Search

We report in the present paper that proteins which react with a polyclonal antibody (pAb) raised against the heat-shock protein chaperonin60 (cpn60) were revealed by indirect immunofluorescence in the nucleus of a fish (fathead minnow, Pimephales promelas) cell line after heat-shock. This immunoreactive cpn60 associated with the nucleolus and with discrete foci. An increased abundance of two nuclear proteins of approx. 57 and 42 kDa, present in approximately equal amounts, was detected by Western blotting using an anti-cpn60 pAb as a probe during the same time period that cpn60 was revealed in the nucleus. These proteins also reacted with a monoclonal antibody (mAb) against human cpn60 but did not react with an mAb against the cytoplasmic chaperonin, TCP1. The kinetics of translocation and pattern of nuclear localization of this immunoreactive cpn60 differed from that of stress70, another major family of heatshock proteins. We suggest that these nuclear immunoreactive cpn60 proteins are members of the cpn60 family and that they play a chaperone role in folding and assembly of proteins in the nucleus which is distinct from that of stress70.

Stress proteins have been shown to provide information on the biological impact of toxic chemicals to organisms and to predict adverse consequences of that exposure. In this study we have examined the accumulation to two major stress proteins, hsp60 and hsp70, in banked samples to determine if they accumulate at high levels in organisms exposed to contaminants in their environment. We found that relative to laboratory controls, stress proteins concentrations were elevated in mussels and fish tissue collected as part of the NOAA National Status and Trends Program. Sediment and water chemistry from the stations where these organisms were collected and data on contaminant body burdens of these same organisms indicated that they had been exposed to contaminants for long durations in their environment. This study suggests that stress protein accumulation may provide a method for quantifying adverse biological impacts of exposure to chemicals in the environment when examined in wild populations from contaminated sites. This approach may also prove valuable in retrospective studies when used in banked specimens which have been collected as part of a large scale surveillance monitoring programs.