This gene encodes a CSL zinc finger-containing protein that is required for dipthamide biosynthesis. The encoded protein is necessary for the initial step in the modification of a histidine residue in elongation factor-2 to diphthamide. This modified residue is a target for ADP ribosylation by the bacterial toxins diphtheria toxin and Pseudomonas exotoxin A. Alternative splicing results in multiple transcript variants that encode the same isoform. [provided by RefSeq, Feb 2009].