Fig. 7. Colocalization of bright psoralen and nascent RNA signals on heat-shock puffs. (A) Comparison of psoralen and nascent RNA signals on polytene chromosomes dissected from heat-shocked larvae. (B,C) Detailed inspection on the heat-shock puffs at 87A and 87B. (C) Signal intensities of biotinylated psoralen (green), nascent RNA (pink) and DAPI (blue), and ratio of signal intensity of biotinylated psoralen to DNA (yellow) quantified along the region indicated in (B). Bar, 10 µm.