How lambda phage can be used as a cloning vector?
The phage particle recognizes and binds to its host, E. coli, causing DNA in the head of the phage to be ejected through the tail into the cytoplasm of the bacterial cell. Usually, a “lytic cycle” ensues, where the lambda DNA is replicated many times and the genes for head, tail and lysis proteins are expressed.
Why would you use bacteriophage λ and cosmid as a cloning vector?
Bacteriophage lambda can be used as a vector to clone efficiently larger segments of DNA. Such vectors are, therefore, designated as cosmids. Cosmid hybrids can be packaged into lambda phage heads and this allows the cloning of the DNA fragments up to 52 kb.
Is lambda bacteriophage a cloning vector?
Bacteriophage lambda is the most studied and best characterized of all the bacterial extrachromosomal elements. Over the past 20 years, lambda has served as model system for the study of bacteriophage morphogenesis, DNA replication, and gene regulation. It also serves as one of the first molecular cloning vectors.
What are the advantages of lambda phage vector?
The major advantage of the λ phage vector is its high transformation efficiency, about 1000 times more efficient than the plasmid vector. Figure 9-A-4. Schematic drawing of the DNA cloning using λ phages as vectors. The DNA to be cloned is first inserted into the λ DNA, replacing a nonessential region.
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.
How is cosmid used as a cloning vector?
For cloning into cosmid vectors, cosmid DNA and the DNA to be cloned are digested with restriction endonucleases and joined by ligase. The long concatenated DNA structures that are produced resemble the conformation of the λ DNA that is packaged into λ phage heads. This DNA can be packaged into λ phage heads in vitro.
What is a vector derived from lambda phage DNA having single restriction site known as?
A cosmid is a type of hybrid plasmid that contains a Lambda phage cos sequence. They are often used as a cloning vector in genetic engineering.
What are cloning sites in a cloning vector?
Cloning sites is that sites in the vector in which cloning of recombinant DNA takes place . Two sites in PBR322 is ampicillin and tetracycline. pBR322 is a plasmid and was one of the first widely used E.
Why is bacteriophage used as a vector?
The use of phage particles as vector imposes a limitation on the size of foreign DNA. which can be cloned, because the capacity of phage head is only limited, and if the size of foreign DNA is too long, size of phage DNA may not be accommodated in phage head.
How does lambda phage replication?
Viral replication machinery replicates lambda genome by rolling circle, producing linear genome concatemers. Terminase binds to 5′ genome concatemers, and by binds to empty procapsids. Viral genomic DNA is packaged in an energy dependent manner, and the terminase cleaves the cos site at the end of the genome.
Can a lambda vector be used for cloning?
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 …
Can a lambda vector be used in a petri dish?
Libraries constructed in lambda vectors are screened easily with antibody or nucleic acid probes since several thousand clones can be plated on a single petri dish.
How many KB of DNA can Lambda embl4 carry?
Lambda EMBL4 • It can carry up to 20 kb of inserted DNA by replacing a segment flanked by pairs of EcoRI, BamHI, and SalI sites. • Any of these three restriction endonucleases can be used to remove the stuffer fragment, so DNA fragments with a variety of sticky ends can be cloned.