RT Journal
A1 de Mendoza, Alex
A1 Pflueger, Jahnvi
A1 Lister, Ryan
T1 Capture of a functionally active methyl-CpG binding domain by an arthropod retrotransposon family
JF Genome Research 
JO Genome Research 
YR 2019 
FD August 01 
VO 29 
IS 8 
SP 1277 
OP 1286 
DO 10.1101/gr.243774.118 
UL http://genome.cshlp.org/content/29/8/1277.abstract 
AB The repressive capacity of cytosine DNA methylation is mediated by recruitment of silencing complexes by methyl-CpG binding domain (MBD) proteins. Despite MBD proteins being associated with silencing, we discovered that a family of arthropod Copia retrotransposons have incorporated a host-derived MBD. We functionally show how retrotransposon-encoded MBDs preferentially bind to CpG-dense methylated regions, which correspond to transposable element regions of the host genome, in the myriapod Strigamia maritima. Consistently, young MBD-encoding Copia retrotransposons (CopiaMBD) accumulate in regions with higher CpG densities than other LTR-retrotransposons also present in the genome. This would suggest that retrotransposons use MBDs to integrate into heterochromatic regions in Strigamia, avoiding potentially harmful insertions into host genes. In contrast, CopiaMBD insertions in the spider Stegodyphus dumicola genome disproportionately accumulate in methylated gene bodies compared with other spider LTR-retrotransposons. Given that transposons are not actively targeted by DNA methylation in the spider genome, this distribution bias would also support a role for MBDs in the integration process. Together, these data show that retrotransposons can co-opt host-derived epigenome readers, potentially harnessing the host epigenome landscape to advantageously tune the retrotransposition process.