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標題: Gene Expression and Regulation of Bioluminescence:Functional Analysis of the Regulatory Region of the lux Regulon from Vibrio fischeri.
螢光基因之表現與調節機制: Vibrio fischeri lux regulon 調節區域之功能分析
作者: 塗曼鈴
Tu, Man-Ling
關鍵字: Vibrio fischeri;lux regulon;調節區域;調節機制;Vibrio fischeri;lux regulon;regulatory region;regulatory mechanism
出版社: 分子生物研究所
We use the gene order rearrangement to analyze the regulatory
region (R&R) of the lux regulon from Vibrio fischeri reveals
that the expression of the L-promoter is much stronger than
that of the R-promoter. The results of glucose repression
experiment illustrate that the expression of the L-operon is
enhanced by cAMP-CRP. In trans complementation tests elucidat
that the LuxR- AI complex could enhance the expression of the
two promoters by binding on the motif binding site of the R&R.
The evidences of site-directed mutagenesis reveal that the LuxR-
AI could bind on the R1-palindrome to enhance the expression of
the divergent pro- moters. In addition, site-directed
mutagenesis method was used to modify the R2-reversed repeat,it
shows no effect on the of the divergent promoters. So far,the
function of the repeat on the R&R of the lux regulon is not
clearly known yet.

已知Vibrio fischeri lux regulon之基因排列為<-luxR-R&R- luxI-
luxC-luxD-luxA-luxB-luxE-luxG->,其中R&R (regulatory re- gion)
為調節區域,是本實驗的研究方向;並以V. harveyi luxA-luxB作研究,
以研究調節區域之各項功能。 由結果顯見 L-promoter 之表現較為強勢
,而R-promoter則較為弱勢。 就L-promoter 而言,在L-pro- moter 附
近有一 cAMP-CRP 複合體結合位,其促進方向與 L-promoter方向相同,
經由 glucose repression 試驗,肯定 L-promoter 表現極強是由於
cAMP-CRP 複合體之誘導作用;而 R-promoter 表現極弱,推測其原因在
於其 DNA 序列及其附近構形造成 RNA polymerase 無法認辨。由 in
trans 互補試驗,顯示 LuxR 及 autoinducer 共同存在可誘導雙啟動子
之表現,因而推測 LuxR 及 autoinducer 可形成 LuxR-AI複合體,並作
用於調節區域。經定點突變,肯定 LuxR-AI 複合體結合於 R1-
palindrome,而其誘導方式就 R-promoter 而言,推測 RNA poly-
merase 可藉由 LuxR-AI 複合體結合於 R1-palindrome,而加速 RNA
polymerase 認辨前行至 -10 區域,於是增強其轉錄作用;至於 L-pro-
moter 則可能是 LuxR-AI 複合體加強 cAMP-CRP 複合體之結合能力,於
是 L-promoter 之表現更強。 此外,本實驗亦推測 cAMP-CRP 及 LuxR-
AI 複合體可協調助於對方與調節區域之結合,即有 coordinarily co-
operation 作用之現象。 在 cAMP-CRP 及 LuxR-AI 複合體結合位間尚
有一 R2-reversed repeat,以定點突變方式改變此區域對雙啟動子表現
Appears in Collections:分子生物學研究所

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