This group of TF was first described in Drosophila. These groups of proteins have CXC motifs with consensus sequence of CXCX4CX3YCXCX6CX3CXCX2C. This CXC domain, act as a zinc binding domain. Usually in this group of TFs two CXC domains are present, in plant proteins CXC domains are separated by variable length containing the short conserved sequence RNPXAFXPK.
1. S. U. Andersen, R. G. Algreen-Petersen, M. Hoedl, A. Jurkiewicz, C. Cvitanich, U. Braunschweig, L. Schauser, S. A. Oh, D. Twell, E. O. Jensen, The conserved cysteine-rich domain of a tesmin/TSO1-like protein binds zinc in vitro and TSO1 is required for both male and female fertility in Arabidopsis thaliana. J Exp Bot 58, 3657 (2007).