The threshold induction temperature of the 90-kDa heat shock protein is subject to acclimatization in eurythermal goby fishes (genus Gillichthys).

Abstract

Two extremely eurythermal goby fishes, Gillichthys mirabilis and Giffichthys seta, which encounter habitat temperature variations of "30"C, showed seasonal matization of endogenous levels and of onset temperatures for enhanced synthesis of a 90-kDa-class heat shock protein (HSP90). Summer-acclimatized fishes had higher levels of HSP90 in brain tissue than winter-acclimatized specimens, as shown by Western blot analysis. For winter-acclimatized fishes, increased synthesis of HSP90 was observed when the temperature was raised from a control temperature (18C) to 28WC. For summer-acclimatized fish, no significantly increased synthesis of HSP90 occurred until the experimental temperature was raised to 32C. These data suggest that the threshold temperature at which enhanced expression of HSP-encoding genes occurs is not hard-wired genetically but may be subject to acclimatization. A causal relationship between seasonal changes in steady-state levels of HSP90 and the threshold temperature for enhanced HSP90 synthesis is discussed in terms of existing models for the regulation of HSP gene expression.Temperature regulation of gene expression is certain to be critical for the survival and success of ectothermic ("coldblooded") animals living in variable thermal environments. Presently, however, little is known about the interactions between temperature and gene regulation in eukaryotic organisms. The only well-understood example of temperature control of gene expression is that of the heat shock proteins (HSPs), a group of proteins whose synthesis can be induced by increases in temperature and by exposure to a variety of other stresses (e.g., heavy metals and alcohols). In addition to being stress-inducible, HSPs (or their cognates) exist as normal cellular constituents. The HSPs and their cognates have been implicated in various roles, from assisting in protein folding and oligomerization to steroid receptor activation and inactivation (1, 2). Both the HSPs and the heat shock response are highly conserved among phylogenetically divergent organisms (3), which attests to the critical' roles these molecules play in cellular function and adaptation.HSPs may play a role in physiological adaptation to environmental temperature change (e.g., during seasonal or diurnal shifts in ambient temperature). A clear relationship exists between different species' normal body temperatures and the temperatures at which HSP synthesis is induced; in the species so studied, HSP induction occurs at temperatures 5-10°C above normal body temperature (3), with some exceptions (4). Thermal induction may involve either the expression of a type of HSP not previously expressed or the enhanced expression of a class of HSP already present in the cell at some constitutive level. The correlation between normal body (cell) temperature and HSP induction temperature suggests that the HSP gene regulatory processes of different species have different set points (temperature thresholds) for heat-triggered induction of enhanced HSP production. However, ...

The 60-kDa Heat Shock Protein (HSP60) of the Sea Anemone Anemonia viridis: A Potential Early Warning System for Environmental Changes

“…Hofmann and Somero (1995) showed seasonal patterns of HSP70 and ubiquitin expression for acclimatization in the mussel Mytilus edulis. Additional examples of seasonal expression of HSPs are known from other organisms (Dietz and Somero, 1992). However, to the best of our knowledge, this is the first report of seasonal expression of HSPs in benthic marine Anthozoans.…”

Induction of the 72-kilodalton heat shock protein and protection from ultraviolet B–induced cell death in human keratinocytes by repetitive exposure to heat shock or 15-deoxy-Δ12,14-prostaglandin J2

“…This is of particular interest in dermatology where the inducer could be used topically and should not lose its effect upon repeated application. Adaptation to the set point of the heat shock response has been described in yeast and fish, and in a Drosophila model the expression of a transgene under control of the hsp70 promoter is reduced after repeated heat shocks (Dietz and Somero 1992;Hunt et al 1992;Carratu et al 1996). Very little information is available about the consequences of repeated stress exposure in mammalian cells.…”

Thermal tolerance of the crab Pachygrapsus marmoratus: intraspecific differences at a physiological (CTMax) and molecular level (Hsp70)

“…Studies in several populations and species have shown that there is a great variation in HSP expression patterns, mainly in three types of categories: as a function of thermal history, correlating to microhabitat, and between species . These types of studies have been performed in several marine organisms such as fish (e.g., Dietz and Somero 1992;Norris and Hightower 2002;Buckley and Hofmann 2002;Fangue et al 2006), bivalves (e.g., Chapple et al 1998;Buckley et al 2001;Helmuth and Hofmann 2001;Encomio and Chu 2005), snails (e.g., Somero 1999, 2002;Tomanek and Sanford 2003;Clark and Peck 2009), and crustaceans (e.g., Botton et al 2006;Kelley et al 2011). Since most of the studies on intraspecific differences in thermal tolerance focus on latitudinal, intertidal distribution, and seasonal comparisons (see Hofmann 1999), it is important to approach intraspecific differences that have been less explored in marine organisms, especially sex and size differences.…”