Translation initiation of bacteriophage lambda gene cII requires integration host factor

Mahajna, Jamal; Oppenheim, Amos B.; Rattray, Alison J.; Gottesman, Max E.

doi:10.1128/jb.165.1.167-174.1986

Cited by 56 publications

(35 citation statements)

References 24 publications

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“…If either or both of the possible IHF binding sequences contribute to the regulation of rha expression, control must be exerted posttranscriptionally because these sites are far removed from the promoter. Studies by Mahajna et al (22) serve as a precedent for proposing translational regulation by IHF. Those workers proposed that perhaps IHF binding to RNA controls translation of the cII mRNA.…”

Section: Discussionmentioning

confidence: 99%

Identification of related genes in phages phi 80 and P22 whose products are inhibitory for phage growth in Escherichia coli IHF mutants

Henthorn

Friedman

1995

J Bacteriol

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Section: Discussionmentioning

confidence: 99%

Identification of related genes in phages phi 80 and P22 whose products are inhibitory for phage growth in Escherichia coli IHF mutants

Henthorn

Friedman

1995

J Bacteriol

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“…Plasmids YEp352 and pRG1, which were transformed into the protease-deficient yeast strain C13-ABYS86 (Table 1), have been described by Damak et al (10). Plasmid pJM1039-25 is derived from plasmid pJM1039, which has been described by Mahajna et al (24).…”

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confidence: 99%

Anti-Cdc25 antibodies inhibit guanyl nucleotide-dependent adenylyl cyclase of Saccharomyces cerevisiae and cross-react with a 150-kilodalton mammalian protein.

Gross¹,

Marbach²,

Engelberg³

et al. 1992

Mol. Cell. Biol.

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The CDC25 gene product of the yeast Saccharomyces cerevisiae has been shown to be a positive regulator of the Ras protein. The high degree of homology between yeast RAS and the mammalian proto-oncogene ras suggests a possible resemblance between the mammalian regulator of Ras and the regulator of the yeast Ras (Cdc25). On the basis of this assumption, we have raised antibodies against the conserved C-terminal domain of the Cdc25 protein in order to identify its mammalian homologs. Anti-Cdc25 antibodies raised against a 13-galactosidase-Cdc25 fusion protein were purified by immunoaffinity chromatography and were shown by immunoblotting to specifically recognize the Cdc25 portion of the antigen and a truncated Cdc25 protein, also expressed in bacteria. These antibodies were shown both by immunoblotting and by immunoprecipitation to recognize the CDC25 gene product in wild-type strains and in strains overexpressing Cdc25. The anti-Cdc25 antibodies potently inhibited the guanyl nucleotide-dependent and, -3-fold less potently, the Mn2'-dependent adenylyl cyclase activity in S. cerevisiae. The anti-Cdc25 antibodies do not inhibit cyclase activity in a strain harboring and lacking the CDC25 gene product. These results support the view that Cdc25, Ras2, and Cdc35/Cyrl proteins are associated in a complex. Using these antibodies, we were able to define the conditions to completely solubilize the Cdc25 protein. The results suggest that the Cdc25 protein is tightly associated with the membrane but is not an intrinsic membrane protein, since only EDTA at pH 12 can solubilize the protein. The anti-Cdc25 antibodies strongly cross-reacted with the C-terminal domain of the Cdc25 yeast homolog, Sdc25. Most interestingly, these antibodies also cross-reacted with mammalian proteins of -150 kDa from various tissues of several species of animals. These interactions were specifically blocked by the 1B-galactosidase-Cdc25 fusion protein.ras is a family of proto-oncogenes which are highly conserved in evolution from yeasts to humans. ras genes are expressed in most mammalian tissues, in which it is believed that they play a major role in mediating the transduction of proliferative signals. Nevertheless, the pathway that leads to the activation of ras and its effector, as well as their exact function in mammalian cells, remains unknown (2). The products of mammalian ras genes are membrane-associated GTP-binding proteins which exert their effect on the putative effector(s) in their GTP-bound form (4) and require facilitated hydrolysis of the GTP by GTPase-activating protein to inactivate the protein (25). GDP has a low rate of dissociation from these proteins, and reactivation requires an exchange factor. Although exchange activity of guanyl nucleotides bound to mammalian Ras has been detected in mammalian cells (14,37,38), the factors which catalyze guanyl nucleotide exchange have not yet been identified.In Saccharomyces cerevisiae, which contains two RAS genes, the Ras effector is adenylyl cyclase, the product of the CDC35ICYRI gene (...

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“…It is difficult to imagine that a transcriptional modulation could occur at the transcriptional initiation stage as the pR promoter is located several kilobases upstream of the roi gene. An alternative hypothesis implicates IHF control of Roi expression at a posttranscriptional stage, as postulated for cII translation initiation (19). As no evidence exists for the interaction of IHF with RNA and the IHF binding site is located far downstream from the initiation codon, we have to consider the possibility that Roi and IHF play a role in the release of a roi transcript affected in its translatability.…”

Section: Discussionmentioning

confidence: 99%

Phage HK022 Roi protein inhibits phage lytic growth in Escherichia coli integration host factor mutants

Clerget

Boccard

1996

J Bacteriol

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Temperate coliphage HK022 requires integration host factor (IHF) for lytic growth. The determinant responsible for this requirement was identified as a new gene (roi) located between genes P and Q. This gene encodes a DNA-binding protein (Roi) containing a helix-turn-helix motif. We have shown that Roi binds a site within its own gene that is closely linked to an IHF binding site. By gel retardation experiments, we have found that IHF binding stabilizes the interaction of Roi with its gene. We have isolated three independent phage mutants that are able to grow on an IHF ؊ host. They carry different mutations scattered in the roi gene and specifying single amino-acid changes. The interactions of all three Roi mutant proteins with the Roi binding site differed from that of the wild type. Roi displays strong similarities, in its C-terminal half, to two putative DNA-binding proteins of bacteriophage P1: Ant1 and KilA. The mode of action of the Roi protein and the possibility that IHF is modulating the expression and/or the action of Roi are discussed.HK022 is a temperate coliphage, a member of the lambdoid family, to which belong phages lambda, 80, 21, P22, and 434. These phages share a common genetic organization which allows the exchange of information, genes or blocks of genes, among them (6). Some genes are always required for the phage to form plaques, while other genes are not essential for phage development in standard hosts but can play important roles in certain circumstances. These have been called accessory genes (6). Some accessory genes are carried by some of the phages in the family but not by others. It is known that phage lambda can form plaques in a host deficient in the integration host factor (IHF). In contrast, HK022 (8) and 80 (20, 21) do not form plaques in a host deficient in IHF. The basis of the HK022 IHF requirement was unknown and is the subject of this study.IHF is a small DNA-binding protein belonging to the family of prokaryotic histone-like proteins. It has remarkable DNAbinding properties: unlike most histone-like proteins, it binds preferentially to specific sites in DNA, makes most of its sequence-specific contacts in the minor groove of DNA, and is one of the strongest DNA-bending proteins (reviewed in references 22 and 23). In bacteria and their mobile genetic elements, IHF participates in a number of cellular processes such as DNA replication, site-specific recombination, bacteriophage packaging, and the positive and negative control of the expression of certain genes (reviewed in references 9, 10, and 23).Bacteriophages Mu, lambda cin-1, and 80 require IHF for plaque formation. The requirement of IHF for growth of Mu and lambda cin-1 appears to be satisfied by IHF's binding to a single identified site in each phage (14, 15). In both cases, IHF exerts its effect at the transcriptional level by modulating transcription from a promoter. For phage 80, a function (rha) which is inhibitory for growth of this phage in IHF Ϫ cells has been described; it maps in the QSR gene region of 80...

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Translation initiation of bacteriophage lambda gene cII requires integration host factor

Cited by 56 publications

References 24 publications

Identification of related genes in phages phi 80 and P22 whose products are inhibitory for phage growth in Escherichia coli IHF mutants

Identification of related genes in phages phi 80 and P22 whose products are inhibitory for phage growth in Escherichia coli IHF mutants

Anti-Cdc25 antibodies inhibit guanyl nucleotide-dependent adenylyl cyclase of Saccharomyces cerevisiae and cross-react with a 150-kilodalton mammalian protein.

Phage HK022 Roi protein inhibits phage lytic growth in Escherichia coli integration host factor mutants

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