Kaiso uses all three zinc fingers and adjacent sequence motifs for high affinity binding to sequence-specific and methyl-CpG DNA targets

Abstract

Kaiso is a Cys2His2 zinc finger (ZF) protein that mediates methyl-CpG-dependent and sequence-specific transcriptional repression. As a first step towards elucidating the structural and molecular basis for recognition of these disparate DNA sequences, the minimal binding region of Kaiso was identified and optimal DNA sequences for high-affinity interactions were characterized. Contrary to previous findings, Kaiso requires all three zinc fingers plus adjacent protein regions for DNA recognition. An N-terminal extension contributes to structural stability, while an extended C-terminal region augments DNA binding. Complexes formed between the optimized Kaiso construct and both DNA sequences are suitable for future structural evaluation.