The Role of Non-Coding RNAs in Controlling Mammalian RNA Polymerase II Transcription
Stacey D. Wagner, Jennifer F. Kugel and James A. Goodrich
from: RNA and the Regulation of Gene Expression: A Hidden Layer of Complexity (Edited by: Kevin V. Morris). Caister Academic Press, U.K. (2008)
Controlling transcription of protein-encoding genes into mRNA is central to all basic biological processes and understanding mechanisms of transcriptional control has been the focus of intense investigation. In the case of mammalian protein-encoding genes, a multitude of protein factors that regulate mRNA transcription have been discovered and characterized over the past four decades. During that time a few RNAs were found to play a role in transcriptional regulation in very specific biological situations. Only recently has the scientific community begun to appreciate that RNAs play a much larger part in regulating mammalian transcription. This appreciation grew out of the discoveries of a number of RNA transcriptional regulators, some of which have the potential to control entire transcriptional programs in response to extracellular stimuli. At the same time, studies have shown that a much larger portion of the genome is transcribed than previously thought, and that many of the transcripts produced in mammalian cells do not encode protein, and hence are called non-coding RNAs (ncRNA). With increased awareness of the regulatory potential of ncRNAs, researchers have begun specifically looking for ncRNA transcriptional regulators. This search will likely result in a dramatic increase in the number and complexity of these novel transcriptional regulators over the next few years. Here, we review ncRNAs that control mammalian mRNA transcription. The ncRNAs discussed are grouped by the specific stage of transcription that they target. Intriguingly, most stages of the reaction are now known to be targeted by at least one ncRNA, from the mobilization of activators through the termination of transcription. Throughout the chapter we also include our thoughts on the pressing questions that could next be addressed to further our understanding of each of the ncRNAs read more ...