FIGURE 8.

XlCAF1 required the 7-methyl GpppG cap for translational repression but not deadenylation. A, the relative translation of firefly luciferase activity in response to each protein is shown. The luciferase mRNAs used contained a ApppG cap (top) or a 7-methyl GpppG cap and stem-loop in the 5′-UTR (middle) or a ApppG cap and a CSFV IRES in the 5′ UTR (bottom). The ApppG and stem-loop reporters contained a poly(A) tail of 39 adenosines. The IRES reporter does not contain a poly(A) tail. Normalization and error bars were determined as for Fig. 1B. Bottom panel, lysates equivalent to two oocytes were loaded in each lane and analyzed by Western blotting with α-HA-11 and α-actin. B, poly(A) status of reporter RNA with an ApppG cap. Lanes 1 and 3 show the ³²P RNA without a poly(A) before and after injection into oocytes, respectively. Lanes 2 and 4 show the ³²P RNA with a poly(A) tail before and after injection into oocytes, respectively. Lanes 5–10 indicate poly(A) tail length of the ³²P RNA when tethered to the indicated MS2 fusion protein.