Control of development in temperate bacteriophages

Dambly, C; Couturier, Martine; Thomas, René

doi:10.1016/0022-2836(68)90146-0

Cited by 67 publications

(15 citation statements)

References 20 publications

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“…Fitting this observation into the Jacob-Monod model of gene control (100), repressor directly prevents the synthesis of an early protein(s) whose activity is needed for the expression of other phage genes. Consistent with this model, Thomas and his collaborators showed that some prophage genes could and others could not be "transactivated" by superinfection with a heteroimmune phage (39,190,191). The transactivatable class consists principally of genes now known to be expressed late in the infective cycle.…”

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confidence: 91%

Little Lambda, Who Made Thee?

Gottesman

Weisberg

2004

Microbiol Mol Biol Rev

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SUMMARY The study of the bacteriophage λ has been critical to the discipline of molecular biology. It was the source of key discoveries in the mechanisms of, among other processes, gene regulation, recombination, and transcription initiation and termination. We trace here the events surrounding these findings and draw on the recollections of the participants. We show how a particular atmosphere of interactions among creative scientists yielded spectacular insights into how living things work.

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confidence: 91%

Little Lambda, Who Made Thee?

Gottesman

Weisberg

2004

Microbiol Mol Biol Rev

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“…The two x genes that accomplish transactivation are the gene tap in case of y and the newly discovered gene tay in case of y ; these symbols mean transactivator €or psi or y prophage. This differs from transactivation in phages 1 (DAMBLY et al 1968) and P22 (PRELL 1978). Since x is not a satellite phage as P4, for its growth dependence on y and y activities is limited to special conditions, there is also no similarity to the P2-P4 system of reciprocal transactivation ( BARRETT et al 1974).Second, in the course of our experiments several other genes, also under the control of tap and tay, were detected with both y and y.…”

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confidence: 85%

Transactivation of several genes of two native Serratia prophages after superinfection by phage kappa

Steiger

Garbe

Güleke

et al. 1987

J. Basic Microbiol.

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Serratia marcescens HY bacteria must be lysogenic with either prophage y or psi to make it possible for phage kappa to form plaques unless they carry a so-called ink mutation. Genes in y and psi termed any and anp were identified that after infection of ink+ cells are necessary for an effective propagation of these phages as well as of coinfecting kappa phage. When kappa infects y and/or psi-lysogenic cells it transactivates the respective prophage genes by means of two early genes termed tay and tap. It appears that on infection of nonlysogenic ink+ cells kappa damps its own development, provided the regulatory region of the responsible gene is undermethylated. After kappa infection duly to achieve the special methylation of this region seems to be the function of any and anp. There are some more genes in y and psi prophage under the control of tay and tap, concerning in both cases a Dam methylation (recognition sequence GATC) of kappa DNA, a recombination proneness under restricting conditions of kappa DNA not modified by the modification enzyme of HY, and the kappa plaque size. By hybridization studies a region of homology common to y and psi was demonstrated which from its size might comprise all the transactivated genes. The view is supported by genetic data indicating an affinity among the any and anp genes. Investigation of various any mutants were indicative of DNA inversions in this region of the y genome. Surprisingly some of the any mutants had become sensitive in their plaque forming ability to an inhibitory activity exerted by prophage psi. Mutants of psi unable to interfere but still able to lysogenize were isolated. A model is presented accounting for the formation of pleiotropic and nonpleiotropic mutations with Any phenotype and their reversion types. Possible functions of the y genes and their counterparts in psi are discussed.

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“…The endolysin of phage A can be assayed by measurement of the optical density decrease (lysis) of a suspension of EDTA-sensitized E. coli cells (16,18 …”

Section: Methodsmentioning

confidence: 99%

Regulation of the Expression of the N Gene of Bacteriophage Lambda

Greenblatt

1973

Proc. Natl. Acad. Sci. U.S.A.

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A quantitative assay for the N protein of bacteriophage X has been used to study the in vivo regulation of N gene expression. The assay makes use of the observation that in a cell-free protein-synthesizing system from Escherichia coli programmed with XN-DNA the X endolysin is made only if N protein is added to the reaction.The rate of synthesis of N protein in vivo is negatively controlled by the products of the CI and tof genes of the phage. Furthermore, N protein activity is extremely unstable in vivo. During normal cell growth at 350, the halflife of N protein is about 2 min.The protein product of the N gene of phage X is a positive control element required for the expression of almost all other phage genes (1-5). In a gene N-defective phage, or in cells infected in the presence of chloramphenicol-an inhibitor of protein synthesis-phage transcription is almost entirely restricted to the region of nonhomology between phages A and Ximm2' (see Fig. 1) (6-11). The synthesis of an active N protein allows transcription to occur in all other regions of the genome. However, N protein cannot by itself efficiently cause transcription of any region of the genome if initiation of transcription at the early promotors PL and PR (where the subscripts refer to left and right) is prevented by the action of A repressor at the operators . Roberts has suggested that the function of N protein may be to prevent termination of transcription that had originally initiated, independently of N protein action, at the promoters PL and PR (15).I have recently described a direct assay for N protein (16). It is based on the observation that a cell-free protein-synthesizing system programmed with XN-DNA makes the gene R endolysin only if N protein is added to the reaction. The assay is used here to study the in vivo regulation of the expression of the N gene. METHODSMaterials. An Escherichia coli K12 strain JG148 containing lac and ara deletions was used as a source of cell-free extract for in vitro protein synthesis. The DNA used to program the in vitro system in all experiments was derived from the phage XN7N53CI557S7. The methods used for DNA preparation and cell-free protein synthesis were modified only slightly from those of Zubay et al. (17), and have been described (16). In these experiments the source of N protein was an E. coli K12 strain lysogenic for one of the heat-inducible prophages ACIn87X13, XCIs57Ps8c7R6, or ACI867bio11 H1. ACIss7X,3 was obtained from Jan Pero and XCI857bio11 H1 from Helen Greer.AC8I57PsoS7R5 is a recombinant between ACI857P80, obtained from Paul Chadwick, and AS7R5, obtained from Ira Herskowitz. The method used to prepare extracts for N protein assay has been described (16).The Endolysin Assay. The endolysin of phage A can be assayed by measurement of the optical density decrease (lysis) of a suspension of EDTA-sensitized E. coli cells (16,18

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Control of development in temperate bacteriophages

Cited by 67 publications

References 20 publications

Little Lambda, Who Made Thee?

Little Lambda, Who Made Thee?

Transactivation of several genes of two native Serratia prophages after superinfection by phage kappa

Regulation of the Expression of the N Gene of Bacteriophage Lambda

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