Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

After microinjection of antibodies against RNA polymerase I into the nuclei of cultured rat kangaroo (PtK2) and rat (RVF-SMC) cells alterations in nucleolar structure and composition were observed. These were detected by electron microscopy and double-label immunofluorescence microscopy using antibodies to proteins representative of the three major components of the nucleolus. The microinjected antibodies produced a progressive loss of the material of the dense fibrillar component (DFC) from the nucleoli which, at 4 h after injection, were transformed into bodies with purely granular component (GC) structure with attached fibrillar centers (FCs). Concomitantly, numerous extranucleolar aggregates appeared in the nucleoplasm which morphologically resembled fragments of the DFC and contained a protein (fibrillarin) diagnostic for this nucleolar structure. These observations indicate that the topological distribution of the material constituting the DFC can be experimentally influenced in interphase cells, apparently by modulating the transcriptional activity of the rRNA genes. These effects are different from nucleolar lesions induced by inhibitory drugs such as actinomycin D-dependent "nucleolar segregation". The structural alterations induced by antibodies to RNA polymerase I resemble, however, the initial events of nucleolar disintegration during mitotic prophase.
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PMID:Nucleolar changes after microinjection of antibodies to RNA polymerase I into the nucleus of mammalian cells. 322 76

Rotaviruses (RVs) are segmented double-stranded RNA viruses that cause gastroenteritis in mammals and birds. Within the RV genus, eight species (RVA-RVH) have been proposed. Here, we report the first RVF and RVG sequences for the viral RNA polymerase (VP1)-encoding segments and compare them to those of other RV species. Phylogenetic analyses indicate that the VP1 RNA segments and proteins resolve into two major clades, with RVA, RVC, RVD and RVF in clade A, and RVB, RVG and RVH in clade B. Plus-strand RNA of clade A viruses, and not clade B viruses, contain a 3'-proximal UGUG cassette that serves as the VP1 recognition signal. VP1 structures for a representative of each RV species were predicted using homology modeling. Structural elements involved in interactions with the UGUG cassette were conserved among VP1 of clade A, suggesting a conserved mechanism of viral RNA recognition for these viruses.
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PMID:Rotavirus RNA polymerases resolve into two phylogenetically distinct classes that differ in their mechanism of template recognition. 2268 27