FIGURE 4.

There are three models of paramutation: (A) RNA model, in which paramutagenic repeats of DNA are transcribed into dsRNA under the action of RdRP, which subsequently transformed into siRNA by a Dicer-like protein. Methylation of siRNA occurs via RdDM, which causes chromatin silencing of paramutable repeats by the addition of silencing complex inside enhancer complex resulted in the occurrence of paramutation. (B) Physical interaction, in which both paramutable and paramutagenic repeats physically interact by pairing protein complex and paramutation occurs epigenetically. (C) RNA-physical interaction, which is a combination of both abovementioned models, in which paramutable and paramutagenic repeats transcribed by RaRP into dsRNA, which are subsequently transformed into siRNA by a Dicer-like protein, and only cause chromatin silencing of paramutagenic sequence by RdDM. Subsequently, physical interaction is established via siRNA and pairing protein complex resulted in the modification of paramutable repeats.