Figure 10.

Working Model for the Posttranscriptional Control of psbD Gene Expression.

The sequence of the psbD 5′UTR from Chlamydomonas is given with the PRB2 site, the U-rich translational element boxed in gray, and the putative Shine-Dalgarno element (PRB1) (Nickelsen et al., 1999). The AUG start codon (gray letters) is marked by Met. Putative additional components of the Nac2/RBP40 complex are indicated by a question mark. The closed arrow represents the change in RNA conformation induced by RBP40, and the open arrows stand for the subsequent binding of components of the translational machinery. For further explanation, see text.