Figure 4.

MATR3 promotes exon 3 inclusion through its RRM domain. (a) Diagram of the primary structure of MATR3 and its mutants. Mutant ΔN lacks the first 397 amino acids at the N terminus; mutant ΔRRMs lacks both RRMs (amino acids 398–571 being deleted), mutant ΔRRM1 lacks RRM1 (amino acids 398–473 being deleted), ΔRRM2 lacks RRM2 (amino acids 496–571 being deleted), and ΔC lacks 129 amino acids at the C terminus (from 719 to 847). (b) Western blotting using anti-T7 antibody shows proper expression of all mutants. (c) The effects of MATR3 mutants on PDCD1 minigene exon 3 splicing were analysed in HEK293 cells; Quantitation of exon 3 inclusion from three independent experiments is shown in the histogram below. **P< 0.01, versus T7-empty vector (n = 3).