Chimera (EST)

In genetics, a chimera is a single cDNA sequence originating from two transcripts. It is usually considered to be a contaminant in transcript and expressed sequence tag (EST) databases.^[1] It is estimated that approximately 1% of all transcripts in the National Center for Biotechnology Information's Unigene database contain a "chimeric sequence".^[2]

Methods have been devised to detect them, such as the Ribosomal Database Project's CHECK_CHIMERA program.^[3] However, in protein engineering, "chimeragenesis (forming chimeras between proteins that are encoded by homologous cDNAs)"^[4] is one of the "two major techniques used to manipulate cDNA sequences".^[4]

Examples

• "The first mRNA transcript isolated for..." the human gene C2orf3 "...was part of an artificial chimera..."
• CYP2C17 was thought to be a human gene, but "...is now considered an artefact based on a chimera of CYP2C18 and CYP2C19."^[5]
• Researchers have created receptor chimeras in their studies of Oncostatin M.

See also

• Ribosome
• Transgene

References

1. Unneberg, P; Claverie, JM; Hoheisel, Jörg (2007). Hoheisel, Jörg, ed. "Tentative Mapping of Transcription-Induced Interchromosomal Interaction using Chimeric EST and mRNA Data". PLoS ONE 2 (2): e254. doi:10.1371/journal.pone.0000254. PMC 1804257. PMID 17330142.
2. Charlie Nelson. "EST Assembly for the Creation of Oligonucleotide Probe Targets" (PDF). Agilent Technologies. Retrieved May 12, 2009.
3. Maidak, B. (1996). "The Ribosomal Database Project (RDP)". Nucleic Acids Research 24 (1): 82. doi:10.1093/nar/24.1.82. Retrieved May 12, 2009.
4. Lajtha, Abel; E. A. Reith, Maarten (2007). Handbook of Neurochemistry and Molecular Neurobiology Neural Membranes and Transport. Boston, MA: Springer Science+Business Media, LLC. p. 485. ISBN 0-387-30347-2. p. 424
5. "Entrez Gene: CYP2C18 cytochrome P450, family 2, subfamily C, polypeptide 18". National Center for Biotechnology Information. Retrieved May 12, 2009.