Breaking and Entering

Researchers capture live footage of a virus infecting a cell

half a dozen blurry magenta dots against a black background
Video: Kirchhausen lab

This article is part of Harvard Medical School’s continuing coverage of COVID-19.

In a first, scientists have captured on video all the steps a virus follows as it enters and infects a living cell in real time and in three dimensions.

They achieved the feat by using advanced imaging called lattice light sheet microscopy as well as chemical and genetic manipulation.

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The first part of the video shown here follows a virus engineered to sprout SARS-CoV-2 spike proteins (labeled pink) as it is captured at a cell surface and engulfed by a cellular compartment called an endosome. The virus then fuses with the endosome membrane and injects its genetic material (labeled blue) inside the cell — the steps necessary to kick off a cycle of viral infection and replication.

The second part of the video shows many such viruses inside the cell. The video spans about 4 minutes, with snapshots taken every 4 seconds.