RNA-protein interactions — RNA helicases
DEAD-box RNA helicases are a large group (>20 in the family) of ATP-dependent enzymes that can unwind RNA duplexes. These helicases have been functionally implicated in nearly every step of RNA metabolism, from transcription and splicing, to translation and RNA degradation. In collaboration with the Wysocka lab at Stanford, we uncovered DDX21 as a central regulator of ribosomal biogenesis in both the nucleolus and nucleoplasm. DDX21 acts to enhance Pol I transcription and subsequently controls post-transcriptional methylation of the ribosomal RNA. Additionally, it positively regulates Pol II transcription at ribosomal protein genes via the 7SK snRNA as a P-TEFb release factor. What regulates the localization and activity of DDX21 remains an active area of research.
Exploration of additional DEAD-box proteins, and related RNA helicases, will provide key insights into the basic RNA-centric pathways. Efforts to understand which RNAs are targeted, the functional role for specific helicases, and the post-translational regulation of helicase are actively being pursued.