N-terminal domain of Kruppel-like factor (KLF) 8, KLF12, and similar proteins
Kruppel-like transcription factors (also known as Krueppel-like transcription factors, KLFs) belong to a family of proteins called the Specificity Protein (SP)/KLF family, characterized by a C-terminal DNA-binding domain of 81 amino acids consisting of three Kruppel-like C2H2 zinc fingers. These factors bind to a loose consensus motif, namely NNRCRCCYY (where N is any nucleotide; R is A/G, and Y is C/T), such as the recurring motifs in GC and GT boxes (5'-GGGGCGGGG-3' and 5-GGTGTGGGG-3') that are present in promoters and more distal regulatory elements of mammalian genes. Although these factors bind to similar elements in vitro, they have distinct activities in vivo depending on their expression profile and the sequence of the N-terminal activation/repression domain, which differ between members. This model represents the related N-terminal activation/repression domains of KLF8 and KLF12.