摘要
RNAi是近两年发展起来的一种阻抑基因表达的新方法。它通过导入一段与内源基因同源的双链RNA序列(dsRNA) ,使内源mRNA降解 ,从而达到阻抑基因表达的目的。目前已在线虫、果蝇、臭虫、真菌及植物等生物中建立RNAi技术 ,用于研究某些特定基因或已知基因在特定发育时期的功能。对于难于获得突变体的基因或生物体 ,RNAi技术尤其有效。虽然果蝇心脏发育基因wingless和tinman在果蝇心脏发育的早期功能已经清楚 ,它们都与果蝇心脏前体细胞的形成有关 ,但它们在果蝇心脏发育的后期功能仍有待进一步研究。实验运用RNAi技术 ,分别将tinman和wingless的dsRNA注入果蝇的早期胚胎 ,得到了这两个基因的dsRNA干扰表型 ,与两个基因的突变体表型非常相似 ,都表现为果蝇心脏前体细胞不能形成或心脏管缺失。尤其是tinman基因的dsRNA ,还引起了肠中胚层缺失和体壁肌肉组织的紊乱 ,而wingless基因的dsRNA却只影响心脏的形成 ,而不影响肠中胚层 ,说明dsRNA干扰具有非常强的特异性 ,因而不失为研究果蝇心脏发育基因功能的有效方法。
RNAi is a recently developed method to block the activity of cellular genes by artificially providing sense and anti sense RNA corresponding to a target gene. By inducing rapid degradation of the corresponding endogenous mRNA and blocking new mRNA synthesis, RNAi leads to post transcriptional gene silencing. Now this phenomenon has been claimed to exist in C. elegans, Drosophila, buds, fungi and plants and is being used to study the functions of some special genes or the known genes at specific time point. It is extremely useful for those genes or organisms that their mutants are not easily obtained. The Drosophila heart related genes, tinman and wingless , have been shown to play an important role in coordinating the early formation of heart progenitor cells and precursors, yet the late function is still unexplored. In this exper iment, we took the advantage of RNAi technique, microinjected tinman and wingless dsRNA into the early embryos in Drosophila respectively and got these two genes' RNAi phenotypes, which were very similar to that of their mutant, showing heart tube defects or no heart precursors formation. tinman dsRNA even caused visceral mesoderm defects and the somatic muscles disruption, yet wingless dsRNA only affected heart precursors and had no effect on visceral mesoderm and somatic muscles, indicationg that the heart related genes dsRNA interference worked effectively and exclusively in Drosophila.
基金
国家留学基金
湖南师范大学特聘教授基金。~~
