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R72H 片段共通存在於各腸炎弧菌中，且已開發為檢測腸炎弧菌之高專
一性探針。為求探討 R72H 在腸炎弧菌中所扮演的角色，我們以
Inverse-PCR 的方式，由已知序列中設計引子，增幅其 3'' 及 5'' 之側邊
序列並予以定序。經分析與比對序列後，發現 R72H 之5'' 側邊序列為一
rRNA operon，而這個 rRNA operon 當中基因的排列方式為 23S rRNA-5S
rRNA-tRNA，與 E. coli 之 rRNA operon 中基因的排列方式相似。此一
rRNA operon末端的 tRNA 基因為 Asp-tRNA 基因。在 tRNA 基因之後則
有與 E. coli rRNA operon相似的 terminator 構造。由 Northern blot
與 reverse transcription- polymerase chain reaction 等針對 R72H
的功能分析結果中，發現 R72H 的 5'' 端所在的序列中沒有功能表現。而
R72H 的 3'' 端與其 3'' 側邊序列，經序列比對後，發現與 E. coli 的
phosphatidyl-serine synthase (pss) 基因之 3'' 端的序，有 58% 的相
似度，其轉錄 的方向與 rRNA operon 的轉錄方向相反，R72H 序列中與
pss 基因相似的序列之後，則發現有一 terminator 的構造位於其後。由
本研究的結果中，歸納出 R72H 在染色體上位於 rRNA operon 之後，R72
H 片段 5'' 端的序列與已發表的基因序列沒有高相似度，為一段沒有功能
表現的核酸片段; R72H 序列之 3'' 端與其 3'' 側邊序列可能為一與 pss
基因相似之基因片段。
The R72H fragment is a conserve sequence in Vibrio
parahaemolyticus and has been used as a highly specific probe in
detection of the Vibrio parahaemo-lyitcus. To understand what
function the R72H takes in Vibrio parahaemolyticus,we amplified
the 5'' and 3'' flanking sequences of the R72H fragment using
Inverse-PCR method and sequenced the flanking sequences. After
sequence analysis and comparison to the sequences in DataBank,
we found that the 5'' flanking sequence of R72H is a rRNA operon.
In this rRNA operon, the gene arrangement is 23S rRNA-5S rRNA-
tRNA, like the rRNA operon in E. coli. The tRNA gene of this
rRNA operon is Asp-tRNA. And after the tRNA gene, there isa
stem-loop structure, like a terminator as the rRNA operon in E.
coli. The function of R72H and it''s 3'' flanking sequence were
studied by the Northernblot and reverse transcription-polymerase
chain reaction. The results indicatedthat the 5'' part of R72H
was not coded for mRNA. The 3''part and the 3'' flankingsequences
of the R72H have 58% identity to the phosphatidyl-serine
synthase (pss) gene in E. coli. And its orientation of the
sequence for coding is anti tothe rRNA operon, as the pss in E.
coli. After the pss-like sequence of the R72Hfragment, we found
a stem-loop structure, like a terminator. Based on our results,
we conclude that the R72H is located after a rRNA operon in the
chromosome of Vibrio parahaemolyticus, and is composed with a
non-coding region and a pss-like gene.
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