Gel-shift assays performed with increasing concentration of purified His-Rab1b alone (A) or in the presence of competitor RNA SL123, SL3abc, or control RNA (B), His-ARF5 alone (C) or in the presence of competitor RNA SL123, SL3abc, or control RNA (D). Probes are colored as shown in the legend. Band shift conducted for His-Rab1b and His-ARF5 with a control RNA (E), His-PCBP2 (F), and His-Ebp1 (G) using the indicated probes. The graphs represent the adjusted curves obtained from the quantifications of the retarded complex relative to the free probe (mean ± SD) from two independent assays for each probe. Gel images are representative examples of one assay. For competition experiments (B) and (D), the % of retarded probe relative to the lane without competitor RNA was measured in triplicated assays using a probe: competitor RNA ratio 1:200 for Rab1b and 1:500 for ARF5.