Transposable elements (TEs) promote various chromosomal rearrangements more efficiently, and often more specifically, thanother cellular processes. Retrotransposons are structurally similar to retroviruses and are bounded by long terminal repeats. This entry represents eukaryotic Gag or capsid-related retrotranspon-related proteins, including Retrotransposon-derived protein PEG10 from Mus musculus, which binds its own mRNA and self-assembles into virion-like capsids [, ]. There is a central motif QGXXEXXXXXFXXLXXH that is common to Retroviridae gag-proteins, but is poorly conserved [].