La interacts directly with miR-122 through LaM and RRM1. (A) Sequences for miR-122 and miR-190. (B) EMSAs with purified La^1–408 and 5′ fluorescently labeled miR-122 or miR-190. La^1–408 was titrated from 244 pM to 2 µM. The migration of each miRNA was detected by in-gel fluorescence. The fraction bound was quantified as a function of the exhaustion of free miRNA. (C) Schematic illustrating the four functional domains of La. (D) EMSAs with 5′ fluorescently labeled miR-122 and purified La^1–334, La^1–224, or La^1–103. The titration range of each La truncation is indicated above each gel. miR-122 migration was detected by in-gel fluorescence. The fraction bound was quantified as a function of the exhaustion of free miR-122. (E) Quantification of Fig. 6 D showing the calculated K_d values. (F) EMSAs with 5′ fluorescently labeled miR-122 and purified La^104–408, La^225–408, or La^335–408. Each La truncation was titrated from 244 pM to 2 µM. miR-122 migration was detected by in-gel fluorescence. Source data are available for this figure: SourceData F6.