Cellular localization of high-molecular-mass heat shock proteins in murine cells.

We have previously prepared an antiserum raised against hsp105 of murine FM3A cells. The anti-hsp105 serum reacted to two isoforms of high-molecular-mass heat shock protein (HMM-HSP) having a molecular mass of 105,000 Da (hsp105A and hsp105B) in FM3A cells. While hsp105A and hsp105B were both synthesized and accumulated under non-stressed conditions, upon exposure to heat shock much more hsp105B was induced than hsp105A. When the cellular distribution of these hsp105s in murine 3T3 Swiss albino and C3H 10T1/2 cells was examined by immunofluorescence methods using the anti-hsp105 serum, the HMM-HSPs were localized in the cytoplasm and nuclei and were never found in the nucleoli of both 3T3 and C3H cells under non-stressed and stressed conditions.