Changes in ubiquitin conjugates and Hsp72 levels during arm regeneration in echinoderms

All organisms show a common defensive mechanism that results in the express ion of conserved heat shock proteins (Hsps). These proteins function in a w ide range of stressful conditions. We have monitored their levels in specie s of regenerating echinoderms with different mechanisms of regeneration and from different geographical locations. The effect of an artificial higher temperature on expression of Hsps was also studied. Two stress proteins (Hs p72 and ubiquitin) that are important in processes such as development and protein degradation were investigated. Using Western blot analysis and immu nocytochemistry, we found significant changes in the level (Hsp72) and patt ern of conjugation (ubiquitin) that corresponded with the repair phase (ear ly regenerative stages) and with the later growth and regeneration of new t issues. Animals from the intertidal environment showed a distinctly sustain ed expression pattern of Hsp72 compared with benthic animals which suggests a functionally adaptative and dynamic stress response program.