RNA-dependent RNA polymerase (RdRp) was solubilized and purified from cellular membranes isolated from alfalfa mosaic virus (AIMV)-infected tobacco by employing a procedure recently described for brome mosaic virus RdRp [R. Quadt and E.M.J. Jaspars, 1990, Virology 178, 189-194]. The purified AIMV RdRp is completely dependent on added template RNAs and exhibits a high degree of template specificity. Analysis of the protein composition of AIMV RdRp showed that AIMV-encoded proteins P1 and P2 and the coat protein (CP) are present in the active enzyme complex. Minus-strand synthesis by the AIMV RdRp is inhibited by AIMV CP. Native double-stranded AIMV RNAs are utilized as template for viral RNA synthesis by AIMV RdRp indicating that a helicase activity is present in the purified AIMV RdRp preparation.
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http://dx.doi.org/10.1016/0042-6822(91)90674-z | DOI Listing |
Virology
July 1997
Department of Agricultural Chemistry, Oregon State University, Corvallis 97331-7301, USA.
An RNA-dependent RNA polymerase (RdRp) activity was detergent-solubilized from the chloroplast membranes of Chinese cabbage leaves infected with turnip yellow mosaic virus (TYMV). The template-dependent, micrococcal nuclease-treated activity synthesized full-length minus strands from TYMV RNA and 3'-fragments as short as a 28-nucleotide-long RNA comprising the amino acid acceptor stem of the 3'-tRNA-like structure (TLS). Minus strands were shown to arise by de novo initiation with the insertion of GTP opposite the penultimate (C) residue of the 3'-terminal -CCA.
View Article and Find Full Text PDFVirology
November 1995
Institute of Molecular Plant Sciences, Gorlaeus Laboratories, Leiden University, The Netherlands.
In the life cycle of a (+)-strand RNA plant virus the processes of template RNA recognition and initiation of the synthesis of a complementary strand by the viral RNA-dependent RNA polymerase (RdRp) are crucial early steps. Using a template-dependent in vitro RNA synthesizing system of alfalfa mosaic virus (AIMV) we were able to study the effect of small chemical modifications of the 3' end of the template RNAs on product formation. After oxidation of the 3'-terminal nucleoside of the template no products could be detected.
View Article and Find Full Text PDFVirology
May 1991
Department of Biochemistry, Gorlaeus Laboratories, Leiden University, The Netherlands.
RNA-dependent RNA polymerase (RdRp) was solubilized and purified from cellular membranes isolated from alfalfa mosaic virus (AIMV)-infected tobacco by employing a procedure recently described for brome mosaic virus RdRp [R. Quadt and E.M.
View Article and Find Full Text PDFFEBS Lett
January 1991
Department of Biochemistry, Gorlaeus Laboratories, Leiden University, The Netherlands.
The necessity of coat protein for infection of plants by alfalfa mosaic virus (AIMV) and other ilarviruses distinguishes this virus group from other plant virus groups. Recently, the presence of both a zinc-finger type motif and zinc in AIMV coat protein was described [(1989) Virology 168, 48-56]. We studied the effect of a zinc chelator on viral RNA synthesis.
View Article and Find Full Text PDFVirology
June 1990
Department of Biochemistry, Leiden University, The Netherlands.
A DNA copy of alfalfa mosaic virus (AIMV) RNA3 was transcribed in vitro in two different orientations with T7 RNA polymerase and the transcripts were used as templates for a virus-specific RNA-dependent RNA polymerase (RdRp) purified from AIMV-infected bean plants. Minus-stranded templates were transcribed by the RdRp into subgenomic plus-stranded RNA4. A deletion analysis showed that a sequence in minus-strand RNA3, located between nucleotides -8 and -55 upstream of the initiation site for RNA4 synthesis, was sufficient for subgenomic promoter activity in vitro.
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