The micro and macro of RNA function

The central dogma uniquely positions RNA as the key molecular player for translating genetic software into protein hardware. But it has become increasingly clear that RNA also plays an essential regulatory role within cells. MicroRNAs in particular have emerged as ubiquitous and still poorly understood molecules involved in the control of a wide variety of biological processes. RNA has also recently been shown to have important roles in structural assembly within cells. A diverse set of speakers at the Minisymposium on Micro-and Coding RNA highlighted some of these new and often unexpected roles of RNA across a range of length scales. her lab's work on cotranscriptional mRNA splicing. Her talk underscored the importance of ATP-dependent RNA helicases in rearranging RNA secondary structure and the integral role for chromatin modification in coordinating RNA rearrangements with transcription in space and time. Albert Rosana (Owttrim lab, University of Alberta) also discussed RNA helicases within the fascinating context of temperature fluctuations of cyanobacteria. He described his work on the altered expression of the oligomeric RNA helicase CrhR as a temperature stress response. His work provides new insights into RNA regulation , suggesting CrhR autoregulates its expression through a combination of RNA processing and RNA–protein stabilization mechanisms , which in turn leads to temperature-dependent regulation of small regulatory RNAs. Several presentations explored how RNAs play a role in the assembly of large-scale intracellular structures. discussed her work on RNAs in the assembly of the mitotic spindle. She utilized Xenopus egg extracts and next-generation sequencing approaches to demonstrate a surprising role for splicing factors in mitosis. This suggests the intriguing possibility that RNA processing plays a regulatory role in cell division. Moving to even larger scales, Cliff Brangwynne (Princeton University) discussed his lab's work on the biophysics of ribonucleo-protein (RNP) bodies—large, non–membrane bound assemblies that behave as liquid-phase droplets of RNA and protein. This work exploits the nucleus of Xenopus oocytes to study the nucleolus, an RNP droplet involved in ribosome biogenesis. The presentation revealed some unexpected biophysical consequences of the large length scales involved, with important implications for nuclear RNP organization and function. The nucleolus was also the central theme of a talk by Thoru Pederson (University of Massachusetts Medical School), who summarized his lab's recently published work on a subset of microRNAs localized in the nucleolus of rat myoblasts. He also reported new results on the nucleolar presence of certain mRNAs in these cells, …