Retrovirus Silencing by an Epigenetic TRIM

Retrovirus Silencing by an Epigenetic TRIM

Embryonic cells silence transcription by retroviruses, but how do they recognize virus DNA? In this issue, Wolf and Goff (2007) report that a TRIM28 corepressor complex binds to the retrovirus primer binding site. Epigenetic silencing of retrovirus transcription is accomplished by "writing" a dimethyl mark on lysine 9 of histone H3 that is read by the heterochromatin protein HP1gamma.

Epigenetic gene silencing in cancer.

Synthetic reversal of epigenetic silencing.

Controlling cell fate-determining gene expression is key to stem cell differentiation, tissue regeneration, and cancer therapy. To date, custom-built transcription factors recognize the information encoded in specific DNA sequences. Chromatin proteins undergo covalent modifications and form complexes that encode a second layer of information that determines proximal gene activity. Here, we empl...

Inheritance of epigenetic chromatin silencing.

Maintenance of alternative chromatin states through cell divisions pose some fundamental constraints on the dynamics of histone modifications. In this paper, we study the systems biology of epigenetic inheritance by defining and analyzing general classes of mathematical models. We discuss how the number of modification states involved plays an essential role in the stability of epigenetic state...

Epigenetic silencing in transgenic plants

Epigenetic silencing is a natural phenomenon in which the expression of genes is regulated through modifications of DNA, RNA, or histone proteins. It is a mechanism for defending host genomes against the effects of transposable elements and viral infection, and acts as a modulator of expression of duplicated gene family members and as a silencer of transgenes. A major breakthrough in understand...