Reiterated WG/GW motifs form functionally and evolutionarily conserved ARGONAUTE-binding platforms in RNAi-related components.

Mahmoud El-Shami (1) , Dominique Pontier (1) , Sylvie Lahmy (1) , Laurence Braun (2) , Claire Picart (1) , Danielle Vega (1) , Mohamed-Ali Hakimi (2) , Steven E Jacobsen (3) , Richard Cooke (1) , Thierry Lagrange (1)

1 LGDP - Laboratoire Génome et développement des plantes
2 LAPM - Laboratoire Adaptation et pathogénie des micro-organismes [Grenoble]
3 Department of Molecular, Cell and Developmental Biology

Two forms of RNA Polymerase IV (PolIVa/PolIVb) have been implicated in RNA-directed DNA methylation (RdDM) in Arabidopsis. Prevailing models imply a distinct function for PolIVb by association of Argonaute4 (AGO4) with the C-terminal domain (CTD) of its largest subunit NRPD1b. Here we show that the extended CTD of NRPD1b-type proteins exhibits conserved Argonaute-binding capacity through a WG/GW-rich region that functionally distinguishes Pol IVb from Pol IVa, and that is essential for RdDM. Site-specific mutagenesis and domain-swapping experiments between AtNRPD1b and the human protein GW182 demonstrated that reiterated WG/GW motifs form evolutionarily and functionally conserved Argonaute-binding platforms in RNA interference (RNAi)-related components.

Domaines: Biochimie, Biologie Moléculaire

Mahmoud El-Shami, Dominique Pontier, Sylvie Lahmy, Laurence Braun, Claire Picart, et al.. Reiterated WG/GW motifs form functionally and evolutionarily conserved ARGONAUTE-binding platforms in RNAi-related components.. Genes and Development, 2007, 21 (20), pp.2539-44. ⟨10.1101/gad.451207⟩. ⟨hal-00198842⟩