RNA Polymerase IV Directs Silencing of Endogenous DNA

✍ Scribed by Herr, A. J.

• Book ID: 121726210
• Publisher: American Association for the Advancement of Science
• Year: 2005
• Tongue: English
• Weight: 277 KB
• Volume: 308
• Category: Article
• ISSN: 0036-8075
• DOI: 10.1126/science.1106910

✦ Synopsis

Plants encode subunits for a fourth RNA polymerase (Pol IV) in addition to the well-known DNA-dependent RNA polymerases I, II, and III. By mutation of the two largest subunits (NRPD1a and NRPD2), we show that Pol IV silences certain transposons and repetitive DNA in a short interfering RNA pathway involving RNA-dependent RNA polymerase 2 and Dicer-like 3. The existence of this distinct silencing polymerase may explain the paradoxical involvement of an RNA silencing pathway in maintenance of transcriptional silencing.