果蠅血管收縮素轉化酵素相關基因表現受tinman 基因直接調控

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2013-??-??

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國立臺灣師範大學生命科學學系
Department of Life Science, NTNU

Abstract

血管收縮素轉化酵素相關基因(Angiotensin converting enzyme related, acer)為哺乳類動物血管收縮素轉化酵素2 (Angiotensin converting enzyme 2, ACE2)在果蠅的同源基因,二者皆保有類似的酵素特性。為能進一步了解acer 基因在果蠅的功能,我們利用原位雜合解析其在胚胎發育時期的動態表現型態,實驗發現acer 信息核酸位於未受精的卵中,証實acer 為一母源基因,在胚胎發育初期acer 短暫消失無任何表現,在胚胎發育第十一期時acer 則表現在羊漿胚膜(aminoserosa)及未來形成心臟先驅細胞的背部中胚層,到胚胎發育第十四期時acer 持續表現於羊漿胚膜細胞並開始出現在心臟先驅細胞中,在胚胎發育晚期acer 則僅在心肌細胞中表現,另由報導基因研究發現,調控acer 在心臟細胞表現的加強子(enhancer)位於5’端到第二內插子約1.4 kb 的DNA片段中,此一加強子驅動報導基因表現可受tinman (tin)的表現而表現,突變加強子則不受影響,另由染色體免疫沈澱實驗,我們發現tin 蛋白可結合在加強子上,基於上述結果我們認為tin 可直接調控acer 的表現。
Angiotensin converting enzyme-related (acer) is a Drosophila homolog of mammalian angiotensin converting enzyme 2 (ACE2). Both ACER and ACE2 exhibit similar enzymatic activity. To better understanding the developmental function of acer in Drosophila, we have characterized the dynamic expression patterns of acer during embryogenesis. We find that acer is a maternal gene as its mRNA can be detected in fresh laid eggs. During early embryogenesis, the expression of acer is absent. The expression of acer is re-appeared in aminoserosa and the dorsal mesoderm at stage 11. At stage 14, acer mRNA is restricted in aminoserosa and cardial precursors. The expression of acer is maintained in cardial cells during late embryogenesis. Additionally, we have characterized a 1.5 kb DNA fragment that confers the cardial-specific expression pattern of acer. The enhancer activity can be modulated by the expression of tinman. Additionally, tin protein can bind to the enhancer in vivo. Based on the above observations, we conclude that tin regulates the expression of acer directly.

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