Fig. 4.

Specific and direct interactions between (GGGGCC)₅ and/or (CCCCGG)₅ and hnRNP A1, hnRNP F, SFRS2, and ALYREF but not hnRNP K or Magoh (negative control). Magoh, SRSF2 9-101, ALYREF, hnRNP A1-like2, hnRNP K, and hnRNP F were expressed in E. coli and purified (see Supplementary Table 4). (GGGGCC)₅ (sense) and (CCCCGG)₅ (antisense) RNA oligonucleotides were end labelled with polynucleotide kinase using [ɣ-32P]-ATP, prior to incubation with purified proteins. RNA was covalently bound (+) or not (−) following UV irradiation. The absence of radioactive signal (right panel, PhosphoImage) in the absence of UV irradiation demonstrates specificity of direct binding observed after UV treatment. All gels shown in the different panels were exposed simultaneously for the same amount of time (4 h). Note that a high molecular weight band is also observed for ALYREF due to oligomerisation properties [10]