Topic
Lambda phage
About: Lambda phage is a research topic. Over the lifetime, 1609 publications have been published within this topic receiving 84675 citations. The topic is also known as: Enterobacteria phage lambda.
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TL;DR: Since Fis stimulates both excision and integration, depending on the presence or absence of Xis, respectively, it is concluded that Xis binding to X1 is the key determinant directing the formation of an excisive complex.
Abstract: Fis is a small, basic, site-specific DNA-binding protein present in Escherichia coli. A Fis-binding site (F) has been previously identified in the attP recombination site of phage lambda (J. F. Thompson, L. Moitoso de Vargas, C. Koch, R. Kahmann, and A. Landy, Cell 50:901-908, 1987). The present study demonstrates that in the absence of the phage-encoded Xis protein, the binding of Fis to F can stimulate integrative recombination and therefore increase the frequency of lambda lysogeny in vivo. Additionally, Fis exerts a stimulatory effect on both integration and lysogeny that is independent of binding to the attP F site. Maintenance of the lysogenic state also appears to be enhanced in the presence of Fis, as shown by the increased sensitivity of lambda prophages encoding temperature-sensitive repressors to partial thermoinduction in a fis mutant. In the presence of Xis, however, Fis binding to F interferes with integration by stimulating excision, the competing back-reaction. Since Fis stimulates both excision and integration, depending on the presence or absence of Xis, respectively, we conclude that Xis binding to X1 is the key determinant directing the formation of an excisive complex.
71 citations
TL;DR: A precursor head of phage lambda is synthesized after induction of cells lysogenic for λD-F- and λA- (head-defective) mutants and can be assayed by complementation in vitro and purified by CsCl gradient centrifugation and sucrose gradient sedimentation.
Abstract: A precursor head of phage lambda is synthesized after induction of cells lysogenic for λD-F- and λA- (head-defective) mutants. This precursor head can be assayed by complementation in vitro and can be purified by CsCl gradient centrifugation and sucrose gradient sedimentation. The precursor head contains no DNA and has the same dimensions as the petit λ particle. It can be packed with λ DNA in an extract from induced Escherichia coli lysogenic for a λE- mutant.
70 citations
TL;DR: It is shown that the lambda display system has a unique ability to display, at high density, proteins ranging in size from a few to at least 300 amino acid residues, which permits attenuation of the size bias in the selection procedure and offers a sensitive plaque assay that permits us to do away with the ligand background without unduly increasing the number of selection cycles.
70 citations
TL;DR: The results indicate that the intracellular level of the E. coli methylase determines the DNA methylation pattern.
Abstract: Extrachromosomal plasmid DNA is transiently undermethylated in Escherichia coli during amplification in the presence of chloramphenicol. In addition, undermethylation of phage lambda DNA was observed after thermal induction of a lambda c1857 lysogen while the integrated lambda phage DNA was found to be fully methylated. These methylation pattern changes occur under conditions (extensive replication) in which the intracellular methylase level becomes limiting. In an E. coli strain that harbors a plasmid that carries the dam methylase gene and therefore overproduces dam methylase, there is no undermethylation of dam sites in either of the extrachromosomal DNAs. The sites that are methylated by the mec methylase in both plasmid and lambda phage DNAs were undermethylated in the dam overproducer as well. These results indicate that the intracellular level of the E. coli methylase determines the DNA methylation pattern.
70 citations
TL;DR: A full-length cDNA copy of CPMV M RNA has been cloned downstream of a phage lambda promoter in the plasmid pPMI and results obtained confirm that the AUG at position 161 is used to direct the synthesis of a 105K protein in vitro and the detection of a 58Kprotein in infected cowpea protoplasts suggests that it is also used in vivo.
70 citations