KLF4

KLF4 also known as gut-enriched Kruppel-like factor (GKLF) acts as a transcriptional activator or repressor depending on the promoter context and/or cooperation with other transcription factors. It transactivates the iNOS promoter in cooperation with p65 and the p21Cip1/Waf1 promoter in cooperation with p53, but it directly suppresses the p53 promoter and inhibits ornithine decarboxylase promoter activity by competing with specificity protein-1 (Sp-1). Moreover interaction of KLF4 with the C-terminal domain of MUC1 enhances suppression of TP53/p53 transcription. It binds to the CACCC core sequence and to multiple sites in the 5'-flanking region of its own gene and can activate its own transcription. This nuclear protein belongs to the krueppel C2H2-type zinc-finger protein family with three C2H2-type zinc fingers. KLF4 also interacts with the p300/CBP transcription co-activators. It is up regulated in vascular injury and has been identified as an anti-proliferative shear stress-responsive gene. Forced over-expression of KLF4 in vascular smooth muscle cells induces growth arrest. With respect to embryonic stem cells KLF4 has been identified as one of the key regulators of dedifferentiation of the fully differentiated somatic cells to stem cells. KLF4 is also required for establishing the barrier function of the skin and for postnatal maturation and maintenance of the ocular surface. It is involved in the differentiation of epithelial cells and may also function in skeletal and kidney development.

IMGENEX Corporation as well as ImgenexIndia has thus come up with antibodies against various Kruppel-like factors and other transcription factors regulating the stem cell pathway and thus help researchers in modulating these for effective response in therapeutic purposes.