Resinless section electron microscopy of HeLa cell mitotic architecture.

The use of resinless sections extends embedment-free electron microscopy to the cytoskeleton of thick specimens. Here we examine HeLa cells rounded at mitosis. Extraction of mitotic HeLa cells with Triton X-100 removes lipids and soluble proteins, leaving the cytoskeletal framework and spindle apparatus. After fixation, the samples are embedded and sectioned, and the temporary embedding resin is removed for direct visualization in the electron microscope. The micrographs show that the cytoskeletal framework, chromosomes, spindle, and centrioles form an interconnected entity. The pericentriolar region, indistinct in conventional micrographs, appears composed of distinct fibers interconnecting the spindle microtubules and centriole. The resinless sections also reveal characteristic lacunae at late anaphase/early telophase. These probably result from reformation of the interphase cytoskeleton lagging reassembly of the nucleus.