Can lambda phage be used as a cloning vector?
Bacteriophage lambda has been in use as a cloning vector for over 25 years, and has been used extensively as an expression vector. The efficiency of packaging and infection, and the simplicity of plaque screening are advantages of lambda as a cloning vector.
Why is lambda phage important in general cloning?
Lambda phage has been of major importance in the study of specialized transduction. Specialized transduction is the process by which a restricted set of bacterial genes are transferred to another bacterium. The genes that get transferred (donor genes) depend on where the phage genome is located on the chromosome.
What is lambda phage used for?
Bacteriophage lambda, a bacterial virus that infects E. coli, has been widely used as a cloning vector. As described in Ch. 21, lambda is a well-characterized virus with both lytic and lysogenic alternatives to its life cycle.
Why would you use bacteriophage λ and cosmid as a cloning vector?
The use of plasmid vectors in the cloning of very large segments of DNA is hampered by the low transformation efficiency of large plasmids. Bacteriophage lambda can be used as a vector to clone efficiently larger segments of DNA. The efficiency by cosmid cloning can be as high as 106 clones per μg of foreign DNA.
How can lambda phage be used as a vector?
Bacteriophages such as lambda phages can also be used as effective vectors for transferring recombinant DNA molecules into cells for cloning. A lambda phage is a bacteriophage that infects E. Coli cells. This phage, like any virus, readily undergoes two types of life cycles – the lytic cycle and the lysogenic cycle.
How bacteriophages can be used as vector?
Phage vectors consist of an essentially complete phage genome, often M13 phage, into which is inserted DNA encoding the protein or peptide of interest (Figure 1). Typically, the remainder of the phage genome is left unchanged and provides the other gene products needed for the phage life cycle.
What are the advantages of using cosmids as gene vectors?
One of the advantages of cosmids for constructing genomic libraries of organisms with large genomes is that they have a cloning capacity about twice that of lambda vectors, i.e., they can accept inserts of up to about 40 kb whereas lambdas are restricted to about 20 kb.
What is a lambda vector?
Why are bacteriophages used as vectors?
Bacteriophages are a better vector than the plasmids due to the following reasons: It can clone the DNA segment of a relatively large size (24 kbp). Every bacteriophage produces one plaque area in the culture through which testing is comparatively easy.
Can bacteriophage be a cloning vector?
There are many types of cloning vectors, but the most commonly used ones are genetically engineered plasmids. Cloning is generally first performed using Escherichia coli, and cloning vectors in E. coli include plasmids, bacteriophages (such as phage λ), cosmids, and bacterial artificial chromosomes (BACs).
What are cosmids and its advantages?
Cosmids are plasmid particles, into which certain specific DNA sequences, namely those for cos sites are inserted. The advantage of using cosmids for cloning is their efficiency is high enough to produce complete genomic library of around 106 clones from1 pg of insert DNA.
What is the importance of Cos sites in cosmids?
Cos sequences are ~200 base pairs long and essential for packaging. They contain a cosN site where DNA is nicked at each strand, 12 bp apart, by terminase. This causes linearization of the circular cosmid with two “cohesive” or “sticky ends” of 12bp. (The DNA must be linear to fit into a phage head.)
Can coliphage Lambda be used as a cloning vector?
Bacteriophage lambda as a cloning vector. Extensive research has been directed toward the development of multipurpose lambda vectors for cloning ever since the potential of using coliphage lambda as a cloning vector was recognized in the late 1970s. An understanding of the intrinsic molecular organization and of the genetic events which det ….
What are lambda vectors?
Bacteriophage Lambda Vectors We have talked about plasmids as vectors for cloning small pieces of DNA. The limitation of this vector is the size of DNA that can be introduced into the cell by transformation. This presents problems when you are trying to create a genomic library of a large genome such as with plants.
How to maximize the number of phage particles produced from lambda vectors?
One important concern when cloning with lambda vectors is that you want to maximize the number of resulting phage particles that contain foreign DNA. Or said another way you want to minimize the number of wild type particles. One approach is through spi selection. This refers to sensitivity to P2 interference.
How to clone Using EMBL 3/4 DNA vector?
EMBL 3/4 vectors have placed the red and gam genes in the stuffer fragment. Thus only those particles from which the stuffer has been replaced can grow well in a P2 lysogen bacterial cell. Cloning in Lambda Vectors Make a partial digest of DNA. Ligate the DNA to the arms of the vector.