[Progress on Sp1-like and Krüppel-like factors].

Sp1-like and Krüppel-like factors (Sp1/KLFs) are a family of zinc-finger proteins that are important components of transcriptional machinery in eukaryotic cells. Sp1/KLFs have highly conserved DNA binding domains at the carboxyl terminus that have three tandem zinc-finger motifs. Their amino terminal regions vary greatly and contain transcription regulatory domains that interact with co-regulators. By regulating the expression of a large number of genes containing GC-rich or CACCC promoters in a tissue-, cell- and developmental stage-specific manner, Sp1/KLFs may be involved in many biological processes, including cell proliferation, differentiation, apoptosis and neoplastic transformation. In this article, we reviewed the structure, molecular mechanisms and biological functions of Sp1/KLFs.