CFG1 is a Ty3/Gypsy LTR retrotransposon described in the genome of the mollusca Chlamys Farreri ( Wang et al 2007). Expression of CFG1 appears to be controlled by a post-transcriptional gene silencing mechanisms associated to reverse transcriptase (RT) methylation ( Wang et al 2007). CFG1 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 CFG1 is 4.7 Kb in size including LTRs of 192 and 189 nt. The internal region of this element displays a Primer Binding Site (PBS), a single Open Reading Frame (ORF) that codes for a single gag-pol polyprotein, and a Polypurine Tract (PPT) adjacent to the 3´LTR ( Wang et al 2007).
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
Mobile DNA II. (Craig et al. 2002)