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bioRxiv · 10.1101/111831

Subdomains of the Pol V largest subunit CTD mediate locus-specific RNA-directed DNA methylation

Wendte, J.·Haag, J.·Singh, J.·McKinlay, A.·Pontes, O.·Pikaard, C.
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Abstract

Plant multisubunit RNA Polymerase V transcription recruits Argonaute 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 carboxyl-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 locusspecific effects. In a yeast two-hybrid screen, the 3'->5' exoribonuclease, RRP6L1 was identified as an interactor with the DeCL subdomain and DeCL and glutamine-serine-rich (QS) subdomains, located downstream from an Argonaute-binding repeat 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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Wendte, J., Haag, J., Singh, J., McKinlay, A., Pontes, O., Pikaard, C.. 2017-02-25. Subdomains of the Pol V largest subunit CTD mediate locus-specific RNA-directed DNA methylation. https://doi.org/10.1101/111831

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