Centromeric RNA transcripts in mitosis originate from local RNAPII transcription. (A) Schematic illustration of the different FISH protocols used to differentiate between DNA-FISH (including DNA denaturation at 80°C) and RNA-FISH. o/n, overnight. (B and C) Identical metaphase spread labeled with FISH probes for SAT III (B) or TTCTC (C) were imaged before and after RNase treatment. DNA-FISH signals (upper panel) and RNA-FISH signals (lower panel) are shown. White dotted lines indicate the acrocentric X-chromosomes. (D and E) Metaphase spreads labeled with FISH probes for SAT III (D) or TTCTC (E) after 2-h treatment with DRB (left) or tripto (right) are shown. White dotted lines indicate the acrocentric X-chromosomes. Bars, 3 µm.