Involved in pre-mRNA splicing and its phosphorylated form (by SRPK2) is required for spliceosomal B complex formation (PubMed:18425142). Independently of its spliceosome formation function, required for the suppression of incorrect R-loops formed during transcription; R-loops are composed of a DNA:RNA hybrid and the associated non-template single-stranded DNA (PubMed:28076779). . This is the function of Ensembl gene identifier ENSG00000174243 (DDX23, DEAD-box helicase 23).