while only ΔyeeN conferred increased tolerance to paraquat. Complementation assays further confirmed functions of these two proteins in motility and paraquat tolerance. Promoter analysis demonstrated that yeeN has its own promoter that can be repressed by oxidative stress. yebC promoter functioned only later growth phase and was not regulated by the test oxidative stress treatments. Protein localization analysis showed that accumulation and stress conditions could lead to polar distribution of YeeN in cytosol, while YebC uniformly distributed in cytosol and became polar distribution in a fragmented manner only at the death growth phase. Furthermore, by investigating the putative regulatory genes that may be involved in yeeN regulation, this study showed that recA could regulate yeeN under oxidative stress treatment. relA could upregulate yeeN expression under normal condition, but may not be involved in yeeN regulation under oxidative stress. On the other hand, hns could downregulate yeeN expression in late growth phase, and may regulate yeeN in flagella biosynthesis. Taken together, these results indicate that YeeN and YebC both function in bacterial motility, while YeeN also plays an important role in oxidative stress responses. This study is the first to uncover common as well as distinct functions of two bacterial DUF28 proteins.
author2 鄭秋萍
author_facet 鄭秋萍
Yun-Lu Lai
賴芸璐
author Yun-Lu Lai
賴芸璐
spellingShingle Yun-Lu Lai
賴芸璐
Functional study of Escherichia coli DUF28 proteins in oxidative stress response
author_sort Yun-Lu Lai
title Functional study of Escherichia coli DUF28 proteins in oxidative stress response
title_short Functional study of Escherichia coli DUF28 proteins in oxidative stress response
title_full Functional study of Escherichia coli DUF28 proteins in oxidative stress response
title_fullStr Functional study of Escherichia coli DUF28 proteins in oxidative stress response
title_full_unstemmed Functional study of Escherichia coli DUF28 proteins in oxidative stress response
title_sort functional study of escherichia coli duf28 proteins in oxidative stress response
publishDate 2011
url http://ndltd.ncl.edu.tw/handle/88478186458673565422
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