The human AF10 gene has been associated with chromosomal translocation in acute leukemias. In the March 15 EMBO Reports, Linder et al. describe their study of the Drosophila AF10 homolog, dAF10, in an attempt to understand its function (EMBO Reports 2001, 2:211-216). They isolated the dAF10 gene from a database screen and show that it codes for four transcripts that are differentially expressed during fly embryogenesis. The dAF10 protein contains a PLVVL pentamer motif that mediates interaction with the fly heterochromatin protein 1 (HP1), which is encoded by the Su(var)2-5 gene. Linder et al. characterized mutations of the dAF10 gene to demonstrate that dAF10 is a functional repressor component of heterochromatin and that the gene genetically interacts with Su(var)2-5 in suppression of position effect variegation (PEV).