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Highly Accessed Open Badges Protein family review

Sp1- and Krüppel-like transcription factors

Joanna Kaczynski12, Tiffany Cook4 and Raul Urrutia123*

Author Affiliations

1 Gastroenterology Research Unit, Mayo Clinic, Rochester, MN 55901, USA

2 Tumor Biology Program, Mayo Clinic, Rochester, MN 55901, USA

3 Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55901, USA

4 Department of Biology, New York University, New York, NY 10003, USA

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Genome Biology 2003, 4:206  doi:10.1186/gb-2003-4-2-206

Published: 3 February 2003


Sp1-like proteins and Krüppel-like factors (KLFs) are highly related zinc-finger proteins that are important components of the eukaryotic cellular transcriptional machinery. By regulating the expression of a large number of genes that have GC-rich promoters, Sp1-like/KLF transcription regulators may take part in virtually all facets of cellular function, including cell proliferation, apoptosis, differentiation, and neoplastic transformation. Individual members of the Sp1-like/KLF family can function as activators or repressors depending on which promoter they bind and the coregulators with which they interact. A long-standing research aim has been to define the mechanisms by which Sp1-like factors and KLFs regulate gene expression and cellular function in a cell- and promoter-specific manner. Most members of this family have been identified in mammals, with at least 21 Sp1-like/KLF proteins encoded in the human genome, and members are also found in frogs, worms and flies. Sp1-like/KLF proteins have highly conserved carboxy-terminal zinc-finger domains that function in DNA binding. The amino terminus, containing the transcription activation domain, can vary significantly between family members.