Arabidopsis homolog of the yeast TREX-2 mRNA export complex: components and anchoring nucleoporin

Abstract

SUMMARYNuclear pore complexes (NPCs) are vital to nuclear-cytoplasmic communication in eukaryotes. The yeast NPCassociated TREX-2 complex, also known as the Thp1-Sac3-Cdc31-Sus1 complex, is anchored on the NPC via the nucleoporin Nup1, and is essential for mRNA export. Here we report the identification and characterization of the putative Arabidopsis thaliana TREX-2 complex and its anchoring nucleoporin. Physical and functional evidence support the identification of the Arabidopsis orthologs of yeast Thp1 and Nup1. Of three Arabidopsis homologs of yeast Sac3, two are putative TREX-2 components, but, surprisingly, none are required for mRNA export as they are in yeast. Physical association of the two Cdc31 homologs, but not the Sus1 homolog, with the TREX-2 complex was observed. In addition to identification of these TREX-2 components, direct interactions of the Arabidopsis homolog of DSS1, which is an established proteasome component in yeast and animals, with both the TREX-2 complex and the proteasome were observed. This suggests the possibility of a link between the two complexes. Thus this work has identified the putative Arabidopsis TREX-2 complex and provides a foundation for future studies of nuclear export in Arabidopsis.

HISTONE DEACETYLASE6 Interacts with FLOWERING LOCUS D and Regulates Flowering in Arabidopsis

“…Both HDA6 and FLD were fused to the N-terminal 174-amino acid portion of yellow fluorescent protein (YFP) in the pEarleyGate201 vector (pEarleyGate201-YN) as well as the C-terminal 66-amino acid portion of YFP in the pEarleyGate202 vector (pEarleyGate202-YC; Lu et al, 2010). The corresponding constructs were codelivered into protoplasts of Arabidopsis, and fluorescence was observed using a confocal microscope.…”

“…The PCR products were subcloned into the pENTR/SD/D-TOPO or pCR8/GW/TOPO vector and then recombined into the pEarleyGate201-YN and pEarleyGate202-YC vectors (Lu et al, 2010). The resulting constructs were used for transient assays by polyethylene glycol transfection of Arabidopsis protoplasts (Yoo et al, 2007).…”

Dynamics of the Plant Nuclear Envelope and Nuclear Pore

“…An FG-Nup identified both as Nup136 (Tamura et al, 2010) and as Nup1 (Lu et al, 2010) appears to be unique to plants. Its cell cycle dynamics include dispersal at metaphase, accumulation around the chromosomes in late anaphase/early telophase, and reestablishment at the NE in late telophase.…”

“…In yeast, a connection between the chromatin-bound Spt-Ada-Gcn5 acetyltransferase (SAGA) transcriptional coactivator complex, the nuclear pore protein Mlp1, and the RNA export complex TREX-2 (also known as the Thp1-Sac3-Cdc31-Sus1 complex) is implied in this activation. The SAGA histone acetyl transferase component Gcn5, the plant Mlp1 homolog NUA, and subunits of TREX-2 have all been identified in Arabidopsis, making it worthwhile to test if a similar connection might be involved in regulating plant gene expression (Stockinger et al, 2001;Xu et al, 2007b;Lu et al, 2010;Yelina et al, 2010). Nucleoporins are bound to hundreds of genomic sites, as identified by chromatin immunoprecipitation experiments and fusion of Nups to micrococcal nuclease (Schmid et al, 2006;Capelson et al, 2010;Vaquerizas et al, 2010;Wälde and Kehlenbach, 2010).…”

Retraction

“…Full-length coding sequences of FLS2, EFR, BAK1, CERK1, LTI6b, and IOS1 without stop codon amplified from cDNA of Arabidopsis Col-0 were inserted into the entry vector pCR8/GW/TOPO and subcloned into YN (pEarleyGate201-YN) or YC (pEarleyGate202-YC) vectors (Lu et al, 2010c) through LR reaction (Invitrogen). The constructs were transfected into Arabidopsis protoplasts by polyethylene glycol (Sigma-Aldrich) for transient expression (Yoo et al, 2007).…”