Abstract: Auxin response factors (ARFs), a family of transcription factors, have been discovered recently. The ARFs bind specifically to the auxin response elements (AuxREs) within promoters of primary auxin responsive genes and function as activators or repressors. The ARFs contain three domains, namely a conserved N-terminal DNA-binding domain, a non-conserved middle region, and a conserved C-terminal dimerization domain. The ARFs can form a protein complex with auxin/indoleacetic acid through homodimerization or heterodimerization. The particular protein-protein interaction may play a key role in modulating the expression of early auxin responsive genes. The identification of ARF mutations in Arabidopsis helps to demonstrate/dissect the function of ARFs in the normal growth and development of plants. Phylogenetic analysis also reveals some interesting protein evolution points in the ARF family.(Author for correspondence.Tel: +86(0)898 66890981; E-mail:mmpeng_2000@yahoo.com)

Key words: auxin/indoleacetic acid, auxin response elements, auxin response factors, auxin responsive genes.