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1.
Mol Microbiol ; 11(6): 1109-16, 1994 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8022280

RESUMO

We have shown previously that some particular mutations in bacteriophage Mu repressor, the frameshift vir mutations, made the protein very sensitive to the Escherichia coli ATP-dependent Clp protease. This enzyme is formed by the association between a protease subunit (ClpP) and an ATPase subunit. ClpA, the best characterized of these ATPases, is not required for the degradation of the mutant Mu repressors. Recently, a new potential ClpP associated ATPase, ClpX, has been described. We show here that this new subunit is required for Mu vir repressor degradation. Moreover, ClpX (but not ClpP) was found to be required for normal Mu replication. Thus ClpX has activities that do not require its association with ClpP. In the pathway of Mu replicative transposition, the block resides beyond the strand transfer reaction, i.e. after the transposition reaction per se is completed, suggesting that ClpX is required for the transition to the formation of the active replication complex at one Mu end. This is a new clear-cut case of the versatile activity of polypeptides that form multi-component ATP-dependent proteases.


Assuntos
Adenosina Trifosfatases/metabolismo , Bacteriófago mu/crescimento & desenvolvimento , Replicação do DNA , Escherichia coli/metabolismo , Recombinação Genética , Replicação Viral , Proteases Dependentes de ATP , ATPases Associadas a Diversas Atividades Celulares , Bacteriófago mu/patogenicidade , Endopeptidase Clp , Proteínas de Escherichia coli , Proteínas de Choque Térmico/metabolismo , Lisogenia , Chaperonas Moleculares , Proteínas Repressoras/metabolismo , Serina Endopeptidases/metabolismo , Proteínas Virais/metabolismo , Proteínas Virais Reguladoras e Acessórias , Virulência
2.
Genetica ; 93(1-3): 27-39, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7813916

RESUMO

Bacteriophage Mu is a transposon and a temperate phage which has become a paradigm for the study of the molecular mechanism of transposition. As a prophage, Mu has also been used to study some aspects of the influence of the host cell growth phase on the regulation of transposition. Through the years several host proteins have been identified which play a key role in the replication of the Mu genome by successive rounds of replicative transposition as well as in the maintenance of the repressed prophage state. In this review we have attempted to summarize all these findings with the purpose of emphasizing the benefit the virus and the host cell can gain from those phage-host interactions.


Assuntos
Bacteriófago mu/genética , Replicação do DNA , Elementos de DNA Transponíveis , Bacteriófago mu/crescimento & desenvolvimento , Sequência de Bases , Regulação Viral da Expressão Gênica , Genoma Viral , Modelos Genéticos , Dados de Sequência Molecular , Nucleotidiltransferases/metabolismo , Transposases , Ativação Viral
3.
EMBO J ; 11(13): 5121-7, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1464331

RESUMO

The importance of proteases in gene regulation is well documented in both prokaryotic and eukaryotic systems. Here we describe the first example of genetic regulation controlled by the Escherichia coli Clp ATP-dependent serine protease. Virulent mutants of bacteriophage Mu, which carry a particular mutation in their repressor gene (vir mutation), successfully infect Mu lysogens and induce the resident Mu prophage. We show that the mutated repressors have an abnormally short half-life due to an increased susceptibility to Clp-dependent degradation. This susceptibility is communicated to the wild type repressor present in the same cell, which provides the Muvir phages with their trans-dominant phenotype. To our knowledge this is the first case where the instability of a mutant protein is shown to trigger the degradation of its wild type parent.


Assuntos
Bacteriófago mu/patogenicidade , Escherichia coli/enzimologia , Proteínas de Choque Térmico , Serina Endopeptidases/metabolismo , Proteases Dependentes de ATP , Sequência de Aminoácidos , Sequência de Bases , Mapeamento Cromossômico , DNA Fúngico , Regulação Enzimológica da Expressão Gênica , Hidrólise , Dados de Sequência Molecular , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo , Proteínas Virais Reguladoras e Acessórias , Virulência/genética
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