Supplemental Data

Files in this Data Supplement:

• Supplemental Figure 1 - T-DNA tagging and mRNA expression of the MRPL11 gene. (A) The mrpl11-1 mutation is due to a T-DNA insertion in the 3’-UTR MRPL11 gene. The insertion is not drawn to scale. LB, left border; RB, right border. (B) Detection of MRPL11 transcripts in mutant and WT plants. Forty-microgram samples of total RNA were analyzed using as probe a fragment of MRPL11 cDNA. To control for RNA loading, the blot was reprobed with a cDNA fragment derived from the ACTIN1 gene.
• Supplemental Figure 2 - Protein sequence comparison of L11 subunit of ribosomes (RPL11) in organelles of higher plants and in prokaryotes. The amino acid sequence of the Arabidopsis mitochondrial RPL11 protein (MRPL11, gi: 7270500) was compared with that of the Arabidopsis plastid RPL11 (PRPL11, gi: 6910575) and Spinach (PRPL11, gi: 21313) and with RPL11 protein sequences from Synechocystis (gi: 1652498), B. subtilis (gi: 2632369) and E. coli (gi: 2367334). Chloroplast or mitochondrial transit peptides predicted by TargetP are indicated by italic letters. Black boxes indicate strictly conserved amino acids, shaded boxes closely related amino acids. The symbol ´+´ refers to amino acid residues involved in the binding of the antibiotic microccin; circles highlight lysine residues that are modified by ε-N-trimethylation.
• Supplemental Figure 3 - In vitro dual-import of MRPL11 and PRPL11. The precursor proteins of MRPL11 (A) and PRPL11 (B) were incubated with spinach leaf mitochondria and chloroplasts together. 15 μg/ml Proteinase K were added after import where indicated. Mitochondria and chloroplasts were re-isolated on a 4% percoll gradient after the import. as described in the Materials section. Lane: 1, precursor protein alone; Lane: 2, mitochondrial fraction; Lane: 3, as lane 2 except that the import reaction was treated with Proteinase K; Lane: 4, chloroplast fraction; Lane: 5, as lane 4 except that the import reaction was treated with Proteinase K. The prefixes “pre” and “mat” designate the precursor and mature forms of the corresponding protein, respectively. Note that the predicted MRPL11 transit peptide is rather short (13 amino acid residues based on TargetP prediction). As a consequence, the difference between the precursor and mature form of the protein could not be displayed by the adopted PAGE system.