We have constructed recombinant DNA clones containing small complementary DNA (cDNA) sequences homologous to portions of a 4.8-kb yeast viral double-stranded RNA (dsRNA) (L1) that codes for the viral capsid polypeptide. Neither the viral dsRNA nor its in vitro transcript is polyadenylated; hence the cDNAs were synthesized by reverse transcriptase on the in vitro mRNA transcript made by the viral transcriptase, using sheared salmon sperm DNA as a random primer. This is the first reported cloning of cDNA homologous to a viral double-stranded RNA. This method should be of general utility for dsRNA viruses, since all have a capsid-associated transcriptase activity. The lengths of the overlapping cDNA inserts varied from 100 to 800 bp. About 40% of them mapped to the 5' end of the in vitro transcript, and these have been ordered. At least 1485 bp of this end of L1 is represented in the cloned cDNAs characterized. Using the cloned cDNAs as probes, we have shown that the L dsRNAs of two viral subtypes are similar at the transcription initiation site and dissimilar elsewhere.
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http://dx.doi.org/10.1016/0378-1119(82)90010-5 | DOI Listing |
Virol J
January 2025
Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
Background: Vibrio parahaemolyticus is a marine bacterium causing seafood-associated gastrointestinal illness in humans and acute hepatopancreatic necrosis disease (AHPND) in shrimp. Bacteriophages have emerged as promising biocontrol agents against V. parahaemolyticus.
View Article and Find Full Text PDFPlant Dis
January 2025
Guizhou University, Jiaxiu South Street, Huaxi District, Guiyang, China, 550025;
Passion fruit (Passiflora edulis) is a commercially important crop known for its nutritional value, high antioxidant content, and use in beverages and desserts. Gulupa baciliform virus A (GBVA), tentatively named Badnavirus in the family Caulimoviridae, is a cryptic circular double-stranded DNA (dsDNA, ≈6,951 bps) virus recently reported in Colombia with asymptomatic infection of passion fruit (Sepúlveda et al. 2022).
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Physiology and Biophysics, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, United States.
The Rep68 protein from Adeno-Associated Virus (AAV) is a multifunctional SF3 helicase that performs most of the DNA transactions necessary for the viral life cycle. During AAV DNA replication, Rep68 assembles at the origin of replication, catalyzing the DNA melting and nicking reactions during the hairpin rolling replication process to complete the second-strand synthesis of the AAV genome. We report the cryo-electron microscopy structures of Rep68 bound to the adeno-associated virus integration site 1 in different nucleotide-bound states.
View Article and Find Full Text PDFBMC Gastroenterol
January 2025
Department of Pediatrics, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710061, China.
Background: The increased apoptosis of bile duct epithelial cells (BECs) due to some damage factors is considered the initiating factor in the occurrence and progression of biliary atresia (BA). Vitamin D receptor (VDR) is thought to play a crucial role in maintaining the intrinsic immune balance and integrity of bile duct epithelial cells (BECs). To investigate the role of VDRs in the pathogenesis and progression of BA using in vitro and in vivo models.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Single-Molecule and Cell Mechanobiology Laboratory, Daejeon, 34141, South Korea.
Helicase is a nucleic acid motor that catalyses the unwinding of double-stranded (ds) RNA and DNA via ATP hydrolysis. Helicases can act either as a nucleic acid motor that unwinds its ds substrates or as a chaperone that alters the stability of its substrates, but the two activities have not yet been reported to act simultaneously. Here, we used single-molecule techniques to unravel the synergistic coordination of helicase and chaperone activities, and found that the severe acute respiratory syndrome coronavirus helicase (nsp13) is capable of two modes of action: (i) binding of nsp13 in tandem with the fork junction of the substrate mechanically unwinds the substrate by an ATP-driven synchronous power stroke; and (ii) free nsp13, which is not bound to the substrate but complexed with ADP in solution, destabilizes the substrate through collisions between transient binding and unbinding events with unprecedented melting capability.
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