Cer6 is a LTR retrotransposon described from sequencing data in the chromosome III of C. elegans (Bowen and McDonald 1999). Cer6 belongs, along with other LTR retrotransposons, to Mag a large Ty3/Gypsy cluster widely distributed in both protostomes and deuterostomes (for more details, see Malik and Eickbush 1999; Volff et al. 2001; Tubio, Naveira and Costas 2004). The genomic structure of Cer6 is 5.1 Kb in size including LTRs of 218 nt. The internal region of this element displays a Primer Binding Site (PBS) complementary to a tRNASer, a single Open Reading Frame (ORF) gag-pol displaying two frameshiftings (first, in the protease domain, and second, between the RNAseH and Integrase domains), 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