The Sox2 transcription factor binds RNA

Certain transcription factors are proposed to form functional interactions with RNA to facilitate proper regulation of gene expression. Sox2, a transcription factor critical for maintenance of pluripotency and neurogenesis, has been found associated with several lncRNAs, although it is unknown whether these interactions are direct or via other proteins. Here we demonstrate that human Sox2 interacts directly with one of these lncRNAs with high affinity through its HMG DNA-binding domain in vitro. These interactions are primarily with double-stranded RNA in a non-sequence specific fashion, mediated by a similar but not identical interaction surface. We further determined that Sox2 directly binds RNA in mouse embryonic stem cells by UV-cross-linked immunoprecipitation of Sox2 and more than a thousand Sox2-RNA interactions in vivo were identified using fRIP-seq. Together, these data reveal that Sox2 employs a high-affinity/low-specificity paradigm for RNA binding in vitro and in vivo.