Alternative splicing of anciently exonized 5S rRNA regulates plant transcription factor TFIIIA

Characterization of the EI mRNA isoform of TFIIIA. (A) In vitro translation of Arabidopsis EI mRNA. Lanes (1–6) 0, 0.5, 1, 2, 4, and 8 μg EI mRNA, respectively, added in a cell-free wheat germ extract. (B) In vivo translation of EI. Western blot using anti-HA antibody (top) and SDS-PAGE analysis (bottom) of the overexpression lines using L5-cDNA (left) and EI-cDNA (right) fused with HA-tag. Electrophoretic mobility shift assay using GST-LeTFIIIA(zf1-9) (C) and GST-LeTFIIIA(zf1-2) (D). 5S DNA was titrated with increasing concentrations of GST-LeTFIIIA(zf1-9) (lanes 1–9: 0, 0.2, 0.4, 0.9, 1.8, 3.5, 7, 14, and 28 nM, respectively) or GST-LeTFIIIA(zf1-2) (lanes 1–8: 0, 14, 28, 55, 110, 220, 440, and 880 nM, respectively).