title: bZIP17 and bZIP60 Regulate the Expression of BiP3 and Other Salt Stress Responsive Genes in an UPR-Independent Manner in Arabidopsis thaliana.
abstract: Plants can be severely affected by salt stress. Since these are sessile organisms, they have developed different cellular responses to cope with this problem. Recently, it has been described that bZIP17 and bZIP60, two ER-located transcription factors, are involved in the cellular response to salt stress. On the other hand, bZIP60 is also involved in the unfolded protein response (UPR), a signaling pathway that up-regulates the expression of ER-chaperones. Coincidentally, salt stress produces the up-regulation of BiP, one of the main chaperones located in this organelle. Then, it has been proposed that UPR is associated to salt stress. Here, by using insertional mutant plants on bZIP17 and bZIP60, we show that bZIP17 regulate the accumulation of the transcript for the chaperone BiP3 under salt stress conditions, but does not lead to the accumulation of UPR-responding genes such as the chaperones Calnexin, Calreticulin, and PDIL under salt treatments. In contrast, DTT, a known inducer of UPR, leads to the up-regulation of all these chaperones. On the other hand, we found that bZIP60 regulates the expression of some bZIP17 target genes under conditions were splicing of bZIP60 does not occur, suggesting that the spliced and unspliced forms of bZIP60 play different roles in the physiological response of the plant. Our results indicate that the ER-located transcription factors bZIP17 and bZIP60 play a role in salt stress but this response goes through a signaling pathway that is different to that triggered by the unfolded protein response.
authors.affiliation: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Henriquez-Valencia
authors.affiliation: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Adrian A
authors.initials: AA
authors.lastname: Moreno
authors.affiliation: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Omar
authors.initials: O
authors.lastname: Sandoval-Ibañez
authors.affiliation: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Irina
authors.initials: I
authors.lastname: Mitina
authors.affiliation: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Francisca
authors.initials: F
authors.lastname: Blanco-Herrera
authors.affiliation: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Cifuentes-Esquivel
authors.affiliation: Centro de Biotecnología Vegetal, FONDAP Center for Genome Regulation, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Ariel
authors.initials: A
authors.lastname: Orellana
mesh_terms: D017398:Alternative Splicing; D017360:Arabidopsis / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics*; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics*; D004229:Dithiothreitol / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D018832:Molecular Chaperones / Q000235:genetics*; D054712:Salinity; D013312:Stress, Physiological; D056811:Unfolded Protein Response / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; C585260:BiP3 protein, Arabidopsis; D018832:Molecular Chaperones; C525259:bZIP17 protein, Arabidopsis; C533092:bZIP60 protein, Arabidopsis; D004229:Dithiothreitol
keywords: Arabidopsis thaliana; SALINITY STRESS; TRANSCRIPTION FACTOR; UPR; bZIP17; bZIP60