Arabidopsis tRNA ligase completes the cytoplasmic splicing of bZIP60 mRNA in the unfolded protein response

Nagashima, Yukihiro; Iwata, Yuji; Mishiba, Kei‐ichiro; Koizumi, Nozomu

doi:10.1016/j.bbrc.2016.01.145

Cited by 26 publications

(27 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pAtRNL::cAtRNL‐sYFP construct used carries the claimed both first and second translation initiation sites. Consistent with our observations, another biochemical analysis also showed that AtRNL is localized primarily in the soluble fraction of the cell extracts (Nagashima et al ). In addition, transgenic expression of the claimed shorter version of cAtRNL under the control of the CaMV 35S promoter is effective and sufficient to complement the zyg3 mutant (Nagashima et al ).…”

Section: Discussionsupporting

confidence: 92%

“…Consistent with our observations, another biochemical analysis also showed that AtRNL is localized primarily in the soluble fraction of the cell extracts (Nagashima et al ). In addition, transgenic expression of the claimed shorter version of cAtRNL under the control of the CaMV 35S promoter is effective and sufficient to complement the zyg3 mutant (Nagashima et al ). We therefore suggest that the unexpected localizations observed by Englert et al () may have been caused by over‐accumulation of GFP when expressed under the control of CaMV 35S promoter.…”

Section: Discussionsupporting

confidence: 92%

“…This may involve translation of both maternal‐delivered and zygotic‐expressed mRNA. In addition to its function in tRNA splicing, AtRNL may also function in other cellular processes such as RNA repair (Amitsur et al ; Schwer et al ; Nandakumar et al ; Chan et al ) and non‐spliceosomal splicing of mRNA (Sidrauski et al ; Mori et al ; Nagashima et al ). With data provided, we cannot exclude the possibility that AtRNL may play other roles beyond tRNA splicing during embryogenesis.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

ZYGOTE‐ARREST 3 that encodes the tRNA ligase is essential for zygote division in Arabidopsis

Yang

Guo

Hou

et al. 2017

JIPB

View full text Add to dashboard Cite

In sexual organisms, division of the zygote initiates a new life cycle. Although several genes involved in zygote division are known in plants, how the zygote is activated to start embryogenesis has remained elusive. Here, we showed that a mutation in ZYGOTE-ARREST 3 (ZYG3) in Arabidopsis led to a tight zygote-lethal phenotype. Map-based cloning revealed that ZYG3 encodes the transfer RNA (tRNA) ligase AtRNL, which is a single-copy gene in the Arabidopsis genome. Expression analyses showed that AtRNL is expressed throughout zygotic embryogenesis, and in meristematic tissues. Using pAtRNL::cAtRNL-sYFPcomplemented zyg3/zyg3 plants, we showed that AtRNL is localized exclusively in the cytoplasm, suggesting that tRNA splicing occurs primarily in the cytoplasm. Analyses using partially rescued embryos showed that mutation in AtRNL compromised splicing of intron-containing tRNA. Mutations of two tRNA endonuclease genes, SEN1 and SEN2, also led to a zygote-lethal phenotype. These results together suggest that tRNA splicing is critical for initiating zygote division in Arabidopsis.

show abstract

Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

ZYGOTE‐ARREST 3 that encodes the tRNA ligase is essential for zygote division in Arabidopsis

Yang

Guo

Hou

et al. 2017

JIPB

View full text Add to dashboard Cite

show abstract

“…In Arabidopsis ( Arabidopsis thaliana ), two basic leucine zipper (bZIP) transcription factors, bZIP60 and bZIP28, have been known to induce ER chaperone gene expression (Angelos, Ruberti, Kim, & Brandizzi, ; Howell, ; Iwata & Koizumi, ). bZIP60 is activated by cytoplasmic splicing through the ER membrane‐localized kinase/ribonuclease IRE1 and the tRNA ligase Rlg1(Deng et al., ; Nagashima, Iwata, Mishiba, & Koizumi, ; Nagashima et al., ). bZIP28 is an ER membrane‐bound transcription factor that is activated by proteolysis within its transmembrane domain by the Golgi‐localized metalloprotease site‐2 protease (S2P) (Iwata et al., ; Srivastava, Chen, Deng, Brandizzi, & Howell, ).…”

Section: Introductionmentioning

confidence: 99%

Constitutive BiP protein accumulation in Arabidopsis mutants defective in a gene encoding chloroplast‐resident stearoyl‐acyl carrier protein desaturase

et al. 2018

Self Cite

View full text Add to dashboard Cite

The unfolded protein response (UPR) occurs when protein folding and maturation are disturbed in the endoplasmic reticulum (ER). During the UPR, a number of genes including those encoding ER-resident molecular chaperones are induced. In Arabidopsis, BiP3 has been used as a UPR marker gene whose expression is strongly induced in response to ER stress. In this study, we mutagenized Arabidopsis plants expressing β-glucuronidase (GUS) gene under the control of BiP3 promoter and isolated a mutant that exhibits strong GUS activity without treatment with ER stress inducers. By whole genome sequencing, we identified a causal gene in the mutant as SUPPRESSOR OF SALICYLIC ACID INSENSITIVITY2 (SSI2), which encodes stearoyl-acyl carrier protein desaturase that converts stearic acids to oleic acids in the chloroplasts. In addition to GUS proteins, the ssi2 mutant accumulates endogenous BiP3 proteins without treatment by any stress reagents. Interestingly, although the degree of endogenous BiP3 protein accumulation in the ssi2 mutant was comparable to that in wild-type plants treated with the ER stress inducer tunicamycin, much less BiP3 transcripts were detected in the ssi2 mutant compared to tunicamycin-treated wild-type plants. Our finding suggests a genetic link between fatty acid metabolism in the chloroplasts and ER functions.

show abstract

“…Upon IRE1A or/and IRE1B activation by ER stress, a 23-bp fragment of bZIP60 U is spliced out to generate the spliced bZIP60 (bZIP60 S)142628. The cleaved 5′ and 3′ fragments can be rejoined in vitro by the Arabidopsis tRNA ligase RLG129. The bZIP60 S protein differs in bZIP60 U by lacking the single transmembrane domain (TMD) and thus becomes an active transcription factor that up-regulates the UPR target genes142628.…”

mentioning

confidence: 99%

Divergence and Conservation of the Major UPR Branch IRE1-bZIP Signaling Pathway across Eukaryotes

Zhang

Wang

2016

Sci Rep

View full text Add to dashboard Cite

The unfolded protein response (UPR) is crucial to life by regulating the cellular response to the stress in the endoplasmic reticulum (ER) imposed by abiotic and biotic cues such as heat shock and viral infection. The inositol requiring enzyme 1 (IRE1) signaling pathway activated by the IRE1-mediated unconventional splicing of HAC1 in yeast, bZIP60 in plants and XBP1 in metazoans, is the most ancient branch of the UPR. In this study, we systematically examined yeast IRE1p-HAC1, plant IRE1A/IRE1B-bZIP60 and human hIRE1-XBP1 pairs. We found that, unlike bZIP60, XBP1 is unable to functionally swap HAC1p in yeast, and that the inter-species heterotypic interactions among HAC1p, bZIP60 and XBP1 are not permitted. These data demonstrate evolutionary divergence of the downstream signaling of IRE1-bZIP. We also discovered that the dual cytosolic domains of plant IRE1s act in vivo in a mechanism consistent with IRE1p and hIRE1, and that plant IRE1B not only interacts with IRE1p but also forms typical IRE1 dynamic foci in yeast. Thus, the upstream components of the IRE1 signaling branch including IRE1 activation and action mechanisms are highly conserved. Taken together these data advance the molecular understanding of evolutionary divergence and conservation of the IRE1 signaling pathway across kingdoms.

show abstract

Arabidopsis tRNA ligase completes the cytoplasmic splicing of bZIP60 mRNA in the unfolded protein response

Cited by 26 publications

References 27 publications

ZYGOTE‐ARREST 3 that encodes the tRNA ligase is essential for zygote division in Arabidopsis

ZYGOTE‐ARREST 3 that encodes the tRNA ligase is essential for zygote division in Arabidopsis

Constitutive BiP protein accumulation in Arabidopsis mutants defective in a gene encoding chloroplast‐resident stearoyl‐acyl carrier protein desaturase

Divergence and Conservation of the Major UPR Branch IRE1-bZIP Signaling Pathway across Eukaryotes

Contact Info

Product

Resources

About