The Athb-1 and -2 HD-Zip domains homodimerize forming complexes of different DNA binding specificities.

摘要: The Arabidopsis Athb-1 and -2 proteins are characterized by the presence of a homeodomain (HD) with closely linked leucine zipper motif (Zip). We have suggested that HD-Zip could, via dimerization zippers, recognize dyad-symmetric DNA sequences. Here we report an analysis binding properties homeodomain-leucine (HD-Zip-1) domain in vitro. performed using random-sequence templates showed HD-Zip-1 domain, but not HD alone, binds to DNA. recognizes 9 bp sequence [CAAT(A/T)ATTG], as determined selecting high-affinity sites from Gel retardation assays demonstrated dimer. Moreover, activity derivatives indicated correct spatial relationship between Zip is essential for binding. Finally, Athb-2 distinct [CAAT(G/C)ATTG]. A model proposed.