Difference between revisions of "Help:Tag"
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==Degradation Tags== | ==Degradation Tags== | ||
| − | These genetic tags mark a protein for degradation, thus decreasing a protein's half life (see each tag's specifications for their respective half lives). | + | These genetic tags mark a protein for degradation, thus decreasing a protein's half-life (see each tag's specifications for their respective half-lives). |
One of the useful aspects of genetic tags is the ability to detect gene activity in a time-sensitive manner. | One of the useful aspects of genetic tags is the ability to detect gene activity in a time-sensitive manner. | ||
Tags can be found on: | Tags can be found on: | ||
* [[Image:Part icon reporter.png]][https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=reporter Reporters], | * [[Image:Part icon reporter.png]][https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=reporter Reporters], | ||
| − | * [[Image:Part icon cds.png]][https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=coding Protein | + | * [[Image:Part icon cds.png]][https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=coding Protein-coding parts], |
* [[Image:Part icon generator.png]][https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=generator Protein Generators], and | * [[Image:Part icon generator.png]][https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=generator Protein Generators], and | ||
* [[Image:Part icon inverter.png]][https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=inverter Inverters].<br> | * [[Image:Part icon inverter.png]][https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=inverter Inverters].<br> | ||
| − | ''Note'': Tags cannot currently be used as [[An Introduction to BioBricks| | + | ''Note'': Tags cannot currently be used separately as [[An Introduction to BioBricks|BioBricks]] because currently all of our [https://parts.igem.org/cgi/partsdb/pgroup.cgi?pgroup=Coding Protein-coding parts] end in the double stop codon "<b>TAATAA</b>". |
===Mechanism of Use=== | ===Mechanism of Use=== | ||
Revision as of 21:05, 4 May 2007
Browse Tag parts!
Contents
Introduction to Tags
(Degradation) tags are genetic additions to the end of a sequence that modify expressed proteins in different ways such as marking the protein for faster degradation (see below).
Tags are also used for binding various particles in solution (making them easier to purify in solution from other proteins in a cell). Famous examples of the latter are the [http://en.wikipedia.org/wiki/His-tag "His tag"] (which binds to Nickel or Cobalt) and the [http://www-users.med.cornell.edu/~jawagne/FLAG-tag.html "FLAG tag"] (which binds to an "AntiFLAG" antibody), both of which are commercially available.
Degradation Tags
These genetic tags mark a protein for degradation, thus decreasing a protein's half-life (see each tag's specifications for their respective half-lives). One of the useful aspects of genetic tags is the ability to detect gene activity in a time-sensitive manner.
Tags can be found on:
Note: Tags cannot currently be used separately as BioBricks because currently all of our Protein-coding parts end in the double stop codon "TAATAA".
Mechanism of Use
Currently all of our Tags operate through the use of protein-degrading enzymes (proteases) within the cell. They do so by coding for a sequence of about eleven amino acids at the C-terminus of a protein. This sequence is read by a special type of RNA known as ssRA ("small stable RNA A"), and then degraded by the proteases ClpXP or ClpAP in e.coli (no such system is yet known for yeast).
Although originally the number of amino acids encoding for a ssRA tag was eleven (the first sequence that encoded for destruction via ssRA tagging was AANDENYALAA by [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8584937 Keiler et al]), a subsequent study by [http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=9603842 Andersen et al] tested the efficacy of mutating only the last three amino acids of that system. Thus our tags (AAV, ASV, LVA, LAA) are classified by only three amino acids.
Future Plans
Our future plans for tags involve building proteins using biobricks. To read more on this project, visit Ira Phillip's work on biobrick modification.
References
- Jabri and Nature News. "Tag, you're degraded". 2003. [http://www.nature.com/nsmb/journal/v10/n9/full/nsb0903-676.html article]
- Karzai, AW. "The SsrA−SmpB system for protein tagging, directed degradation and ribosome rescue". 2000. [http://www.nature.com/nsmb/journal/v7/n6/full/nsb0600_449.html Review Article]
- Keiler, KC et al. "Role of a peptide tagging system in degradation of proteins synthesized from damaged messenger RNA." 1996. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8584937 Pubmed]
- Andersen, JB et al. "New Unstable Variants of Green Fluorescent Protein for Studies of Transient Gene Expression in Bacteria". 1998. [http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=9603842 link]