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Updated: Jul 11, 2026

Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains
Published on: March 25, 2015
Zinc finger domain of Snail functions as a nuclear localization signal for importin beta-mediated nuclear import
Hideki Yamasaki1, Toshihiro Sekimoto, Tadashi Ohkubo
1Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8520, Japan.
Abstract:
Snail, a DNA-binding zinc finger protein, functions as a transcriptional repressor for genes including E-cadherin during development and the acquisition of tumor cell invasiveness. Human Snail is a 264-amino acid nuclear protein with an amino-terminal basic amino acid-rich domain (SNAG domain) and a carboxyl-terminal DNA-binding domain (zinc finger domain). A series of fusion proteins composed of green fluorescent protein (GFP) and portions of the Snail protein were generated, and their subcellular localization was examined. Fusion of the four zinc fingers to GFP led to the targeting of GFP to the nucleus, demonstrating that the zinc finger domain is sufficient for nuclear localization. Using an in vitro transport system, the nuclear import of Snail was reconstituted by importin (karyopherin) beta in the presence of Ran and NTF2. We further demonstrated that Snail binds directly to importin beta in a zinc finger domain-dependent manner. These results indicate that zinc finger domain of Snail functions as a nuclear localization signal and Snail can be transported into the nucleus in an importin beta-mediated manner.
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