The nuclear basket is required for perinuclear scanning. (A) Cartoon illustrating the phenotype of mlp1/2 deletion leading to basketless pores. (B) Live cell RNA imaging of GAL1pro-24PP7-GLT1 mRNA shows reduced residence time at the nuclear periphery. Individual frames from a video acquired in 37-ms intervals. Lower right panel shows all nuclear positions of a single RNA superimposed onto a single frame. Blue arrows show sites of transcription, and yellow and purple arrows show the tracked mRNA in individual frames and MAX projected image, respectively. (C) Characterization of perinuclear mRNA scanning for GAL1pro-24PP7-GLT1 mRNAs in WT Δmlp1/2 and Δnup60. Timescales of continuous mRNP scanning (left), jump distance at the periphery (middle), and timescales of restricted movements (right) are shown. 156 (WT), 105 (ΔMLP1/2), and 76 (ΔNUP60) tracks were analyzed. See text for details. P < 0.05, comparing WT versus mutants using a randomized ANOVA followed by posthoc tests.