The TFR is dispensable for autoprocessing of the fusion precursors. A. Schematic diagram depicting truncation and replacement (N-Hec1) of TRF amino acid sequences in the GST-Flag-TFR-PRNL precursor. B. Autoprocessing of the resulting fusion precursors in transfected HEK293T cells. Post-nuclear cell lysates were prepared at 40 h post transfection and subjected to western blotting using monoclonal mouse anti-Flag or anti-HA primary antibodies and IR800 goat anti-mouse second antibody. Schematic diagrams of the full length fusion precursor and processing products are indicated at left. Molecular mass markers (kDa) are indicated at right.