The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform

Dennis H. Bamford - One of the best experts on this subject based on the ideXlab platform.

  • Replicase activity of purified recombinant protein P2 of double‐stranded RNA bacteriophage φ6
    The EMBO Journal, 2000
    Co-Authors: Eugeny V. Makeyev, Dennis H. Bamford
    Abstract:

    In nature, synthesis of both minus- and plus-sense RNA strands of all the known Double-Stranded RNA viruses occurs in the interior of a large protein assembly referred to as the polymerase complex. In addition to other proteins, the complex contains a putative polymerase possessing characteristic sequence motifs. However, none of the previous studies has shown template-dependent RNA synthesis directly with an isolated putative polymerase protein. In this report, recombinant protein P2 of Double-Stranded RNA bacteriophage phi6 was purified and demonstrated in an in vitro enzymatic assay to act as the replicase. The enzyme efficiently utilizes phage-specific, positive-sense RNA substrates to produce Double-Stranded RNA molecules, which are formed by newly synthesized, full-length minus-strands base paired with the plus-strand templates. P2-catalyzed replication is also shown to be very effective with a broad range of heterologous single-stranded RNA templates. The importance and implications of these results are discussed.

  • replicase activity of purified recombinant protein p2 of double stranded RNA bacteriophage φ6
    The EMBO Journal, 2000
    Co-Authors: Eugeny V. Makeyev, Dennis H. Bamford
    Abstract:

    In nature, synthesis of both minus- and plus-sense RNA strands of all the known Double-Stranded RNA viruses occurs in the interior of a large protein assembly referred to as the polymerase complex. In addition to other proteins, the complex contains a putative polymerase possessing characteristic sequence motifs. However, none of the previous studies has shown template-dependent RNA synthesis directly with an isolated putative polymerase protein. In this report, recombinant protein P2 of Double-Stranded RNA bacteriophage phi6 was purified and demonstrated in an in vitro enzymatic assay to act as the replicase. The enzyme efficiently utilizes phage-specific, positive-sense RNA substrates to produce Double-Stranded RNA molecules, which are formed by newly synthesized, full-length minus-strands base paired with the plus-strand templates. P2-catalyzed replication is also shown to be very effective with a broad range of heterologous single-stranded RNA templates. The importance and implications of these results are discussed.

Brenda L. Bass - One of the best experts on this subject based on the ideXlab platform.

  • Double-Stranded RNA binding proteins and their substrates.
    Nucleic acids symposium series, 1995
    Co-Authors: Brenda L. Bass
    Abstract:

    Double-Stranded RNA (dsRNA) binding proteins (dsRBPs) pose unique questions in regard to how proteins interact with RNA. This article presents a general overview of these questions and also introduces specific dsRBPs that are studied by my laboratory.

  • preferential selection of adenosines for modification by double stranded RNA adenosine deaminase
    The EMBO Journal, 1994
    Co-Authors: Andrew G Polson, Brenda L. Bass
    Abstract:

    Abstract Double-Stranded RNA adenosine deaminase (dsRAD), previously called the Double-Stranded RNA (dsRNA) unwinding/modifying activity, modifies adenosines to inosines within dsRNA. We used ribonuclease U2 and a mutant of ribonuclease T1 to map the sites of modification in several RNA duplexes. We found that dsRAD had a 5' neighbor preference (A = U > C > G) but no apparent 3' neighbor preference. Further, the proximity of the strand termini affected whether an adenosine was modified. Most importantly, dsRAD exhibited selectivity, modifying a minimal number of adenosines in short dsRNAs. Our results suggest that the specific editing of glutamate receptor subunit B mRNA could be performed in vivo by dsRAD without the aid of specificity factors, and support the hypothesis that dsRAD is responsible for hypermutations in certain RNA viruses.

Eugeny V. Makeyev - One of the best experts on this subject based on the ideXlab platform.

  • Replicase activity of purified recombinant protein P2 of double‐stranded RNA bacteriophage φ6
    The EMBO Journal, 2000
    Co-Authors: Eugeny V. Makeyev, Dennis H. Bamford
    Abstract:

    In nature, synthesis of both minus- and plus-sense RNA strands of all the known Double-Stranded RNA viruses occurs in the interior of a large protein assembly referred to as the polymerase complex. In addition to other proteins, the complex contains a putative polymerase possessing characteristic sequence motifs. However, none of the previous studies has shown template-dependent RNA synthesis directly with an isolated putative polymerase protein. In this report, recombinant protein P2 of Double-Stranded RNA bacteriophage phi6 was purified and demonstrated in an in vitro enzymatic assay to act as the replicase. The enzyme efficiently utilizes phage-specific, positive-sense RNA substrates to produce Double-Stranded RNA molecules, which are formed by newly synthesized, full-length minus-strands base paired with the plus-strand templates. P2-catalyzed replication is also shown to be very effective with a broad range of heterologous single-stranded RNA templates. The importance and implications of these results are discussed.

  • replicase activity of purified recombinant protein p2 of double stranded RNA bacteriophage φ6
    The EMBO Journal, 2000
    Co-Authors: Eugeny V. Makeyev, Dennis H. Bamford
    Abstract:

    In nature, synthesis of both minus- and plus-sense RNA strands of all the known Double-Stranded RNA viruses occurs in the interior of a large protein assembly referred to as the polymerase complex. In addition to other proteins, the complex contains a putative polymerase possessing characteristic sequence motifs. However, none of the previous studies has shown template-dependent RNA synthesis directly with an isolated putative polymerase protein. In this report, recombinant protein P2 of Double-Stranded RNA bacteriophage phi6 was purified and demonstrated in an in vitro enzymatic assay to act as the replicase. The enzyme efficiently utilizes phage-specific, positive-sense RNA substrates to produce Double-Stranded RNA molecules, which are formed by newly synthesized, full-length minus-strands base paired with the plus-strand templates. P2-catalyzed replication is also shown to be very effective with a broad range of heterologous single-stranded RNA templates. The importance and implications of these results are discussed.

Maxine L. Linial - One of the best experts on this subject based on the ideXlab platform.

  • Modification of retroviral RNA by Double-Stranded RNA adenosine deaminase.
    Journal of virology, 1995
    Co-Authors: Adeline M. Hajjar, Maxine L. Linial
    Abstract:

    In this report, we describe a recombinant provirus generated during in vitro passage that contains a short region of adenosine-to-guanosine hypermutation. The hypermutated region is restricted to complementary sequences present in the recombinant provirus. We propose that a duplex was formed in the recombinant RNA prior to reverse transcription. This duplex was a substrate for Double-Stranded RNA adenosine deaminase, an activity found in all cells examined that deaminates A in Double-Stranded RNA, converting it to inosine, which is further converted to a guanosine by reverse transcription. It appears that cis viral sequences facilitated the A-->G transitions.

Bertram L. Jacobs - One of the best experts on this subject based on the ideXlab platform.

  • Nuclear factor-90 of activated T-cells: A Double-Stranded RNA-binding protein and substrate for the Double-Stranded RNA-dependent protein kinase, PKR.
    Biochemistry, 1999
    Co-Authors: Jeffrey Langland, Peter N. Kao, Bertram L. Jacobs
    Abstract:

    NFAT transcription factors play a central role in initiating T-cell activation through the induction of immediate-early T-cell specific genes including interleukin-2 (IL-2). NFAT transcription factors bind to a sequence in the IL-2 enhancer known as the antigen receptor response element 2 (ARRE-2). Multiple proteins exhibiting ARRE-2 binding activity have been isolated, including a heterodimer from stimulated T-cell nuclear extracts consisting of Mr = 90 000 (NF90) and Mr = 45 000 (NF45) subunits. The subunits of this heterodimer have been cloned, and NF90 was found to encode a protein containing two domains that are predicted to form motifs capable of binding to Double-Stranded RNA. Using in vitro translated polypeptides, we have demonstrated that NF90 specifically binds to Double-Stranded RNA. Furthermore, NF90 was phosphorylated in a Double-Stranded RNA-dependent manner likely by the interferon-induced, Double-Stranded RNA-dependent protein kinase, PKR. The NF90 protein was found to be expressed not only in T-cells, but also in nonimmune HeLa cells. In HeLa cells, the protein was almost exclusively localized to the ribosome salt wash fraction of cell lysates.

  • Characterization of viral Double-Stranded RNA-binding proteins.
    Methods (San Diego Calif.), 1998
    Co-Authors: Bertram L. Jacobs, Jeffrey Langland, Teresa Brandt
    Abstract:

    Several viruses have been shown to code for proteins that specifically bind to Double-Stranded RNA or RNA with large amounts of secondary structure. These proteins have been implicated in providing interferon resistance to viruses and in inhibiting induction of apoptosis by viruses, and have been suggested to be involved in regulation of viral and cellular protein synthesis in infected cells. This article describes methods for detecting and analyzing viral Double-Stranded RNA-binding proteins.

  • Nucleic acid affinity chromatography: preparation and characterization of Double-Stranded RNA agarose.
    Protein expression and purification, 1995
    Co-Authors: Jeffrey Langland, S. M. Pettiford, Bertram L. Jacobs
    Abstract:

    An improved method for the preparation of a Double-Stranded RNA-coupled resin is described. Periodate-oxidized Double-Stranded RNA, in the form of either purified reovirus Double-Stranded RNA or poly(rl). poly(rC), was covalently attached to agarose-adipic acid hydrazide. The resulting affinity resin had increased specificity for known Double-Stranded RNA binding proteins, as compared to a similar commercially available resin. The application of this resin in the purification and characterization of Double-Stranded RNA binding proteins is described.