Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2000
Publication Date: N/A
Citation: N/A Interpretive Summary: The ability of a plant to respond to environmental stress is a major factor in agricultural productivity. When subjected to an abrupt elevation in temperature, plants respond by switching off normal housekeeping activities and switching on production of the elements of the stress response. Genetic material that contains information necessary for production of one important stress response element was isolated from the model plant thale cress, and studied. Comparisons were made with similar genetic material from animals and microbes in order to predict regions of particular importance. Environmental conditions that result in activation of this genetic material were defined. This information will be important to researchers in their attempts to increase agricultural productivity by altering the ability of plants to respond to environmental stress, and to other plant scientists who will try to design more efficient crop plants through either classical breeding or biotechnology.
Technical Abstract: An Arabidopsis thaliana cDNA encoding a protein related to YdJ1p of Saccharomyces cerevisiae was sequenced. Primers based upon the cDNA sequence were used to isolate the corresponding gene, ATJ3. The structure of this gene consists of six exons interrupted by five introns. The results of Southern analysis are consistent with the existence of a single ATJ3 gene. Translation of ATJ3 yields a protein closely related to YdJ1p. The J-, G/F, and zinc-finger domains characteristic of this class of DnaJ homologues are all present in the AtJ3 sequence, as is the C-terminal -Caax farnesylation motif. The results of Northern analysis indicate that ATJ3 is constitutively expressed in all organs; cotyledons, leaves, roots, flowers, and siliques. The results of Western analyses of total proteins from the same organs showed less variation in AtJ3 protein levels than in the mRNA. A 35 degree heat shock led to a five-fold increase in mRNA expression in leaves, but only a doubling in the protein level.