Chromatin bridge is a mitotic occurrence that forms when telomeres of sister chromatids fuse together and fail to completely segregate into their respective daughter cells.

[1][2] The faithful inheritance of genetic information from one cellular generation to the next heavily relies on the duplication of deoxyribonucleic acid (DNA), as well as the formation of two identical daughter cells.

In particular, genetic studies have demonstrated that the loss of the enzymes BLM (Bloom's Syndrome Helicase) or FANCM each result in a dramatic increase in the number of chromatin bridges.

This occurs because loss of these genes causes an increase in chromosome fusions, either in an end-to-end manner or through topological entrapment (e.g., catenation or unresolved DNA cross-links), have also been associated with chromatin bridge formation.

When viewed under a fluorescence microscope and immunostained for cytological markers, these chromatin bridges appear to emanate from either centromeres, telomeres or DNA crosslinks (as marked by FANCD2).

In addition, immunofluorescence may be used as a laboratory technique to tag cells with specific fluorophores using antibodies, immune proteins created by B lymphocytes.

A chromatin bridge may also be observed using indirect immunofluorescence, in which anti-tubulin emits a green coloration when bound to microtubules in the presence of UV light.

Chromatin bridges can be difficult to locate utilizing fluorescence microscopy, as this phenomenon is not incredibly abundant and tend to appear faint against the dark background.