由本實驗室找到的human dynamin類蛋白，經氨基酸序列的比對得知與dynamin的結構類似，所以命名為第四類dynamin (Hdyn IV; Dymple)。同時亦與存在老鼠內的DVLP蛋白有高度的相似性。
在結構上，Hdyn IV的N端含有GTPase domain，C端則含有Coiled-Coil domain，但不含PH domain。已知Hdyn IV 基因表現在所有的真核生物，並高度表現在胞器膜小泡和內質網上，可能與粒線體的功能也有關係。
Hdyn IV含有四種不同的Hdyn IV異構物（variants），從不同的腦瘤?媯o現存在著四種不同的Hdyn IV異構物（HdynIV-wild type [WT], -11, -26, -37）。Hdyn IV-26異構物，相較於正常組織於腦腫瘤組織有高度的表現，猜測Hdyn IV-26的異構物，在腦腫瘤的形成上可能扮演一個很重要的角色。
目前雖然有Hdyn IV相關的研究發表，但其真正的功能仍不清楚。
文獻指出dynamin family間各蛋白質因結構的不同其功能也不盡相同，而Hdyn IV與其它dynamin family間主要的不同在於C端結構的不同，此是否意味著Hdyn IV與其它dynamin family的功能也不盡相同。為了瞭解Hdyn IV的轉錄是如何受到調控的，由Hdyn IV起動子的分析，更進一步釐清Hdyn IV真正的功能。
首先利用5’ RACE的方法找到轉錄起始點（+1）的位置，並從起動子的序列預測分析顯示：Hdyn IV的起動子序列含有 AP2和Sp1等轉錄因子的結合位置，但是缺乏TATA box和CAAT box。從HdynIV建構起動子對轉染HeLa細胞的功能性分析顯示：Hdyn IV的起動子應位於–140~+29的區域。更進一步進行DNA的片段序列刪除實驗，也證明Hdyn IV之轉錄要素應位於核苷酸序列–110 ~–100的區域。Electorphoretic mobility shift assay也顯示在–119 至–90 片段有一個專一性蛋白的結合。為了定出Hdyn IV轉錄要素真正的區域，我們由點突變實驗分析，配合活性分析之結果顯示：’’CTCCCAGCA’’（–108~–100序列）九個核苷酸序列對於Hdyn IV轉錄要素的轉錄活性是有相當影響的。

We first identified the transcriptional regulatory element of the human dynamin IV gene (Hdyn IV; dymple). The Hdyn IV belongs to a large GTPase family. This protein has a N-terminal highly conserved tripartite GTP-binding domain, coiled-coil (CC) region, but it lacks the pleckstrin homology (PH) domain and a modestly conserved C-terminal proline rich domain (PRD).
Hdyn IV gene is enriched in subcellular membrane fractions of cytoplasmic vesicles and endoplasmic reticulum, and the function of Hdyn IV gene is considered to be associated with the functions of mitochondria. The Hdyn IV is expressed as four alternative splicing variants in all eukaryotic organisms. Our question concerning why expressions of four alternative splicing variants in brain tumor tissues?
To elucidate the regulatory mechanism and the transcription factors involved, we firstly determined the transcriptional start site by 5’ RACE. We next cloned the 5’-flanking region of the Hdyn IV gene and determined the nucleotide sequence of 999 bases upstream from the transcription start site. The promoter has several potential binding sites for AP2, Sp1 binding protein, but it lacks TATA and CAAT boxes. Transfection studies using a series of Hdyn IV promoter luciferase constructs in HeLa cell demonstrate that the 5’flanking region has a promoter activity. Functional promoter element of the Hdyn IV gene was located within the –140~ +29 region. Deletion analyses demonstrated that the minimal promoter activity for the transcriptional element of Hdyn IV was detected in the sequence between nucleotides –110 and –100. Electorphoretic mobility shift assay demonstrated that a putative transcriptional factor bound to the –119 to –90 region. Site-directed mutagenesis analysis of this region revealed that nucleotides at positions –108 to –100 were essential for transactivation mediated by this element.
To summary, the data indicated that the ’’CTCCCAGCA’’ (-108~ -100) sequence is capable of regulating Hdyn IV gene expression. However, the protein involved in the binding of this novel sequence requires further study.

中文摘要………………………………………….1
英文摘要………………………………………….3
前言……………………………………………….5
材料與方法………………………………………10
結果………………………………………………24
討論………………………………………………28
參考文獻…………………………………………32
圖表………………………………………………36

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