Cer3 is a LTR retrotransposon described from sequencing data in the chromosome IV of Caenorhabditis elegans (Bowen and McDonald 1999). Along with Cer2 this element constitutes Cer2-3 clade, a small clade of Ty3/Gypsy-like LTR retroelements. The genomic structure of Cer3 is 8.7 Kb in size including LTRs of 424 nt. The internal region of this element displays a Primer Binding Site (PBS) complementary to a tRNAGly, three Open Reading Frames (ORFs) for the gag-pro, pol, and int genes, and a Polypurine Tract (PPT) adjacent to the 3´LTR (Bowen and McDonald 1999; Ganko, Fielman and McDonald 2001).
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