Transcription (biology)

About: Transcription (biology) is a research topic. Over the lifetime, 56532 publications have been published within this topic receiving 2952782 citations. The topic is also known as: genetic transcription & transcription, genetic.

Structure of replicating SARS-CoV-2 polymerase.

Abstract: The new coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses an RNA-dependent RNA polymerase (RdRp) for the replication of its genome and the transcription of its genes1-3. Here we present a cryo-electron microscopy structure of the SARS-CoV-2 RdRp in an active form that mimics the replicating enzyme. The structure comprises the viral proteins non-structural protein 12 (nsp12), nsp8 and nsp7, and more than two turns of RNA template-product duplex. The active-site cleft of nsp12 binds to the first turn of RNA and mediates RdRp activity with conserved residues. Two copies of nsp8 bind to opposite sides of the cleft and position the second turn of RNA. Long helical extensions in nsp8 protrude along exiting RNA, forming positively charged 'sliding poles'. These sliding poles can account for the known processivity of RdRp that is required for replicating the long genome of coronaviruses3. Our results enable a detailed analysis of the inhibitory mechanisms that underlie the antiviral activity of substances such as remdesivir, a drug for the treatment of coronavirus disease 2019 (COVID-19)4.

Mammalian Sir2 homolog SIRT7 is an activator of RNA polymerase I transcription

Abstract: We investigated the role of SIRT7, one of the seven members of the mammalian sirtuin family. We show that SIRT7 is a widely expressed nucleolar protein that is associated with active rRNA genes (rDNA), where it interacts with RNA polymerase I (Pol I) as well as with histones. Overexpression of SIRT7 increases Pol I-mediated transcription, whereas knockdown of SIRT7 or inhibition of the catalytic activity results in decreased association of Pol I with rDNA and a reduction of Pol I transcription. Depletion of SIRT7 stops cell proliferation and triggers apoptosis. Our findings suggest that SIRT7 is a positive regulator of Pol I transcription and is required for cell viability in mammals.

The RNA polymerase II CTD coordinates transcription and RNA processing

Abstract: The C-terminal domain (CTD) of the RNA polymerase II largest subunit consists of multiple heptad repeats (consensus Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7), varying in number from 26 in yeast to 52 in vertebrates. The CTD functions to help couple transcription and processing of the nascent RNA and also plays roles in transcription elongation and termination. The CTD is subject to extensive post-translational modification, most notably phosphorylation, during the transcription cycle, which modulates its activities in the above processes. Therefore, understanding the nature of CTD modifications, including how they function and how they are regulated, is essential to understanding the mechanisms that control gene expression. While the significance of phosphorylation of Ser2 and Ser5 residues has been studied and appreciated for some time, several additional modifications have more recently been added to the CTD repertoire, and insight into their function has begun to emerge. Here, we review findings regarding modification and function of the CTD, highlighting the important role this unique domain plays in coordinating gene activity.