FIG 4.

The RAA8 gene encodes a 269-kDa protein that exhibits six predicted C-terminal OPR motifs. (a) Scheme of the primary structure of the Raa8 polypeptide and two truncated versions. In silico analyses predicted several low-complexity regions (Gly-rich, Pro-rich, Gln-rich, Ala-rich, and Ser-rich regions), RNA binding residues, a chloroplast transit peptide (cTP), and OPR motifs. Both F19 and 31O13-4 encode truncated proteins. (b) Six OPR motifs in Raa8 were predicted by MEME Suite (28). The alignment was visualized using ClustalX (30), with a default color scheme assigned for each residue that met the amino acid profile of the alignment at that position. The consensus sequence defined by MEME Suite is indicated at the bottom. Numbers in front of the OPR motifs indicate the positions of the first amino acids. Numbers behind the motifs represent the P values defined by MEME Suite, using characterized OPR proteins, such as Raa1 and Rat2.