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).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.