RetroSor1 is a LTR retrotransposon described from sequencing data in Sorghum bicolor (Llaca et al. 1998). This element belongs to a lineage of plant LTR retrotransposons (Tat), sibling of other lineage of putative plant endogenous retroviruses (Athila), providing evidence of a shared ancestral lineage originally described as class A by Wright and Voytas (1998). The genomic structure of RetroSor1 is 13.4 Kb in size including LTRs of 0.7 Kb. The internal region displays a Primer Binding Site (PBS) complementary to a tRNALys, a single Open Reading Frame (ORF) coding for a gag-pol polyprotein, a untranslated (UTR) region downstream to the integrase domain of approximately 6.4 Kb in size, and also, a Polypurine Tract (PPT) adjacent to the 3´LTR (Llaca et al. 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