Infection by phage t4 initiates profound changes in cellular metabolism, directed in large part towards an increase in the destruction of host dna and increase of phage dna synthesis. Bacteriophage vectors have potential as gene transfer and vaccine delivery vectors because of their low cost, safety and physical stability. Thegenesthatcodeforproteins ofdefinedfunction areshownin. However, bacteriophage research did not lead the genomics revolution, which is clearly dominated by bacterial genomics. Switches in bacteriophage lambda development annual. Regulation of gene expression in bacteriophage lambda. The int gene of bacteriophage p2 is the only viral gene necessary for the integration of p2 into the escherichia coli host chromosome.
Transcriptional regulation of bacteriophage lambda. Therex gene product excludes phage t4 ri mutants from x lysogens. This lamda phage lecture explains the lysogenic cycle of lamda bacteriophage. When lambda exists as a prophage, its dna is integrated into the host genome and most of its gene expression is repressed. We therefore performed experiments to examine phage. Also the first genome to be sequenced was a bacteriophage. Scott meyers, peter friedland, knowledgebased simulation of genetic regulation in bacteriophage lambda, nucleic acids research, volume 12, issue 1part1. Toxin production by corynebacterium diphtheriae is mediated by a gene carried by a beta phage. Retroregulation of the int gene of bacteriophage lambda. The regulation of integrative recombination by the b2 region and the cii gene of bacteriophage lambda. Previous experiments have shown that the hima gene of e. Transcription regulation via effects on rna polymerases exercises 18. The tof gene product also known as cro orfed reduces transcription of the ci gene and of the plscripton.
Infection by phage produces many progeny and breaks open lyses the host bacterium lysogeny. Regulation of int gene expression in bacteriophage p2. Secondary mutants, selected for growth on reca, lie within the immunity region to the right of gene ci and appear identical to the cro mutants of eisen et al. Integration host factor assembly at the cohesive end site. Posttranscriptional control of bacteriophage lambda gene.
Proceedings of the national academy of sciences 2008, 105 15, 58275832. We have tested the effects of a hima mutation on the establishment and maintenance of. Lambda consists of two types of life cycles, the lytic and lysogenic. Values for all interaction parameters of the model have been.
Nonessential genes have been identified by isolation of deletion or substitution mutations. When synthesis is complete, the bacterial host cell is lysed and the new phages are released into the. The wild type of this virus has a temperate life cycle that allows it to either reside within the genome of its host through lysogeny or enter into a lytic. Thus, bacteriophage can be viewed as model systems for animal cell viruses. Bacteriophage phage are obligate intracellular parasites that multiply inside bacteria by making use of some or all of the host biosynthetic machinery i. Values for all interaction parameters of the model have been evaluated at 37 degrees c, 0. Gene regulation in bacteria and bacteriophages flashcards. Transcriptional regulation in bacteriophage lambda three basic phenomena were discovered. In order to study in detail the looping of dna mediated by the protein, tagfree repressor and a lossofcooperativity mutant were expressed in li and purified by 1 ammonium sulfate fractionation, 2 anionexchange chromatography and 3 heparin affinity. Implications for viral dna packaging and bacterial gene regulation saurarshi j. Historically, they were used to define gene structure and gene regulation.
Switches in bacteriophage lambda development amos b. Promoter for transcription from the int gene under positive regulation by cii and. The lysislysogeny decision of bacteriophage lambda. Infection by phage t4 initiates profound changes in cellular metabolism, directed in large part towards an increase in the destruction of host dna and increase of. Knowledgebased simulation of genetic regulation in bacteriophage lambda. Most lambda genes are under the control, directly or indirectly, of the pr and pl promoters pl is similar to pr, but the promoter itself is not directly involved in ci regulation. Quantitative model for gene regulation by lambda phage. The chemical halflife of n protein, determined by its disappearance on polyacrylamide gels following pulsechase labeling, increases about three. The model incorporates a general theory for quantitatively interpreting cooperative sitespecific equilibrium binding data. A new look at bacteriophage lambda genetic networks f les sequences cos du bacteriophage.
Learn vocabulary, terms, and more with flashcards, games, and other study tools. The functional halflife of the phage n gene product, measured by complementation, is increased about 5fold in ion mutant strains, from 2 min to 10 min. The excision process eliminates the need to subclone dna inserts from the lambda phage into a plasmid by restriction digestion and ligation. After infection, the phage dna integrates into the host genome and resides there passively no progeny no lysis of the host can subsequently lyse lysogeny. Measuring a gene regulation function grf in individual e. A the grf is the dependence of the production rate of a target promoter y axis on the concentration of one or more transcription factors x axis. Received 15 december 1981 the int gene of bacteriophage lambda can be. Regulation of gene expression entails a broad range of mechanisms that are used by cells to develop or diminish the production of specific gene products protein or rna, and is informally termed. Bacteriophage means to eat bacteria, and are called so because.
Dna looping can enhance lysogenic ci transcription in phage lambda. Regulation of gene expression in bacteria and phage. Gussin department of zoology, university of iowa, iowa city, iowa 52242 manuscript received july 1,1982 revised copy accepted august 5,1982 abstract complementation tests among previously isolated rex mutants of bacterio. Expression profiling via novel multiplex assay allows rapid assessment of gene regulation in defined signalling. Request pdf revisited gene regulation in bacteriophage. Transcriptional regulation of bacteriophage lambda last updated jun 23, 2019. A lambda insertion type cdna cloning vector, lambda zap, has been constructed.
Temperate phage reside in the host genome and do not kill the host, whereas lytic phage cause lysis of their hosts when they infect bacteria. A statistical thermodynamic model has been developed to account for the cooperative interactions of the bacteriophage lambda repressor with the lambda right operator. Transcriptional regulation in bacteriophage lambda. Sitespecific enthalpic regulation of dna transcription at. Sanyal, tengchieh yang, and carlos enrique catalano department of medicinal chemistry, school of pharmacy, university of washington, h172 health sciences building, box 357610, seattle, washington 98195, united states s supporting. Bacteriophage lambda l transcriptional switches can regulate cellular decisions lysis or lysogeny lysis. Purification of bacteriophage lambda repressor sciencedirect. Downstream regulation of int gene expression by the b2 region in phage lambda. Pdf regulation of bacteriophage lambda dna replication. Regulation the expression gene bacteriophage lambda. Termination of transcription most likely occurs in the regions between genes nand ciii, between genes tof and 0, and between genes p and q. Pdf on jan 1, 1968, m h green and others published regulation of bacteriophage lambda dna replication find, read and cite all the research you need on researchgate. Oppenheimf, slkan gottesman and max gottekman biochemical genetics section, laboratory of molecular biology national cancer institute, national institutes of health bethesda, md 20205, u. The 0, control system of bacteriophage lambda cbbp lund.
Guarneros g, galindo jm 1979 the regulation of integrative recombination by the b2 region and the cii gene of bacteriophage 2. Bacteriophage lambda repressor controls the lysogenylytic growth switch after infection of e. There are many similarities between bacteriophages and animal cell viruses. Recently, the lambda gene expression profile has also been investigated systematically. In the first moments of infection, lambda makes a decision either to proceed with lysis. Introduction to bioinformatics gene regulation and. Operon will be used here for a group of linked genes whose transcription requires the availability in cis of a common promoter.
In vivo gene delivery and expression by bacteriophage. Lysis of bacterial cell envelope and release of progeny phage. This gene is situated between the phage attachment site, attp, and the repressor c gene, and is cotranscribed with c from the pc promoter, towards attp. Knowledgebased simulation of genetic regulation in. First, after infection of the host bacterium, a decision between lytic or lysogenic development is made that is dependent upon environmental signals and the number of infecting phages per cell. Spherical phages with single stranded dna such as phix174. Autogenous regulation of the rega gene of bacteriophage t4. Derepression of translation yumei liang, rongxuan wei, tien hsu, charlene alford, myra dawson and jim karam department of biochemistry and molecular biology, medical university of south carolina, charleston, south carolina 29425 manuscript received january 15, 1988. There are three key features, which characterize the network. A revised model of the lambda genetic switch includes extra cooperativity through octamerization of the ci repressor protein, mediated by longrange dna looping.
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