Alternative splicing (AS) regulator that binds to specific mRNAs and modulates auxin effects on the transcriptome. Displaced from its targets upon binding to AS competitor long non-coding RNA (ASCO-RNA). Relocalizes to cytoplasmic bodies in trichoblast cells containing root hairs or when coexpressed with Medicago enod40 RNA. Expressed in root meristems, lateral root primordia and root vascular tissues. Constitutively expressed. No visible phenotype. Nsra and nsrb double mutants are less sensitive to auxin. Truncated N-terminus.