Constitutive expression of an endoplasmic reticulum small heat shock protein alleviates endoplasmic reticulum stress in transgenic tomato

J Plant Physiol. 2007 Jul;164(7):835-41. doi: 10.1016/j.jplph.2006.06.004. Epub 2006 Aug 10.

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.

MeSH terms

  • Cloning, Molecular
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / metabolism
  • Endoplasmic Reticulum / physiology*
  • Heat-Shock Proteins, Small / genetics
  • Heat-Shock Proteins, Small / metabolism
  • Heat-Shock Proteins, Small / physiology*
  • Lycopersicon esculentum / drug effects
  • Lycopersicon esculentum / genetics*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plant Proteins / physiology*
  • Plants, Genetically Modified / drug effects
  • Plants, Genetically Modified / physiology*
  • Plants, Genetically Modified / ultrastructure
  • Protein Folding
  • RNA, Messenger / metabolism
  • Tunicamycin / toxicity*

Substances

  • Heat-Shock Proteins, Small
  • Plant Proteins
  • RNA, Messenger
  • Tunicamycin