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Shoshy Altuvia - One of the best experts on this subject based on the ideXlab platform.

  • fhla repression by oxys RNA kissing complex formation at two sites results in a stable antisense target RNA complex
    Journal of Molecular Biology, 2000
    Co-Authors: Liron Argaman, Shoshy Altuvia
    Abstract:

    OxyS is a Small Untranslated RNA that is induced in response to oxidative stress in Escherichia coli. This Small RNA acts as a global regulator affecting the expression of multiple genes. OxyS represses the translation of fhlA, a transcriptional activator for formate metabolism. Previously, we have shown that fhlA repression by OxyS is mediated through base-pairing with a short sequence overlapping the ribosome binding site. Here we show that the OxyS-fhlA interaction involves a second site residing further downstream, within the coding region of fhlA. Mutations that disrupt pairing at this site affect the ability of OxyS to prevent 30 S ribosomes from binding to fhlA mRNA. Structure probing of fhlA mRNA demonstrates that both sites reside in the loops of two stem-loop structures. OxyS-fhlA pairing analysis shows that OxyS binds wild-type fhlA with an apparent dissociation constant of 25 nM, indicating that kissing complex formation between OxyS and fhlA results in a stable antisense-target complex. Mutations at either site, which disrupt pairing of OxyS to fhlA, decrease the stability of this complex. Our results indicate that kissing complex formation is sufficient to repress fhlA translation by OxyS.

  • The Escherichia coli OxyS regulatory RNA represses fhlA translation by blocking ribosome binding
    The EMBO journal, 1998
    Co-Authors: Shoshy Altuvia, Aixia Zhang, Liron Argaman, Anita Tiwari, Gisela Storz
    Abstract:

    OxyS is a Small Untranslated RNA which is induced in response to oxidative stress in Escherichia coli. This novel RNA acts as a global regulator to activate or repress the expression of as many as 40 genes, including the fhlA-encoded transcriptional activator and the rpoS-encoded sigma(s) subunit of RNA polymerase. Deletion analysis of OxyS showed that different domains of the Small RNA are required for the regulation of fhlA and rpoS. We examined the mechanism of OxyS repression of fhlA and found that the OxyS RNA inhibits fhlA translation by pairing with a short sequence overlapping the Shine-Dalgarno sequence, thereby blocking ribosome binding/translation.

Liron Argaman - One of the best experts on this subject based on the ideXlab platform.

  • fhla repression by oxys RNA kissing complex formation at two sites results in a stable antisense target RNA complex
    Journal of Molecular Biology, 2000
    Co-Authors: Liron Argaman, Shoshy Altuvia
    Abstract:

    OxyS is a Small Untranslated RNA that is induced in response to oxidative stress in Escherichia coli. This Small RNA acts as a global regulator affecting the expression of multiple genes. OxyS represses the translation of fhlA, a transcriptional activator for formate metabolism. Previously, we have shown that fhlA repression by OxyS is mediated through base-pairing with a short sequence overlapping the ribosome binding site. Here we show that the OxyS-fhlA interaction involves a second site residing further downstream, within the coding region of fhlA. Mutations that disrupt pairing at this site affect the ability of OxyS to prevent 30 S ribosomes from binding to fhlA mRNA. Structure probing of fhlA mRNA demonstrates that both sites reside in the loops of two stem-loop structures. OxyS-fhlA pairing analysis shows that OxyS binds wild-type fhlA with an apparent dissociation constant of 25 nM, indicating that kissing complex formation between OxyS and fhlA results in a stable antisense-target complex. Mutations at either site, which disrupt pairing of OxyS to fhlA, decrease the stability of this complex. Our results indicate that kissing complex formation is sufficient to repress fhlA translation by OxyS.

  • The Escherichia coli OxyS regulatory RNA represses fhlA translation by blocking ribosome binding
    The EMBO journal, 1998
    Co-Authors: Shoshy Altuvia, Aixia Zhang, Liron Argaman, Anita Tiwari, Gisela Storz
    Abstract:

    OxyS is a Small Untranslated RNA which is induced in response to oxidative stress in Escherichia coli. This novel RNA acts as a global regulator to activate or repress the expression of as many as 40 genes, including the fhlA-encoded transcriptional activator and the rpoS-encoded sigma(s) subunit of RNA polymerase. Deletion analysis of OxyS showed that different domains of the Small RNA are required for the regulation of fhlA and rpoS. We examined the mechanism of OxyS repression of fhlA and found that the OxyS RNA inhibits fhlA translation by pairing with a short sequence overlapping the Shine-Dalgarno sequence, thereby blocking ribosome binding/translation.

Gisela Storz - One of the best experts on this subject based on the ideXlab platform.

  • The Escherichia coli OxyS regulatory RNA represses fhlA translation by blocking ribosome binding
    The EMBO journal, 1998
    Co-Authors: Shoshy Altuvia, Aixia Zhang, Liron Argaman, Anita Tiwari, Gisela Storz
    Abstract:

    OxyS is a Small Untranslated RNA which is induced in response to oxidative stress in Escherichia coli. This novel RNA acts as a global regulator to activate or repress the expression of as many as 40 genes, including the fhlA-encoded transcriptional activator and the rpoS-encoded sigma(s) subunit of RNA polymerase. Deletion analysis of OxyS showed that different domains of the Small RNA are required for the regulation of fhlA and rpoS. We examined the mechanism of OxyS repression of fhlA and found that the OxyS RNA inhibits fhlA translation by pairing with a short sequence overlapping the Shine-Dalgarno sequence, thereby blocking ribosome binding/translation.

George V Stauffer - One of the best experts on this subject based on the ideXlab platform.

  • the gcvb gene encodes a Small Untranslated RNA involved in expression of the dipeptide and oligopeptide transport systems in escherichia coli
    Molecular Microbiology, 2000
    Co-Authors: Mark L Urbanowski, Lorraine T Stauffer, George V Stauffer
    Abstract:

    The Escherichia coli gcvB gene encodes a Small RNA transcript that is not translated in vivo. Transcription from the gcvB promoter is activated by the GcvA protein and repressed by the GcvR protein, the transcriptional regulators of the gcvTHP operon encoding the enzymes of the glycine cleavage system. A strain carrying a chromosomal deletion of gcvB exhibits normal regulation of gcvTHP expression and glycine cleavage enzyme activity. However, this mutant has high constitutive synthesis of OppA and DppA, the periplasmic-binding protein components of the two major peptide transport systems normally repressed in cells growing in rich medium. The altered regulation of oppA and dppA was also demonstrated using oppA–phoA and dppA–lacZ gene fusions. Although the mechanism(s) involving gcvB in the repression of these two genes is not known, oppA regulation appears to be at the translational level, whereas dppA regulation occurs at the mRNA level.

Phoebe L. Stewart - One of the best experts on this subject based on the ideXlab platform.

  • cryoelectron microscopy imaging of recombinant and tissue derived vaults localization of the mvp n termini and vparp
    Journal of Molecular Biology, 2004
    Co-Authors: Yeshi Mikyas, Miriam Makabi, Sujna Ravalfernandes, Lea Harrington, Phoebe L. Stewart, Valerie A. Kickhoefer, Leonard H. Rome
    Abstract:

    The vault is a highly conserved ribonucleoprotein particle found in all higher eukaryotes. It has a barrel-shaped structure and is composed of the major vault protein (MVP); vault poly(ADP-ribose) polymerase (VPARP); telomerase-associated protein 1 (TEP1); and Small Untranslated RNA (vRNA). Although its strong conservation and high abundance indicate an important cellular role, the function of the vault is unknown. In humans, vaults have been implicated in multidrug resistance during chemotherapy. Recently, assembly of recombinant vaults has been established in insect cells expressing only MVP. Here, we demonstrate that co-expression of MVP with one or both of the other two vault proteins results in their co-assembly into regularly shaped vaults. Particles assembled from MVP with N-terminal peptide tags of various length are compared. Cryoelectron microscopy (cryoEM) and single-particle image reconstruction methods were used to determine the structure of nine recombinant vaults of various composition, as well as wild-type and TEP1-deficient mouse vaults. Recombinant vaults with MVP N-terminal peptide tags showed inteRNAl density that varied in size with the length of the tag. Reconstruction of a recombinant vault with a cysteine-rich tag revealed 48-fold rotational symmetry for the vault. A model is proposed for the organization of MVP within the vault with all of the MVP N termini interacting non-covalently at the vault midsection and 48 copies of MVP forming each half vault. CryoEM difference mapping localized VPARP to three density bands lining the inner surface of the vault. Difference maps designed to localize TEP1 showed only weak density inside of the caps, suggesting that TEP1 may interact with MVP via a Small interaction region. In the absence of atomic-resolution structures for either VPARP or TEP1, fold recognition methods were applied. A total of 21 repeats were predicted for the TEP1 WD-repeat domain, suggesting an unusually large β-propeller fold.