The lambda phage is a model organism studied in biology laboratories.
Classification of the lambda phage
The lambda phage is a virus which belongs to the Siphoviridaefamily. It infects the bacterium which is widely used in the laboratory, Escherichia coli.
Characteristics of the lambda phage
The lambda phage has a 48,500 base pair, linear, double-stranded DNA genome which has been entirely sequenced. It has the typical shape of a bacteriophage, a head in which the DNA is encapsulated and a tail and fibrils which enable it to attach itself and insert its DNA into the cell.
It can be involved in two different cycles:
- the lytic cycle, in which the infected bacterium dies and releases a large number of new virions, synthesised as a result of expression of the viral genes, which particularly leads to the production of capsid proteins ;
- the lysogen cycle, in which the viral genome is incorporated into the bacterial genome (as a prophage) and where the latency genes are expressed.
Use of the lambda phage in the laboratory
The lambda phage is studied to improve our understanding of host-virus relationships and also as a cloning vector.
The lambda phage is a bacteriophage with a head, tail and fibrils. © adenosine, Wikimedia, CC by-sa 3.0