Quality evaluation of a polyclonal antibody against endogenous TDP-MP20. (A) Schematic representation of MP20 antibody (MP20 Ab) recognizing a unique C-terminal peptide sequence of MP20. (B) Immunocytochemistry results showing FLAG-MP20 overexpression in HeLaS3 cells. MP20 Ab (green), FLAG (magenta), and Hoechst (blue). Scale bar: 20 μm. (C) Immunocytochemistry showing MP20-endo staining in HeLaS3 cells, using a peptide-absorbed MP20 Ab (green) and Hoechst (blue). MP18 peptide served as a negative control. Scale bar: 20 μm. (D) IP analysis of FLAG-MP20–overexpressing HEK293T cells using FLAG or MP20 Ab. An anti-IgG Ab was used as a negative control. Endogenous TDP-43 SVs (SVs-endo) include cleaved FL-endo and variants derived from short isoforms. (E) RT-PCR results comparing TARDBP splicing patterns in human cell lines (HEK293T and SH-SY5Y), adult mouse (11 mo old, male) brain cortex, and spinal cord. (F) WB analysis of MP20 expression in adult mouse (22 mo old, male) brain cortex and spinal cord. (G) Fluorescent immunostaining of adult mouse (22 mo old, male) brain cortex, stained with MP20 (green), MAP2 (magenta), and Hoechst (blue). Arrowheads and arrows denote MAP2-positive and MAP2-negative cells, respectively. Scale bar: 50 μm (upper panel), 10 μm (lower panel). Source data are available for this figure: SourceData F4.