Bacteriophage lambda: Difference between revisions
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== Morphology == | == Morphology == | ||
The λ phage has an icosahedral head about 50 nm in diameter, and a flexible tail about 150nm long.<ref name='LIB:Lambda_II'/> | The λ phage has an icosahedral head about 50 nm in diameter, and a flexible tail about 150nm long.<ref name='LIB:Lambda_II'/> The head contains a single double-stranded DNA molecule about 48 kb in length; by weight the genome is about 32x10<sup>6</sup> Da and comprises about half of the phage's weight.<ref name='LIB:Lambda_II'/> The DNA is linear when packaged, and recircularizes at the ''cos'' ('''co'''hesive end '''s'''ite) once injected into the host. <ref name='LIB:Lambda_II'/> | ||
== Genome Organization == | |||
== | == Life Cycle == | ||
=== Lytic Cycle === | |||
The lytic cycle is the usual life cycle, and results in the death of the host bacteria. | |||
==== Adsorbtion and Injection ==== | ==== Adsorbtion and Injection ==== | ||
The tip of the phage tail ([[Phage_lambda_J:Gene_Product(s)|J protein]]) attaches to the host cell protein [[lamB]], which is displayed on the outer membrane.<ref name='LIB:Lambda_II'/> The dsDNA is injected through the tail as a linear genome, when the phage tail interacts with the inner membrane protein [[ptsM]] and recircularizes once inside the host due to complementary 12nt long sticky ends. <ref name='LIB:Lambda_II'/> | |||
==== Early gene | ==== Early Gene Expression ==== | ||
The cro gene is an immediate-early gene product.<ref name='LIB:BofV'/> | |||
CII and CIII are delayed-early gene products. <ref name='LIB:BofV'/> | |||
==== Middle Gene Expression ==== | |||
==== | ==== DNA Replication ==== | ||
==== Late | ==== Late Gene Expression ==== | ||
==== Packaging ==== | ==== Packaging ==== | ||
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==== Lysis ==== | ==== Lysis ==== | ||
=== Lysogenic | === Lysogenic State === | ||
The lysogenic lifecycle is the result of integration of the λ DNA into the host genome, and does not result in the death of the host cell. The λ DNA/host DNA unit is termed a prophage. | |||
=== Lysis-Lysogeny | The lysogenic state is the | ||
=== Lysis-Lysogeny Switch === | |||
=== Prophage | === Prophage Induction === | ||
== See also == | == See also == | ||
*[http://ecoliwiki.net/colipedia/index.php/Category:Gene_List:Phage_lambda| Lambda Gene List] | |||
*[http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=10710&lvl=3&lin=f&keep=1&srchmode=1&unlock Enterobacteriophage lambda at the NCBI taxonomy browser] | *[http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=10710&lvl=3&lin=f&keep=1&srchmode=1&unlock Enterobacteriophage lambda at the NCBI taxonomy browser] | ||
*[[wikipedia: Lambda_phage]] | *[[wikipedia: Lambda_phage]] | ||
Revision as of 22:11, 2 August 2011
Bacteriophage λ is the archetype of the lambdoid, or lambda-like phage, a subclass of the siphoviridae. λ is a temperate phage.
Morphology
The λ phage has an icosahedral head about 50 nm in diameter, and a flexible tail about 150nm long.[1] The head contains a single double-stranded DNA molecule about 48 kb in length; by weight the genome is about 32x106 Da and comprises about half of the phage's weight.[1] The DNA is linear when packaged, and recircularizes at the cos (cohesive end site) once injected into the host. [1]
Genome Organization
Life Cycle
Lytic Cycle
The lytic cycle is the usual life cycle, and results in the death of the host bacteria.
Adsorbtion and Injection
The tip of the phage tail (J protein) attaches to the host cell protein lamB, which is displayed on the outer membrane.[1] The dsDNA is injected through the tail as a linear genome, when the phage tail interacts with the inner membrane protein ptsM and recircularizes once inside the host due to complementary 12nt long sticky ends. [1]
Early Gene Expression
The cro gene is an immediate-early gene product.[2] CII and CIII are delayed-early gene products. [2]
Middle Gene Expression
DNA Replication
Late Gene Expression
Packaging
Lysis
Lysogenic State
The lysogenic lifecycle is the result of integration of the λ DNA into the host genome, and does not result in the death of the host cell. The λ DNA/host DNA unit is termed a prophage. The lysogenic state is the
Lysis-Lysogeny Switch
Prophage Induction
See also
- Lambda Gene List
- Enterobacteriophage lambda at the NCBI taxonomy browser
- wikipedia: Lambda_phage
- ICTVdb entry
- Siphoviridae at MicrobeWiki
- Phage lambda on UniProt
References
See Help:References for how to manage references in EcoliWiki.