Gene trapping is a
high-throughput approach that is used to introduce insertional
mutations
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
across an organism's genome.
Method
Trapping is performed with gene trap vectors whose principal element is a gene trapping cassette consisting of a promoterless reporter gene and/or selectable
genetic marker, flanked by an upstream 3' splice site (splice acceptor; SA) and a downstream
transcription
Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including:
Genetics
* Transcription (biology), the copying of DNA into RNA, the fir ...
al termination sequence (
polyadenylation
Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In euk ...
sequence; polyA).
When inserted into an
intron
An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e. a region inside a gene."The notion of the cistron .e., gene. ...
of an expressed gene, the gene trap cassette is transcribed from the endogenous promoter of that gene in the form of a fusion transcript in which the exon(s) upstream of the insertion site is spliced in frame to the reporter/selectable marker gene. Since transcription is terminated prematurely at the inserted polyadenylation site, the processed fusion transcript encodes a truncated and nonfunctional version of the cellular
protein and the reporter/selectable marker. Thus, gene traps simultaneously inactivate and report the expression of the trapped gene at the insertion site, and provide a
DNA tag (gene trap sequence tag, GTST) for the rapid identification of the disrupted
gene.
Access
The International Gene Trap Consortium is centralizing the data and supplies modified cell lines.
References
Further reading
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External links
{{Scholia
Genetics