Ephrin A1 is a protein that in humans is encoded by the EFNA1 gene.   
This gene encodes a member of the
ephrin (EPH) family. The ephrins and EPH-related receptors comprise the largest subfamily of receptor protein-tyrosine kinases and have been implicated in mediating developmental events, especially in the nervous system and in erythropoiesis. Based on their structures and sequence relationships, ephrins are divided into the ephrin-A (EFNA) class, which are anchored to the membrane by a glycosylphosphatidylinositol linkage, and the ephrin-B (EFNB) class, which are transmembrane proteins. This gene encodes an EFNA class ephrin which binds to the EPHA2, EPHA4, EPHA5, EPHA6, and EPHA7 receptors. Two transcript variants that encode different isoforms were identified through sequence analysis. 
Model organisms [ edit ]
Model organisms have been used in the study of EFNA1 function. A conditional knockout mouse line, called Efna1 tm1a(EUCOMM)Wtsi  was generated as part of the  International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.   
Male and female animals underwent a standardized
phenotypic screen to determine the effects of deletion.  Twenty four tests were carried out on homozygous  mutant mice and one significant abnormality was observed: a transformation in vertebral number from lumbar vertebrae to sacral vertebrae. 
References [ edit ]
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^ a b "Entrez Gene: EFNA1 ephrin-A1".
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^ ". Wellcome Trust Sanger Institute. Salmonella infection data for Efna1"
^ ". Wellcome Trust Sanger Institute. Citrobacter infection data for Efna1"
^ a b c Gerdin AK (2010). "The Sanger Mouse Genetics Programme: High throughput characterisation of knockout mice". Acta Ophthalmologica. 88: 925–7. doi: 10.1111/j.1755-3768.2010.4142.x.
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^ Dolgin E (Jun 2011). "Mouse library set to be knockout". Nature. 474 (7351): 262–3. doi: 10.1038/474262a. PMID 21677718.
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Further reading [ edit ]
Pandey A, Lindberg RA, Dixit VM (Sep 1995). "Cell signalling. Receptor orphans find a family". Current Biology. 5 (9): 986–9. doi: 10.1016/S0960-9822(95)00195-3. PMID 8542290.
Flanagan JG, Vanderhaeghen P (1998). "The ephrins and Eph receptors in neural development". Annual Review of Neuroscience. 21: 309–45. doi: 10.1146/annurev.neuro.21.1.309. PMID 9530499.
Zhou R (Mar 1998). "The Eph family receptors and ligands". Pharmacology & Therapeutics. 77 (3): 151–81. doi: 10.1016/S0163-7258(97)00112-5. PMID 9576626.
Holder N, Klein R (May 1999). "Eph receptors and ephrins: effectors of morphogenesis". Development. 126 (10): 2033–44. PMID 10207129.
Wilkinson DG (2000). "Eph receptors and ephrins: regulators of guidance and assembly". International Review of Cytology. 196: 177–244. doi: 10.1016/S0074-7696(00)96005-4. PMID 10730216.
Xu Q, Mellitzer G, Wilkinson DG (Jul 2000). "Roles of Eph receptors and ephrins in segmental patterning". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 355 (1399): 993–1002. doi: 10.1098/rstb.2000.0635. PMC . 1692797 PMID 11128993.
Wilkinson DG (Mar 2001). "Multiple roles of EPH receptors and ephrins in neural development". Nature Reviews. Neuroscience. 2 (3): 155–64. doi: 10.1038/35058515. PMID 11256076.
Mahadevan D, Thanki N, Singh J, McPhie P, Zangrilli D, Wang LM, Guerrero C, LeVine H, Humblet C, Saldanha J (Jul 1995). "Structural studies on the PH domains of Db1, Sos1, IRS-1, and beta ARK1 and their differential binding to G beta gamma subunits". Biochemistry. 34 (28): 9111–7. doi: 10.1021/bi00028a021. PMID 7619809.
Kozlosky CJ, Maraskovsky E, McGrew JT, VandenBos T, Teepe M, Lyman SD, Srinivasan S, Fletcher FA, Gayle RB, Cerretti DP (Jan 1995). "Ligands for the receptor tyrosine kinases hek and elk: isolation of cDNAs encoding a family of proteins". Oncogene. 10 (2): 299–306. PMID 7838529.
Davis S, Gale NW, Aldrich TH, Maisonpierre PC, Lhotak V, Pawson T, Goldfarb M, Yancopoulos GD (Nov 1994). "Ligands for EPH-related receptor tyrosine kinases that require membrane attachment or clustering for activity". Science. 266 (5186): 816–9. doi: 10.1126/science.7973638. PMID 7973638.
Beckmann MP, Cerretti DP, Baum P, Vanden Bos T, James L, Farrah T, Kozlosky C, Hollingsworth T, Shilling H, Maraskovsky E (Aug 1994). "Molecular characterization of a family of ligands for eph-related tyrosine kinase receptors". The EMBO Journal. 13 (16): 3757–62. PMC . 395287 PMID 8070404.
Gale NW, Holland SJ, Valenzuela DM, Flenniken A, Pan L, Ryan TE, Henkemeyer M, Strebhardt K, Hirai H, Wilkinson DG, Pawson T, Davis S, Yancopoulos GD (Jul 1996). "Eph receptors and ligands comprise two major specificity subclasses and are reciprocally compartmentalized during embryogenesis". Neuron. 17 (1): 9–19. doi: 10.1016/S0896-6273(00)80276-7. PMID 8755474.
Ephnomenclaturecommittee (Aug 1997). "Unified nomenclature for Eph family receptors and their ligands, the ephrins. Eph Nomenclature Committee". Cell. 90 (3): 403–4. doi: 10.1016/S0092-8674(00)80500-0. PMID 9267020.
Nagel W, Schilcher P, Zeitlmann L, Kolanus W (Aug 1998). "The PH domain and the polybasic c domain of cytohesin-1 cooperate specifically in plasma membrane association and cellular function". Molecular Biology of the Cell. 9 (8): 1981–94. doi: 10.1091/mbc.9.8.1981. PMC . 25450 PMID 9693361.