FIG. 4.

Time course of heat shock induction of β-galactosidase (β-gal) synthesis in different groESL-lacZ transcription fusions. (A) C. crescentus NA1000 cells harboring transcription fusion pMA11, pRB19, or pRB22 were subjected to heat shock at 40°C, and aliquots of cells were pulse-labelled with [³⁵S]methionine for 2 min at the indicated times. Cells were then harvested by centrifugation, and protein extracts were immunoprecipitated with anti-β-galactosidase antibody to determine the rate of β-galactosidase synthesis before and during heat shock. (B) Relative rates of β-galactosidase synthesis determined by densitometry scanning of the autoradiograms.