Diffuse Decapping Enzyme DCP2 Accumulates in DCP1 Foci Under Heat Stress in Arabidopsis thaliana

Abstract

The decapping enzymes DCP1 and DCP2 are components of a decapping complex that degrades mRNAs. DCP2 is the catalytic core and DCP1 is an auxiliary subunit. It has been assumed that DCP1 and DCP2 are consistently co-localized in cytoplasmic RNA granules called processing bodies (P-bodies). However, it has not been confirmed whether DCP1 and DCP2 co-localize in Arabidopsis thaliana. In this study, we generated DCP1-green fluorescent protein (GFP) and DCP2-GFP transgenic plants that complemented dcp1 and dcp2 mutants, respectively, to see whether localization of DCP2 is identical to that of DCP1. DCP2 was present throughout the cytoplasm, whereas DCP1 formed P-body-like foci. Use of DCP1-GFP/DCP2-red fluorescent protein (RFP) or DCP1-RFP/DCP2-GFP plants showed that heat treatment induced DCP2 assembly into DCP1 foci. In contrast, cold treatment did not induce DCP2 assembly, while the number of DCP1 foci increased. These changes in DCP1 and DCP2 localization during heat and cold treatments occurred without changes in DCP1 and DCP2 protein abundance. Our results show that DCP1 and DCP2 respond differently to environmental changes, indicating that P-bodies have diverse DCP1 and DCP2 proportions depending on environmental conditions. The localization changes of DCP1 and DCP2 may explain how specific mRNAs are degraded during changes in environmental conditions.

The LSM1-7 Complex Differentially Regulates Arabidopsis Tolerance to Abiotic Stress Conditions by Promoting Selective mRNA Decapping

“…After cycloheximide treatment, which causes loss of P-bodies (Sheth and Parker, 2003), no cytoplasmic foci were observed in any case, suggesting that the detected LSM1-GFP spots indeed corresponded to P-bodies (Figures 1C; Supplemental Figure 2B). The identity of these foci was confirmed by colocalization studies with DCP1, a protein that accumulates in P-bodies (Xu et al, 2006;Weber et al, 2008;Motomura et al, 2015). The examination of LSM1A PRO -LSM1A-GFP and LSM1B PRO -LSM1B-GFP plants cotransformed with a 35S-RFP-DCP1 fusion (Perea-Resa et al, 2012) demonstrated that, in fact, LSM1A-GFP and LSM1B-GFP colocalized with RFP-DCP1 in root cells exposed to 4°C ( Figure 1D).…”

“…Remarkably, however, Arabidopsis LSM1 proteins were found to localize to P-bodies in response to the different stresses assayed, indicating that the molecular mechanisms mediating LSM1 localization to these foci do not depend on protein levels. In this way, DCP1 has also been reported to localize to P-bodies under stress conditions even though its levels do not increase (Motomura et al, 2015). These findings suggest that the localization of LSM1 to P-bodies, like that of DCP1 and other Arabidopsis RNA decayrelated proteins (Merret et al, 2013;Motomura et al, 2015), is induced in plants exposed to abiotic stresses.…”

“…In this way, DCP1 has also been reported to localize to P-bodies under stress conditions even though its levels do not increase (Motomura et al, 2015). These findings suggest that the localization of LSM1 to P-bodies, like that of DCP1 and other Arabidopsis RNA decayrelated proteins (Merret et al, 2013;Motomura et al, 2015), is induced in plants exposed to abiotic stresses. Moreover, our results show that LSM1 proteins are required for P-body formation under challenging situations, indicating that the assembly of these foci is also promoted by adverse environmental conditions.…”

Polysomes, Stress Granules, and Processing Bodies: A Dynamic Triumvirate Controlling Cytoplasmic mRNA Fate and Function

“…All three proteins are considered core decapping complex factors, indispensable for mRNA decapping and essential for postembryonic development (Xu and Chua, 2011). Colocalization of AtDCP1 and AtDCP2 in macromolecular foci detectable by confocal microscopy is dynamically regulated by heat stress (Motomura et al, 2015). Based on mutant analyses, the factor VCS regulates seed dormancy and germination in Arabidopsis (Basbouss-Serhal et al, 2017) and functions in plant-fungal pathogen interactions in Nicotiana benthamiana (Petre et al, 2016).…”

Tudor Staphylococcal Nuclease plays two antagonistic roles in RNA metabolism under stress

“…11,12 Second, treatment with cycloheximide, which causes trapping of mRNA in polysomes by inhibiting the translocation step during the elongation phase in protein synthesis, abolished SG and PB assembly. 11,13 By performing a co-localization study using SG-and PB-associated proteins eIF4e and DCP1, respectively, we have revealed that these RNP complexes are situated in close proximity to each other in Arabidopsis root cells under heat stress (Fig. 1, arrowheads).…”