Idefix is a retrovirus originally characterized from a strain of Drosophila melanogaster called RevI where Idefix and Zam (other Gypsy element) have been associated with a series of mutations affecting eye coloration (Desset et al. 1999). Idefix is primarily found in the centromeric heterochromatin but a limited number of Idefix copies are also found in the euchromatin (Conte et al. 2000). Idefix belongs to the genus Errantiviridae (Boeke et al. 1999; Pringle 1998; 1999; Hull 1999), a lineage of fly-retroviruses and LTR retrotransposons phylogenetically related to 412/mdg1 clade (Tubio, Naveira and Costas 2005). The genomic structure of Idefix is 7.4 Kb in size including LTRs of 0.6 Kb. The internal region displays a Primer Binding Site (PBS) complementary to a tRNALys-4, three Open Reading Frames (ORFs) for gag, pol, and env genes, and a Polypurine Tract (PPT) adjacent to the 3´LTR (Desset et al. 1999).
Figure not to scale. If present, long terminal repeats (LTRs) have been highlighted in blue. Amino acid motifs noted with lines indicate the conserved residues in each protein domain, abbreviations below mean:
||DU or DUT=dUTPase
||TAV or IBMP=transactivator/viroplasmin or inclusion body matrix protein
||PBS=primer binding site
||ATF=aphid transmission factor
||VAP=virion associated protein