The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform

Bentley A. Fane - One of the best experts on this subject based on the ideXlab platform.

  • Genetic Analysis of the fX174 DNA Binding Protein
    1997
    Co-Authors: Bryan Jennings, Bentley A. Fane
    Abstract:

    The fX174 J protein is 37 amino acids in length and contains 12 basic residues. There are no acidic amino acids in the protein. The basic residues are concentrated in two clusters in the N-terminus which are separated by a proline-rich region. To investigate the morphogenetic functions of the J protein and possible mechanisms by which it may bind DNA, a genetic analysis was conducted. Lysine r leucine and arginine r leucine substitutions were generated within the basic amino acid clusters. At least three substitutions were required to eliminate viability in vivo. Lethal Mutants with three or four substitutions exhibit Dominant Lethal phenotypes, indicating that the Mutant proteins retain enough function to interfere with productive assembly. In cells infected with a Dominant Lethal Mutant, noninfectious packaged particles were produced. Infectivity can be restored by second-site suppressors in the viral coat protein which disrupt polar interactions atop the threefold axis of symmetry in the capsid. The viability of strains containing compensating frameshift mutations within the proline-rich region suggests that only the proline residues in this segment are critical for efficient function. q 1997 Academic Press

  • Genetic Analysis of the φX174 DNA Binding Protein
    Virology, 1997
    Co-Authors: Bryan Jennings, Bentley A. Fane
    Abstract:

    Abstract The φX174 J protein is 37 amino acids in length and contains 12 basic residues. There are no acidic amino acids in the protein. The basic residues are concentrated in two clusters in the N-terminus which are separated by a proline-rich region. To investigate the morphogenetic functions of the J protein and possible mechanisms by which it may bind DNA, a genetic analysis was conducted. Lysine → leucine and arginine → leucine substitutions were generated within the basic amino acid clusters. At least three substitutions were required to eliminate viability in vivo. Lethal Mutants with three or four substitutions exhibit Dominant Lethal phenotypes, indicating that the Mutant proteins retain enough function to interfere with productive assembly. In cells infected with a Dominant Lethal Mutant, noninfectious packaged particles were produced. Infectivity can be restored by second-site suppressors in the viral coat protein which disrupt polar interactions atop the threefold axis of symmetry in the capsid. The viability of strains containing compensating frameshift mutations within the proline-rich region suggests that only the proline residues in this segment are critical for efficient function.

Bryan Jennings - One of the best experts on this subject based on the ideXlab platform.

  • Genetic Analysis of the fX174 DNA Binding Protein
    1997
    Co-Authors: Bryan Jennings, Bentley A. Fane
    Abstract:

    The fX174 J protein is 37 amino acids in length and contains 12 basic residues. There are no acidic amino acids in the protein. The basic residues are concentrated in two clusters in the N-terminus which are separated by a proline-rich region. To investigate the morphogenetic functions of the J protein and possible mechanisms by which it may bind DNA, a genetic analysis was conducted. Lysine r leucine and arginine r leucine substitutions were generated within the basic amino acid clusters. At least three substitutions were required to eliminate viability in vivo. Lethal Mutants with three or four substitutions exhibit Dominant Lethal phenotypes, indicating that the Mutant proteins retain enough function to interfere with productive assembly. In cells infected with a Dominant Lethal Mutant, noninfectious packaged particles were produced. Infectivity can be restored by second-site suppressors in the viral coat protein which disrupt polar interactions atop the threefold axis of symmetry in the capsid. The viability of strains containing compensating frameshift mutations within the proline-rich region suggests that only the proline residues in this segment are critical for efficient function. q 1997 Academic Press

  • Genetic Analysis of the φX174 DNA Binding Protein
    Virology, 1997
    Co-Authors: Bryan Jennings, Bentley A. Fane
    Abstract:

    Abstract The φX174 J protein is 37 amino acids in length and contains 12 basic residues. There are no acidic amino acids in the protein. The basic residues are concentrated in two clusters in the N-terminus which are separated by a proline-rich region. To investigate the morphogenetic functions of the J protein and possible mechanisms by which it may bind DNA, a genetic analysis was conducted. Lysine → leucine and arginine → leucine substitutions were generated within the basic amino acid clusters. At least three substitutions were required to eliminate viability in vivo. Lethal Mutants with three or four substitutions exhibit Dominant Lethal phenotypes, indicating that the Mutant proteins retain enough function to interfere with productive assembly. In cells infected with a Dominant Lethal Mutant, noninfectious packaged particles were produced. Infectivity can be restored by second-site suppressors in the viral coat protein which disrupt polar interactions atop the threefold axis of symmetry in the capsid. The viability of strains containing compensating frameshift mutations within the proline-rich region suggests that only the proline residues in this segment are critical for efficient function.

Sue Biggins - One of the best experts on this subject based on the ideXlab platform.

  • Proteolysis Contributes to the Exclusive Centromere Localization of the Yeast Cse4/CENP-A Histone H3 Variant
    Current Biology, 2004
    Co-Authors: Kimberly A. Collins, Suzanne Furuyama, Sue Biggins
    Abstract:

    Kinetochores are the specialized protein structures that form on centromeric DNA and direct chromosome segregation. It is critical that all chromosomes assemble a single kinetochore every cell cycle. One hallmark of all eukaryotic kinetochores is CENP-A, an essential centromeric histone H3 (CenH3) variant. Overexpression of CENP-A causes mislocalization to euchromatin, which could lead to deleterious consequences because CENP-A overexpression is associated with colorectal cancer . Although CENP-A protein levels are important for genomic stability, little is known about the mechanisms of CenH3 regulation. Here, we show that the levels of the budding yeast CenH3, Cse4, are regulated by ubiquitin-proteasome-mediated proteolysis. Because mutation of all Cse4 lysine residues did not completely stabilize the protein, we isolated a Dominant Lethal Mutant, CSE4-351, that was stable. The Cse4-351 protein localized to euchromatin, suggesting that proteolysis prevents CenH3 euchromatic localization. When wild-type Cse4 was fused to a degron signal, the soluble Cse4 protein was rapidly degraded, but the centromere bound Cse4 was stable, indicating that centromere localization protects Cse4 from degradation. Taken together, these data identify proteolysis as one mechanism that contributes to the restricted centromere localization of the yeast CenH3.

Kimberly A. Collins - One of the best experts on this subject based on the ideXlab platform.

  • Proteolysis Contributes to the Exclusive Centromere Localization of the Yeast Cse4/CENP-A Histone H3 Variant
    Current Biology, 2004
    Co-Authors: Kimberly A. Collins, Suzanne Furuyama, Sue Biggins
    Abstract:

    Kinetochores are the specialized protein structures that form on centromeric DNA and direct chromosome segregation. It is critical that all chromosomes assemble a single kinetochore every cell cycle. One hallmark of all eukaryotic kinetochores is CENP-A, an essential centromeric histone H3 (CenH3) variant. Overexpression of CENP-A causes mislocalization to euchromatin, which could lead to deleterious consequences because CENP-A overexpression is associated with colorectal cancer . Although CENP-A protein levels are important for genomic stability, little is known about the mechanisms of CenH3 regulation. Here, we show that the levels of the budding yeast CenH3, Cse4, are regulated by ubiquitin-proteasome-mediated proteolysis. Because mutation of all Cse4 lysine residues did not completely stabilize the protein, we isolated a Dominant Lethal Mutant, CSE4-351, that was stable. The Cse4-351 protein localized to euchromatin, suggesting that proteolysis prevents CenH3 euchromatic localization. When wild-type Cse4 was fused to a degron signal, the soluble Cse4 protein was rapidly degraded, but the centromere bound Cse4 was stable, indicating that centromere localization protects Cse4 from degradation. Taken together, these data identify proteolysis as one mechanism that contributes to the restricted centromere localization of the yeast CenH3.

Suzanne Furuyama - One of the best experts on this subject based on the ideXlab platform.

  • Proteolysis Contributes to the Exclusive Centromere Localization of the Yeast Cse4/CENP-A Histone H3 Variant
    Current Biology, 2004
    Co-Authors: Kimberly A. Collins, Suzanne Furuyama, Sue Biggins
    Abstract:

    Kinetochores are the specialized protein structures that form on centromeric DNA and direct chromosome segregation. It is critical that all chromosomes assemble a single kinetochore every cell cycle. One hallmark of all eukaryotic kinetochores is CENP-A, an essential centromeric histone H3 (CenH3) variant. Overexpression of CENP-A causes mislocalization to euchromatin, which could lead to deleterious consequences because CENP-A overexpression is associated with colorectal cancer . Although CENP-A protein levels are important for genomic stability, little is known about the mechanisms of CenH3 regulation. Here, we show that the levels of the budding yeast CenH3, Cse4, are regulated by ubiquitin-proteasome-mediated proteolysis. Because mutation of all Cse4 lysine residues did not completely stabilize the protein, we isolated a Dominant Lethal Mutant, CSE4-351, that was stable. The Cse4-351 protein localized to euchromatin, suggesting that proteolysis prevents CenH3 euchromatic localization. When wild-type Cse4 was fused to a degron signal, the soluble Cse4 protein was rapidly degraded, but the centromere bound Cse4 was stable, indicating that centromere localization protects Cse4 from degradation. Taken together, these data identify proteolysis as one mechanism that contributes to the restricted centromere localization of the yeast CenH3.