利用阿斯匹林來啟動被感染宿主內(nèi)細菌基因的表達，研究人員發(fā)現(xiàn)了一種研究宿主與致病原間相互作用的安全又容易的新方法,，研究成果在線發(fā)表在10月出版的《自然—方法學》期刊上,。
當某種細菌感染了宿主的某一器官時，這種細菌會表達出一系列不同的基因,。這些基因在不同的時間被表達出來,，因此對微生物具有不同的毒性。但是，因為在嚴格受控的動物試驗中缺乏安全的選擇性調(diào)控細菌基因的表達,，所以,，對細菌基因表達過程的研究受到了阻礙。
Eduardo Santero和同事報告說,，一種與乙酰水楊酸即阿斯匹林相呼應的受控基因表達回路可以被整合進細菌中,，用于控制特定基因的表達。為了從原理上證明新方法的有效性,，他們對一種沙門氏菌實施基因工程改造,，讓它表達出一種能將無毒化學物質(zhì)轉(zhuǎn)化為有毒物質(zhì)的酶，然后,，再將這種轉(zhuǎn)基因細菌注射進小鼠體內(nèi),。他們發(fā)現(xiàn)，調(diào)控阿斯匹林能夠打開被沙門氏菌感染的細胞中的嵌入基因,，并殺死它們,。這種原理證明性試驗表明，新方法可廣泛應用于宿主—致病體間相互作用的研究,。（科學時報）
原始出處:
Nature Methods - 4, 937 - 942 (2007)
Published online: 7 October 2007; | doi:10.1038/nmeth1107
In vivo gene regulation in Salmonella spp. by a salicylate-dependent control circuit
José Luis Royo1, 2, 4, Pablo Daniel Becker2, 4, Eva María Camacho1, Angel Cebolla3, Claudia Link2, Eduardo Santero1 & Carlos Alberto Guzmán2
1 Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide–Consejo Superior de Investigaciones Científicas, Carretera, Utrera, Km 1, E-41013 Sevilla, Spain.
2 Department of Vaccinology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany.
3 Biomedal SL, Avda. Américo Vespucio 5, Blq E 1a planta, E-41092 Sevilla, Spain.
4 These authors contributed equally to this work.
Correspondence should be addressed to Eduardo Santero esansan@upo.es
Systems allowing tightly regulated expression of prokaryotic genes in vivo are important for performing functional studies of bacterial genes in host-pathogen interactions and establishing bacteria-based therapies. We integrated a regulatory control circuit activated by acetyl salicylic acid (ASA) in attenuated Salmonella enterica that carries an expression module with a gene of interest under control of the XylS2-dependent Pm promoter. This resulted in 20–150-fold induction ex vivo. The regulatory circuit was also efficiently induced by ASA when the bacteria resided in eukaryotic cells, both in vitro and in vivo. To validate the circuit, we administered Salmonella spp., carrying an expression module encoding the 5-fluorocytosine–converting enzyme cytosine deaminase in the bacterial chromosome or in a plasmid, to mice with tumors. Induction with ASA before 5-fluorocytosine administration resulted in a significant reduction of tumor growth. These results demonstrate the usefulness of the regulatory control circuit to selectively switch on gene expression during bacterial infection.
