FIG. 3.

The htr1 mutation depressed transcription of HTA1-HTB1 and failed to complement hir3. RNA blot analysis was performed after 30 min of growth in the absence (−) or presence (+) of HU. The diploids were formed by crossing SL1006-1B (htr1) and SL1006-1D (HTR1) with W303 (HIR3) and W303Δ3 (hir3). The constitutively transcribed gene PRT1 was used as an internal loading control since its abundance is not affected by HU.