Molecular characterization of soybean ribosomal protein S13 targeted to the nucleus

We isolated the full-length genomic clone of STLI25 encoding RPS13 (ribosomal protein S13) in soybean. Genomic DNA structure of SLTI25 is similar to that of Arabidopsis ribosomal protein S13. RNA expression of SLTI25 was induced by salt, ABA, or wounding stress, but reduced by dehydration stress. To determine the subcellular localization of the gene product fused to GFP, we were able to confirm that SLTI25-GFP was restricted to the nucleus. By domain swapping analysis, it was shown that C-terminal region of SLTI25 with a putative nucleus localization signal was necessary and sufficient for nucleus targeting of the fusion protein in plants. This new findings provide an evidence that SLTI25 is targeted to the nucleus for the ribosome subunit assembly in plants.