[RNA interference directed by small hairpin RNA expressed in COS-7 cells].
RNA interference is a phenomenon of gene silencing directed by double-stranded RNA. It can specifically inhibit gene expression by degrading mRNA efficiently and has been widely used to knockdown gene expression in Caenorhabditis elegans, Drosophila melanogaster, etc. For mammalian cells, dsRNA directed RNAi was detected only in murine undifferentiated ES or embryonic carcinoma (EC) cells. Our previous work proved the existence of RNAi effect for reporter gene GFP and endogenous gene Oct4 in undifferentiated murine ES cells. Yet in other kinds of mammalian cells, because of the existence of interferon pathway, long dsRNA will induce the cells to shutdown global protein translation and go to apoptosis. Therefore, dsRNA longer than 30 bp cannot be used to induce specific gene knockdown effect in these cells. Elbashir et al found that in vitro synthesized small interfering RNA (siRNA) (19-23 nt) could induce potent RNAi as effective as long dsRNA without showing unspecific effect, so that the interferon pathway could be bypassed. It was shown that during RNAi process, long dsRNA was first degraded into 19-23 nt siRNA and then recruited into RISC (RNA induced silencing complex) to degrade corresponding mRNA. However, the synthesis of siRNA is expensive and the effect is transient because the knockdown effect can only be maintained for about a week. Recently, it has been shown that U6 promoter directed small hairpin RNA (shRNA) can induce potent gene knockdown effect in murine P19 Embryonic Carcinoma cell. The RNAi effect of U6 promoter-driven shRNA corresponding to Green Fluorescence Protein (GFP) in COS-7 cells was checked. And it was found that the U6 promoter-driven shRNA for GFP can specifically and potently knockdown the GFP's expression in COS-7 cells. The result established the feasibility of using RNAi technique directed by U6 promoter-driven shRNA to study genes' function in COS-7 cell line.
Tang
Fu-Chou
FC
College of Life Sciences, Peking University, Beijing 100871, China.
Yang
Hong-Bo
HB
Meng
Guo-Liang
GL
Li
Cheng-Jian
CJ
Shang
Ke-Gang
KG
Zhang
Bo
B
Xue
You-Fang
YF
D000818:Animals; D019556:COS Cells; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic / Q000235:genetics; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012342:RNA, Small Nuclear / Q000235:genetics; D014162:Transfection
D008164:Luminescent Proteins; D012342:RNA, Small Nuclear; C405486:U6 small nuclear RNA; D049452:Green Fluorescent Proteins; D012313:RNA