Long 5' leaders of many auxin response factor (ARF) mRNAs harbor multiple uORFs. Rectangles represent uORFs that are in frame (red) with the main ORF, in the -1 position (green), or in the +1 position (blue). Start codon contexts are illustrated as weak (O, NNNAUGN), moderate (#, RNNAUGN or NNNAUGG) and strong (&, RNNAUGG). The cDNA sequences shown generally correspond to the longest known gene model displayed at http://www.arabidopsis.org/ in November 2009: ARF2 (AT5G62000.1); ARF3 (AT2G33860.1); ARF4 (AT5G60450.1); ARF5 (AT1G19850.1); ARF6 (AT1G30330.1); ARF7 (AT5G20730.1); ARF11 (AT2G46530.1). A splice variant known for ARF2 retains uORF1 and uORF3 (intron flanked by black triangles).