Abstract
When organisms subjected to heat stress, patterns of gene expression change in a cell. Exclusive synthesis of heat shock proteins (HSPs) mRNAs occurs and these HSP mRNAs are efficiently translated while translation of existing normal cellular mRNAs is suppressed. It has been reported the 5' untranslated region (5'-UTR) of mRNA of HSP gene plays an important role in the efficient translation during heat stress. We report possibility that the expression of Arabidopsis thaliana HSP gene, HSP18.2, was also regulated at translational level under heat stress condition. We show translation was not suppressed during heat stress when the 5'-UTR sequence of HSP18.2 was inserted at upstream of initiation codon of β-glucuronidase gene in A. thaliana T87 protoplasts, Nicotiana tabacum BY-2 protoplasts and stable transgenic BY-2 clones. We also show that the secondary structure of 5'-UTR of HSP18.2 was unchanged by heat treatment in vitro.
