See example dataset →

In 1998, Rogakou, Pilch, Orr, and Bonner discovered that every DNA double-strand break triggers phosphorylation of histone H2AX, creating a visible focus at the damage site. One focus equals one break. It remains the most sensitive DNA damage marker known, detecting damage down to the milliGray range, orders of magnitude more sensitive than the comet assay.

And yet foci counting is still largely manual. Papers routinely describe researchers visually counting dots in hundreds of nuclei. It is tedious, subjective, and rate-limiting.

Cytely detects foci per nucleus, measures their intensity and area, and links every data point back to the image. Gate on foci count, click on an outlier, see the actual nucleus.

How the assay runs

Segment nuclei from DAPI → detect foci in damage marker channel → count and measure per nucleus. For TAF/TIF: detect spots in both γH2AX and telomere channels independently, count per cell, compute colocalization ratio.

What you provide

  • Ch1: DAPI
  • Ch2: γH2AX or 53BP1 (IF)
  • Optional Ch3: telomere FISH probe (for TAF/TIF)
  • Optional Ch4: additional damage marker

What you get

  • Foci count per nucleus
  • Foci intensity
  • Foci area. For TAF: Dual-channel foci colocalization ratio per cell
  • Micronuclei (MNi) count per cell and % micronucleated cells (CBMN)

Ready to run

γH2AX foci, 53BP1 foci, RAD51 foci, TAF/TIF (telomere-associated foci via count-based colocalization), cytoplasmic chromatin fragments (CCF — see Senescence), micronucleus / micronuclei (MNi) counting and the cytokinesis-block micronucleus (CBMN) assay, nuclear buds and nucleoplasmic bridges.

Inquire for support

Comet assay (different imaging modality), live-cell DNA damage kinetics.

Explore the DNA Damage & Genotoxicity (Foci) assay →