CLEM of TRIM37Δ cells expressing mNG-fused Lig^mut TRIM37. (A) Top left: Overlay of DIC and mNG fluorescence channels for three cells analyzed by serial section EM. Colored boxes in low-magnification (1,900×) views indicate the mNG-labeled condensate and the centrosome. Higher-magnification views (11,000×) of serial sections through the condensates reveal a highly ordered striated structure; a zoomed-in view shows regularly spaced stripes ∼90 nm apart; n, number of measurements. In cell 3, the condensate is associated with a centrosome. (B) Left: DIC-mNG overlay of a cell with a condensate close to a centrosome; this cell is in early mitosis. High-magnification view (11,000×) reveals a sheet-like object composed of hexagonally packed electron-dense puncta; the bottom part of the condensate appears to narrow and transition to the striated pattern seen in A. White scale bars in DIC-mNG overlay images, 20 µm. Black scale bars in EM images: low magnification, 2 µm; condensate and centrosome serial sections, 0.5 µm; zoomed-in view, 0.1 µm. S, section.