The GC-rich sequence immediately downstream of the TDP- FL-stop in TARDBP is crucial for controlling sensitivity to hnRNP K. (A) Schematic representation of a mini-gene containing exon 6 (1–2,100) (Ex6) of TARDBP. Two potential hnRNP K consensus sites (K-1 and K-2) are described. Orange or blue lines show alternative donor (D) and acceptor (A) sites, and magenta lines indicate the stop codon of FL. (B) RT-PCR images of the effect of hnRNP K on splicing of the mini-gene (Ex6) with deletion of the potential hnRNP K consensus sequence in HEK293T cells. (C and E) Schematic representation of systematic deletion mutants of the TARDBP mini-gene (Ex6). Green box indicates polypyrimidine tract (PPT). A dotted square in E indicates 485–584 residues in exon 6, annotated with FL-stop (magenta), GU-rich (light blue), and AU-rich (purple) residues, respectively. (D and F) RT-PCR images of HEK293T cells coexpressing the TARDBP mini-genes (Ex6) with or without hnRNP K. Source data are available for this figure: SourceData FS4.