2017年2月15日， 國際核酸類重要學術期刊《Nucleic Acids Research》雜誌線上發表了北京大學化學與分子工程學院趙美萍研究組的一篇研究論文， 論文題為：A branch-migration based fluorescent probe for straightforward, sensitive and specific discrimination of DNA mutations。 研究發明了一種新型探針：鏈遷移探針。 華中科技大學計劃生育研究所肖先金副教授為論文第一作者。
核酸探針在低豐度基因點突變的檢測中有著廣泛的應用， 開發常溫、快速的探針檢測體系對構建高通量基因晶片和實現即時檢測(Point of care analysis)有著重要的意義。 但傳統的核酸探針無法在常溫下實現對突變型DNA和野生型DNA的高效區分， 必須要精心優化探針的序列和調控檢測的溫度，
在鏈遷移過程中， 探針與突變鏈的自由能變化為0， 與野生型DNA在鏈遷移區域存在單堿基錯配， 其自由能變化大於0(ΔG2>0)， 根據轉化率與自由能變化的關係， 鏈遷移探針可以在常溫下有效地區分野生型DNA和突變型DNA。 對於低豐度突變型DNA的檢測， 其靈敏度可達0.3%-1%， 檢測時間僅為3分鐘， 並且適用于高GC含量的目標序列。 在低豐度基因突變的即時檢測、高通量體外檢測中有著廣泛的應用前景。 肖先金副教授在新型核酸探針的構建及其在生物醫學中的應用方面有著豐富的研究經驗， 他參與的另一個專案發明了穿膜肽與DNA的新型連接方式， 構建了CPP-DNA探針， 實現了細胞內核酸酶的高靈敏、特異性成像。
原文連結：
A branch-migration based fluorescent probe for straightforward, sensitive and specific discrimination of DNAmutations
原文摘要：
geneticmutations are important biomarkers for cancer diagnostics and surveillance. Preferably, the methods for mutation detection should be straightforward, highly specific and sensitive to low-level mutations within various sequence contexts, fast and applicable at room-temperature. Though some of the currently available methods have shown very encouraging results, their discrimination efficiency is still very low. Herein, we demonstrate a branch-migration based fluorescent probe (BM probe) which is able to identify the presence of known or unknown single-base variations at abundances down to 0.3%-1% within 5 min, even in highly GC-rich sequence regions. The discrimination factors between the perfect-match target and single-base mismatched target are determined to be 89–311 by measurement of their respective branch-migration products via polymerase elongation reactions. The BM probe not only enabled sensitive detection of two types of EGFR-associated point mutations located in GC-rich regions, but also successfully identified the BRAF V600E mutation in the serum from a thyroid cancer patient which could not be detected by the conventional sequencing method. The new method would be an ideal choice for high-throughput in vitro diagnostics and precise clinical treatment.
作者：趙美萍 點擊：次