Figure 1.—

Temporal control of cell-specific transgene expression. In an animal lacking the normal heat-shock response due to loss of HSF-1 activity, hsf-1 is introduced in a desired subset of cells using a cell-specific promoter (pro). Since HSF-1 is present only in targeted cells, heat shock results in cell-specific transcription from heat-shock-responsive promoters (hsp). Therefore, any transgene under the control of a heat-shock promoter will be selectively expressed in the desired cells following a heat shock. Blue circles, HSF-1 protein. Green hexagons, protein of interest.