| In this review 1 shall concentrate on RNA helicase A ( Dhx 9 ) , DP 103 ( Ddx 20 ) , p 68 ( Ddx 5 ) and p 72 ( Ddx 17 ) , proteins for which there is a strong body of evidence showing that they play important roles in transcription , often as coactivators or corepressors through their interaction with key components of the transcriptional machinery , such as CREB binding protein , p 300 , RNA polymerase 2 and histone deacetylases . . ^^^ |