Functional Dissection of the Pol V Largest Subunit CTD in RNA-Directed DNA Methylation

Autor: Jered M. Wendte, Jeremy R. Haag, Jasleen Singh, Anastasia McKinlay, Olga M. Pontes, Craig S. Pikaard
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Cell Reports, Vol 19, Iss 13, Pp 2796-2808 (2017)
Druh dokumentu: article
ISSN: 2211-1247
DOI: 10.1016/j.celrep.2017.05.091
Popis: Plant multisubunit RNA polymerase V (Pol V) transcription recruits Argonaute-small interfering RNA (siRNA) complexes that specify sites of RNA-directed DNA methylation (RdDM) for gene silencing. Pol V’s largest subunit, NRPE1, evolved from the largest subunit of Pol II but has a distinctive C-terminal domain (CTD). We show that the Pol V CTD is dispensable for catalytic activity in vitro yet essential in vivo. One CTD subdomain (DeCL) is required for Pol V function at virtually all loci. Other CTD subdomains have locus-specific effects. In a yeast two-hybrid screen, the 3′→ 5′ exoribonuclease RRP6L1 was identified as an interactor with the DeCL and glutamine-serine (QS)-rich subdomains located downstream of an Argonaute-binding subdomain. Experimental evidence indicates that RRP6L1 trims the 3′ ends of Pol V transcripts sliced by Argonaute 4 (AGO4), suggesting a model whereby the CTD enables the spatial and temporal coordination of AGO4 and RRP6L1 RNA processing activities.
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