title: Glutathione S-transferase interacting with far-red insensitive 219 is involved in phytochrome A-mediated signaling in Arabidopsis.
abstract: Far-red (FR) insensitive 219 (FIN219) was previously shown to be involved in phytochrome A-mediated FR light signaling. To further understand its function and regulatory relation with other light-signaling components, a yeast two-hybrid approach was used to isolate FIN219-interacting partners. Here, we demonstrate that FIN219-interacting protein 1 (FIP1) interacts with FIN219 in vitro and in vivo and is composed of 217 amino acids that belong to the tau class of the large glutathione S-transferase gene family. FIP1 was further shown to have glutathione S-transferase activity. The gain of function and partial loss of function of FIP1 resulted in a hyposensitive hypocotyl phenotype under continuous FR (cFR) light and a delayed flowering phenotype under long-day conditions, which suggests that FIP1 may exist in a complex to function in the regulation of Arabidopsis (Arabidopsis thaliana) development. In addition, FIP1 mRNA was down-regulated in the suppressor of phytochrome A-105 1 mutant and differentially expressed in constitutive photomorphogenic 1-4 (cop1-4) and cop1-5 mutants under cFR. Intriguingly, FIP1 expression was up-regulated in the fin219 mutant under all light conditions, except cFR. Furthermore, promoter activity assays revealed that FIP1 expression was light dependent, mainly associated with vascular tissues, and developmentally regulated. Subcellular localization studies revealed that the beta-glucuronidase-FIP1 fusion protein was localized in the nucleus and cytoplasm. Taken together, these data indicate that FIP1 may interact with FIN219 to regulate cell elongation and flowering in response to light.
authors.affiliation: Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei 106, Taiwan.
authors.forename: Ing-Chien
authors.initials: IC
authors.lastname: Chen
authors.forename: I-Ching
authors.initials: IC
authors.lastname: Huang
authors.forename: Ming-Jung
authors.initials: MJ
authors.lastname: Liu
authors.forename: Zhi-Gong
authors.initials: ZG
authors.lastname: Wang
authors.forename: Shu-Shiang
authors.initials: SS
authors.lastname: Chung
authors.forename: Hsu-Liang
authors.initials: HL
authors.lastname: Hsieh
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D002352:Carrier Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D035264:Flowers / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000032:analysis; D005982:Glutathione Transferase / Q000378:metabolism* / Q000502:physiology; D008027:Light; D008969:Molecular Sequence Data; D051942:Phytochrome A / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000032:analysis; D016415:Sequence Alignment; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques; D010453:Peptide Synthases
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D005966:Glucuronidase; D005982:Glutathione Transferase; D051942:Phytochrome A; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C412831:AT2G46370 protein, Arabidopsis; D010453:Peptide Synthases; C521252:FIN219-interacting protein 1, Arabidopsis; C497973:PHYA protein, Arabidopsis