Nomad is a retrovirus characterized in Drosophila melanogaster (Whalen and Grigliatti 1998) and 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 Nomad is 7.6 Kb in size including LTRs of 0.5 Kb. The internal region displays a Primer Binding Site complementary to a tRNALys, three Open Reading Frames (ORFs) for gag, pol, and env genes, and a Polypurine Tract (PPT) adjacent to the 3´LTR, The host-DNA "TANA" sequence, appears to be duplicated in each terminal end of Nomad, and seems to be the main insertion target of this element (Whalen and Grigliatti 1998).
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