Nina Ripin, a German Masters student, was able to determine this structure with help from David Jacques and Mitchell Guss. analysis of the structure indicates that although the N-terminal ZF (NF) can modulate GATA1 DNA binding, the NF binds DNA so poorly under physiological conditionsthat it cannot play a direct role in DNA looping (a suggestion made recently). Rather, the ability of the NF to stabilise transcriptional complexes through protein-protein interactions, and thereby recruit looping factors such as Ldb1, seems a more likely model for GATA-mediated looping.
The Nucleosome Remodeling and Deacetylase (NuRD) complex is essential for the normal regulation of gene expression in a wide range of organisms (even plants!). We are slowly trying to build up a picture of how NuRD works at a mechanistic level. One of the NuRD components, CHD4, contains two PHD-type zinc-finger domains. In collaboration with Tanya Kutateladze from the University of Colorado at Denver, we have shown that one of these two PHD domains can recognize the N-terminal tail of histone H3 when specifically modified by trimethylation of K9 (a repressive mark). We have determined the structure of the PHD:H3 tail complex, showing how the methylated K9 is recognized (on the right of the pic).