title: Characterization of a Novel DWD protein that participates in heat stress response in Arabidopsis.
abstract: Cullin4-RING ubiquitin ligase (CRL4) is a family of multi-subunit E3 ligases. To investigate the possible involvement of CRL4 in heat stress response, we screened T-DNA insertion mutants of putative CRL4 substrate receptors that exhibited altered patterns in response to heat stress. One of the mutants exhibited heat stress tolerance and was named heat stress tolerant DWD1 (htd1). Introduction of HTD1 gene into htd1-1 led to recovery of heat sensitivity to the wild type level, confirming that the decrease of HTD1 transcripts resulted in heat tolerance. Therefore, HTD1 plays a negative role in thermotolerance in Arabidopsis. Additionally, HTD1 directly interacted with DDB1a in yeast two-hybrid assays and associated with DDB1b in vivo, supporting that it could be a part of a CRL4 complex. Various heat-inducible genes such as HSP14.7, HSP21, At2g03020 and WRKY28 were hyper-induced in htd1-1, indicating that HTD1 could function as a negative regulator for the expression of such genes and that these genes might contribute to thermotolerance of htd1-1, at least in part. HTD1 was associated with HSP90-1, a crucial regulator of thermotolerance, in vivo, even though the decrease of HTD1 did not affect the accumulation pattern of HSP90-1 in Arabidopsis. These findings indicate that a negative role of HTD1 in thermotolerance might be achieved through its association with HSP90-1, possibly by disturbing the action of HSP90-1, not by the degradation of HSP90-1. This study will serve as an important step toward understanding of the functional connection between CRL4-mediated processes and plant heat stress signaling.
authors.affiliation: Department of Biology Education, Pusan National University, Busan 609-735, Korea.
authors.forename: Soon-Hee
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Biology Education, Pusan National University, Busan 609-735, Korea.
authors.forename: Joon-Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Biology Education, Pusan National University, Busan 609-735, Korea ; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA.
authors.forename: Kyoung-In
authors.initials: KI
authors.lastname: Seo
authors.affiliation: Department of Biology Education, Pusan National University, Busan 609-735, Korea.
authors.forename: Boyeong
authors.initials: B
authors.lastname: Ryu
authors.affiliation: Department of Biology Education, Pusan National University, Busan 609-735, Korea.
authors.forename: Yongju
authors.initials: Y
authors.lastname: Sung
authors.affiliation: Department of Biological Sciences, Pusan National University, Busan 609-735, Korea.
authors.forename: Taijoon
authors.initials: T
authors.lastname: Chung
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA.
authors.forename: Xing Wang
authors.initials: XW
authors.lastname: Deng
authors.affiliation: Department of Biology Education, Pusan National University, Busan 609-735, Korea ; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA.
authors.forename: Jae-Hoon
authors.initials: JH
authors.lastname: Lee
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial; D018506:Gene Expression Regulation, Plant; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response; D016254:Mutagenesis, Insertional; D015398:Signal Transduction; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D018841:HSP90 Heat-Shock Proteins; C000599720:HTD1 protein, Arabidopsis; C466978:Hsp90-1 protein, Arabidopsis; C036483:T-DNA; D044767:Ubiquitin-Protein Ligases
keywords: Arabidopsis; CRL4; HSP; HTD1; heat stress