Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Viroids and viroid-like satellite RNAs from plants, and the human hepatitis delta virus (HDV) RNA share some properties that include small size, circularity and replication through a rolling-circle mechanism. Replication occurs in different cell compartments (nucleus, chloroplast and membrane-associated cytoplasmatic vesicles) and has three steps: RNA polymerization, cleavage and ligation. The first step generates oligomeric RNAs that result from the reiterative transcription of the circular templates of one or both polarities, and is catalyzed by either the RNA-dependent RNA polymerase of the helper virus on which viroid-like satellite RNAs are functionally dependent, or by host DNA-dependent RNA polymerases that, remarkably, viroids and HDV redirect to transcribe RNA templates. Cleavage is mediated by host enzymes in certain viroids and viroid-like satellite RNAs, while in others and in HDV is mediated by cis-acting ribozymes of three classes. Ligation appears to be catalyzed mainly by host enzymes. Replication most likely also involves many other non-catalytic proteins of host origin and, in HDV, the single virus-encoded protein.
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PMID:Rolling-circle replication of viroids, viroid-like satellite RNAs and hepatitis delta virus: variations on a theme. 2135 83

The rhabdoviruses have a non-segmented single stranded negative-sense RNA genome. Their multiplication in a host cell requires three viral proteins in addition to the viral RNA genome. The nucleoprotein (N) tightly encapsidates the viral RNA, and the N-RNA complex serves as the template for both transcription and replication. The viral RNA-dependent RNA polymerase is a two subunit complex that consists of a large subunit, L, and a non-catalytic cofactor, the phosphoprotein, P. P also acts as a chaperone of nascent RNA-free N by forming a N(0)-P complex that prevents N from binding to cellular RNAs and from polymerizing in the absence of RNA. Here, we discuss the recent molecular and structural studies of individual components and multi-molecular complexes that are involved in the transcription/replication complex of these viruses with regard to their implication in viral transcription and replication.
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PMID:Structural insights into the rhabdovirus transcription/replication complex. 2196 63

After a decade of having been the standard of care (SOC) for the treatment of chronic HCV infection, PEGylated IFN (combined with ribavirin) is now at the verge of being complemented and then replaced by a combination of new DAAs and even some compounds interacting with host cell factors. Principal targets for the direct-acting antivirals (DAAs) are the protease NS3/4A, the protein NS5A, and the RNA-dependent RNA polymerase NS5B, which offers at least two target sites, the catalytic domain for nucleos(t)ides and several non-catalytic (allosteric) domains for the non-nucleoside type of NS5B inhibitors. Two PIs have already been approved, but many more NS3/4A, NS5A, and NS5B (up to 40!) inhibitors are in (pre)clinical development. The abundance of candidate anti-HCV drugs will, on the one hand, speed up their development but, on the other hand, complicate the choice of the most appropriate drug combination(s).
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PMID:The race for interferon-free HCV therapies: a snapshot by the spring of 2012. 2293 36