AP2 (APETALA2) and EREBPs (ethylene-responsive element binding proteins) are the prototypic members of a family of transcription factors unique to plants, whose distinguishing characteristic is that they contain the so-called AP2 DNA-binding domain. AP2/ REBP genes form a large multigene family, and they play a variety of roles throughout the plant life cycle: from being key regulators of several developmental processes, like floral organ identity determination or control of leaf epidermal cell identity, to forming part of the mechanisms used by plants to respond to various types of biotic and environmental stress.These proteins contain either one (EREBP subfamily) or two (AP2 subfamily) copies of an approximately 70 amino acid domain termed the AP2 repeat because of its initial description in the floral homeotic protein APETALA2 (AP2). In proteins containing a single AP2 repeat, this region has been shown to exhibit DNA binding activity. Proteins that have a single AP2 repeat include EREBPs/ethylene response factors (ERFs), C-repeat/dehydration response element binding proteins (CBFs/DREBs), ABI4 and TINY. Proteins containing two AP2 repeats include AP2, ANT and the products of the maize indeterminate spikelet1 (ids1) and Glossy15 (Gl15) genes.DNA binding specificity has been determined for three types of AP2/EREBP proteins that contain a single AP2 repeat. The first class are proteins which bind to ethylene response elements (ERE) or GCC boxes (tobacco EREBPs, Arabidopsis AtEBP and AtERF1-5, and tomato Pti4-6) found in the promoters of ethylene-inducible pathogenesis related genes .The second class includes proteins that bind to the C-repeat or dehydration response element (DRE) in the promoters of genes that are turned on in response to low temperatures and/or water deficit (CBF1, CBF2, CBF3/DREB1A and DREB2A). The C-repeat/DREs contain the core sequence CCGAC (19).The third class of AP2/EREBP-like proteins that have been shown to bind DNA consists of Arabidopsis RAV1 and RAV2. RAV1 and RAV2 are highly related proteins that contain two DNA binding motifs: a single AP2 repeat and a B3-like domain Using an in vitro selection procedure, the DNA binding specificity of the two AP2 repeat containing protein ANT was found to be 5'-gCAC(A/G)N(A/T)TcCC(a/g)ANG(c/t)-3'. This consensus site is much longer than sites recognized by proteins containing a single AP2 repeat and neither AP2 repeat of ANT was alone capable of binding to the selected sequences, suggesting that both AP2 repeats make DNA contacts.