Since Sbp1 coimmunoprecipitates with small nucleolar RNA 10 and 11 (Jong and Campbell 1986; Jong et al. 1987; Clark et al. 1990), to rule out possibilities of a change in mRNA translation due to changes of ribosome biogenesis by Sbp1 in the cell, we added purified Sbp1 into the WT cell extract and observed a similar inhibitory function of the translation of Pab1 mRNA by Sbp1 (Fig. 6B).