Fig. 3

The effect of GFP double-stranded RNA injection on the transient expression of GFP in zebrafish embryos. Single-cell or 16-cell zebrafish embryos were injected with the GFP expression vector, pEGFP-N1. The embryos were coinjected with either GFP double-stranded RNA or a control double-stranded RNA. Columns A and C show the same field of embryos by light microscopy as seen under fluorescence in columns B and D, respectively. Columns A and B show embryos injected at the single-cell stage while columns C and D show embryos injected at the 16-cell stage. Rows 1–3 are designated by treatment to the left as injected with the GFP expression vector alone (row 1), GFP expression vector with control double-stranded RNA (row 2), or GFP expression vector with GFP double-stranded RNA (row 3). The embryo shown in row 4 was injected at the single-cell stage with GFP and Zf-T double-stranded RNA. While the zebrafish yolk does show some autofluorescence at higher magnifications, it is not apparent at the magnification shown in columns A and B. The yolk fluorescence seen here is from the GFP expression vector and is specifically attenuated by double-stranded RNA to GFP. On the other hand double-stranded RNA targeted to Zf-T does not interfere with GFP expression and since this embryo shows the ntl phenotype, the presence of the GFP expression vector does not attenuate the function of the Zf-T double-stranded RNA.