PubMed HealthSearch

PubMed · 8380784

A new lambda RES vector with a built-in Tn1721-encoded excision system.

Abstract

A new lambda replacement vector for construction of genomic libraries was developed which allows the excision of cloned fragments by site-specific recombination from the lambda DNA and conversion into autonomously replicating plasmids. The vector system, derived from lambda EMBL4, is called lambda RES. It contains two recognition sites for site-specific recombination from Tn1721 on both sides of the replacement fragment of lambda EMBL4. Additionally, on one side, there is a plasmid replication origin from Rtsl with a kanamycin-resistance (KmR) marker. DNA fragments in the range of 8-14 kb may be inserted between BamHI or Sall sites in the lambda vector. Efficient excision and conversion of plaque-forming units into KmR colonies are obtained by infection of Escherichia coli strains harbouring Tn1739tnpR on a F' plasmid. Tn1739tnpR is a derivative of Tn1721 with a chloramphenicol-resistance-encoding gene (CmR), the lambda cI repressor gene, and a further copy of the resolvase-encoding tnpR gene under control of the tac promoter.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J Altenbuchner. 1993-01-15. A new lambda RES vector with a built-in Tn1721-encoded excision system.. https://doi.org/10.1016/0378-1119(93)90540-j

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Phage recovery by electroporation of naked DNA into host cells avoids the use of packaging extracts.

In this paper, we describe the application of electroporation to deliver phage DNA into bacterial cells in order to recover it as phage particles. The methodology represents a quicker and cheaper alternative to the use of packaging extracts to rescue phage clones stored as naked DNAs. Furthermore, our data demonstrate that there were not rearrangements or recombinations between phage DNAs when a mixture of different DNAs was electroporated, suggesting the use of electroporation as a reliable method for construction of gene libraries.

Bacteriophage lambda

Optical mapping of DNA polymerase I action and products.

Single molecule approaches to the characterization of biochemical systems offer an intrinsically simple and direct approach to address difficult, previously unyielding problems. Optically based approaches have recently been used to construct high resolution, ordered restriction maps from a variety of clone types. Advancements in surface technologies have enabled the reliable elongation and fixation of large DNA molecules onto specially derivatized substrates with retention of biochemical accessibility. In this study, the addition of fluorescently labeled nucleotides to surface-mounted DNA molecules by the action of DNA polymerase I is investigated using fluorescence microscopy to image individual template molecules. Molecules undergoing nick translation and containing only a few fluorochromes are readily imaged. These novel results suggest that surface-bound molecules may serve as a substrate for a broad range of enzymatic actions, and may offer new routes to analysis when coupled to advanced imaging techniques.

Bacteriophage lambda

Trapping of megabase-sized DNA molecules during agarose gel electrophoresis.

Megabase DNA molecules become trapped in agarose gels during electrophoresis if the electric field exceeds a few volts per cm. Fluorescence microscopy reveals that these molecules invariably arrest in U-shaped conformations. The field-vs.-size dependence for trapping indicates that a critical molecular tension is required for trapping. The size of unligated lambda-ladders, sheared during gel electrophoresis at a given field, coincides with the size of molecules trapped at that field, suggesting that both processes occur through nick melting near the vertex of the U-shape. Consistently, molecules nicked by exposure to UV radiation trap more readily than unexposed ones. The critical trapping tension at the vertex is estimated to be 15 pN, a force sufficient to melt nicks bent around gel fibers, and, according to our model, trap a molecule. Strategies to reduce molecular tension and avoid trapping are discussed.

Bacteriophage lambda