Nonexpression of a major heat shock gene in mouse plasmacytoma MPC-11.

The major heat shock gene coding for a 68,000-dalton protein was found to be silent in mouse plasmacytoma MPC-11 in both control and stressed cells. The block appears to be at the level of transcription, although RNA processing or instability has not been ruled out. It is not caused by a major deletion or rearrangement of the gene.