title: Constitutive expression of an endoplasmic reticulum small heat shock protein alleviates endoplasmic reticulum stress in transgenic tomato.
abstract: To explore the function of endoplasmic reticulum-located small heat-shock proteins (ER-sHSPs) in ER stress, a putative ER-sHSP cDNA (the driven protein was named as LeHSP21.5 with GenBank accession No. AB026983) was isolated from tomato (Lycopersicon esculentum). Fractionation of the crude microsomes by isopycnic sucrose-gradient centrifugation revealed that LeHSP21.5 was distributed on a density corresponding to the fractions with a higher activity of ER marker enzyme, suggesting the localization of LeHSP21.5 in the ER. Overexpressing LeHSP21.5 in transgenic tomato plants (L. esculentum var. Zhongshu 4) greatly attenuated the lethal effect of tunicamycin on tomato seedlings. Moreover, under the tunicamycin treatment, transcripts of BiP, PDI and calnexin in transgenic tomato plants accumulated to a less level than those in non-transgenic tomato plants. These results suggest that LeHSP21.5 can function to alleviate the tunicamycin-induced ER stress.
authors.affiliation: College of Life Science, Shandong Normal University, Jinan, Shandong, PR China.
authors.forename: Chunmei
authors.initials: C
authors.lastname: Zhao
authors.forename: Mariko
authors.initials: M
authors.lastname: Shono
authors.forename: Aiqing
authors.initials: A
authors.lastname: Sun
authors.forename: Shuying
authors.initials: S
authors.lastname: Yi
authors.forename: Minghui
authors.initials: M
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
mesh_terms: D003001:Cloning, Molecular; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D050888:Heat-Shock Proteins, Small / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D017510:Protein Folding; D012333:RNA, Messenger / Q000378:metabolism; D014415:Tunicamycin / Q000633:toxicity*
chemical_list: D050888:Heat-Shock Proteins, Small; D010940:Plant Proteins; D012333:RNA, Messenger; D014415:Tunicamycin