Fig. 2

Different ways how TEs can affect gene expression. a Regulation in cis. The TE brings a ready-to-use regulatory sequence that carries a transcription factor binding site. The transcription factor can bind on this site and influence expression of the neighboring gene. b Regulation via piRNAs. In the nuclear silencing situation, a TE is present close to the gene of interest. The piRNA, via the Piwi protein, triggers histone modifications that silence the TE but also affect the RNA polymerase binding region of the neighboring gene. Because of the epigenetic modification of the TE, the gene expression is reduced. In the cytoplasm silencing situation, a TE-derived sequence is present in the 5’UTR of the gene. piRNAs specific to this TE bind the transcript in the cytoplasm via an Argonaute protein and trigger the degradation of the transcript