CHRFAM7A explained

CHRNA7-FAM7A fusion protein is a protein that in humans is encoded by the CHRFAM7A gene.^{[1] [2]}

The nicotinic acetylcholine receptors (nAChRs) are members of a superfamily of ligand-gated ion channels that mediate fast signal transmission at synapses. The family member CHRNA7, which is located on chromosome 15 in a region associated with several neuropsychiatric disorders, is partially duplicated and forms a hybrid with a novel gene from the family with sequence similarity 7 (FAM7A). Alternative splicing has been observed, and two variants exist, for this hybrid gene. The N-terminally truncated products predicted by the largest open reading frames for each variant would lack the majority of the neurotransmitter-gated ion-channel ligand binding domain but retain the transmembrane region that forms the ion channel. Although current evidence supports transcription of this hybrid gene, translation of the nicotinic acetylcholine receptor-like protein-encoding open reading frames has not been confirmed.CHRFAM7A has not been found in nonhuman primates, and its occurrence in individuals of African descent is significantly lower than in Caucasian populations.^[3]

Further reading

• Gault J . Genomic organization and partial duplication of the human alpha7 neuronal nicotinic acetylcholine receptor gene (CHRNA7) . Genomics . 52 . 2 . 173–85 . 1998 . 9782083 . 10.1006/geno.1998.5363 . Robinson M . Berger R . 3 . Drebing . Carla . Logel . Judith . Hopkins . Jan . Moore . Ted . Jacobs . Suzette . Meriwether . Jennifer .
• Freedman R . Linkage disequilibrium for schizophrenia at the chromosome 15q13-14 locus of the alpha7-nicotinic acetylcholine receptor subunit gene (CHRNA7) . Am. J. Med. Genet. . 105 . 1 . 20–2 . 2001 . 11424985 . 10.1002/1096-8628(20010108)105:1<20::AID-AJMG1047>3.0.CO;2-C . Leonard S . Gault JM . 3 . Hopkins . Jan . Cloninger . C. Robert . Kaufmann . Charles A. . Tsuang . Ming T. . Farone . Stephen V. . Malaspina . Dolores . 37412240 .
• Strausberg RL . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . Feingold EA . Grouse LH . 3 . Derge . JG . Klausner . RD . Collins . FS . Wagner . L . Shenmen . CM . Schuler . GD . 2002PNAS...9916899M . free .
• Trombino S . Alpha7-nicotinic acetylcholine receptors affect growth regulation of human mesothelioma cells: role of mitogen-activated protein kinase pathway . Cancer Res. . 64 . 1 . 135–45 . 2004 . 14729617 . 10.1158/0008-5472.CAN-03-1672 . Cesario A . Margaritora S . 3 . Granone . P . Motta . G . Falugi . C . Russo . P . free .
• Gerhard DS . The Status, Quality, and Expansion of the NIH Full-Length cDNA Project: The Mammalian Gene Collection (MGC) . Genome Res. . 14 . 10B . 2121–7 . 2004 . 15489334 . 10.1101/gr.2596504 . 528928 . Wagner L . Feingold EA . 3 . Shenmen . CM . Grouse . LH . Schuler . G . Klein . SL . Old . S . Rasooly . R .
• Bale AS . Volatile organic compounds inhibit human and rat neuronal nicotinic acetylcholine receptors expressed in Xenopus oocytes . Toxicol. Appl. Pharmacol. . 205 . 1 . 77–88 . 2005 . 15885267 . 10.1016/j.taap.2004.09.011 . Meacham CA . Benignus VA . 3 . Bushnell . Philip J. . Shafer . Timothy J. .
• Freedman R . Characterization of allelic variants at chromosome 15q14 in schizophrenia . . 5 . 14–22 . 2006 . 16417613 . 10.1111/j.1601-183X.2006.00190.x . Leonard S . Waldo M . 3 . Gault . J. . Olincy . A. . Adler . L. E. . Suppl 1 . free.
• Zody MC . Analysis of the DNA sequence and duplication history of human chromosome 15 . Nature . 440 . 7084 . 671–5 . 2006 . 16572171 . 10.1038/nature04601 . Garber M . Sharpe T . 3 . Young . Sarah K. . Rowen . Lee . O'Neill . Keith . Whittaker . Charles A. . Kamal . Michael . Chang . Jean L. . 2006Natur.440..671Z . free .
• Dempster EL . Episodic memory performance predicted by the 2bp deletion in exon 6 of the "alpha 7-like" nicotinic receptor subunit gene . The American Journal of Psychiatry . 163 . 10 . 1832–4 . 2006 . 17012698 . 10.1176/appi.ajp.163.10.1832 . Toulopoulou T . McDonald C . 3 . Bramon . E. . Walshe . M. . Wickham . H. . Sham . P. C. . Murray . R. M. . Collier . D. A. .
• Martin LF . Sensory Gating and Alpha-7 Nicotinic Receptor Gene Allelic Variants in Schizoaffective Disorder, Bipolar Type . Am. J. Med. Genet. B Neuropsychiatr. Genet. . 144 . 5 . 611–4 . 2007 . 17192894 . 10.1002/ajmg.b.30470 . Leonard S . Hall MH . 3 . Tregellas . Jason R. . Freedman . Robert . Olincy . Ann . 3123155 .

Notes and References

1. Riley B, Williamson M, Collier D, Wilkie H, Makoff A . A 3-Mb map of a large Segmental duplication overlapping the alpha7-nicotinic acetylcholine receptor gene (CHRNA7) at human 15q13-q14 . Genomics . 79 . 2 . 197–209 . Feb 2002 . 11829490 . 10.1006/geno.2002.6694 .
2. Web site: Entrez Gene: CHRFAM7A CHRNA7 (cholinergic receptor, nicotinic, alpha 7, exons 5-10) and FAM7A (family with sequence similarity 7A, exons A-E) fusion.
3. Szafranski. Przemyslaw. Schaaf. Christian P.. Person. Richard E.. Gibson. Ian B.. Xia. Zhilian. Mahadevan. Sangeetha. Wiszniewska. Joanna. Bacino. Carlos A.. Lalani. Seema. 2010-07-01. Structures and Molecular Mechanisms for Common 15q13.3 Microduplications Involving CHRNA7: Benign or Pathological?. Human Mutation. 31. 7. 840–850. 10.1002/humu.21284. 1059-7794. 3162316. 20506139.