PT - JOURNAL ARTICLE AU - Bennett, Malcolm J. AU - Marchant, Alan AU - Green, Haydn G. AU - May, Sean T. AU - Ward, Sally P. AU - Millner, Paul A. AU - Walker, Amanda R. AU - Schulz, Burkhard AU - Feldmann, Kenneth A. TI - <strong><em>Arabidopsis AUX1</em></strong> Gene: A Permease-Like Regulator of Root Gravitropism AID - 10.1126/science.273.5277.948 DP - 1996 Aug 16 TA - Science PG - 948--950 VI - 273 IP - 5277 4099 - http://science.sciencemag.org/content/273/5277/948.short 4100 - http://science.sciencemag.org/content/273/5277/948.full SO - Science1996 Aug 16; 273 AB - The plant hormone auxin regulates various developmental processes including root formation, vascular development, and gravitropism. Mutations within the AUX1 gene confer an auxin-resistant root growth phenotype and abolish root gravitropic curvature. Polypeptide sequence similarity to amino acid permeases suggests that AUX1 mediates the transport of an amino acid-like signaling molecule. Indole-3-acetic acid, the major form of auxin in higher plants, is structurally similar to tryptophan and is a likely substrate for the AUX1 gene product. The cloned AUX1 gene can restore the auxin-responsiveness of transgenic aux1 roots. Spatially, AUX1 is expressed in root apical tissues that regulate root gravitropic curvature.