'''Gene trapping''' is a [[High-throughput screening|high-throughput]] approach that is used to introduce insertional [[mutations]] across the [[mammalian]] genome. It 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 3’3' splice site (splice acceptor; SA) and a downstream [[transcription (genetics)|transcription]]al termination sequence (polyadenylation sequence; polyA). When inserted into an [[intron]] 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]].<ref>{{cite journal|first1=S|last1=De-Zolt|first2=F|last2= Schnutgen|display-authors=etal|date=2006|title=High-throughput trapping of secretory pathway genes in mouse embryonic stem cells|journal=Nucleic Acids Res|volume=34|issue=3|page=25}}</ref>
An international public consortium [http://www.genetrap.org/ International Gene Trap Consortium] is centralizing the data and cell lines can be requested from them.
