Polysome

[4] Electron microscopy technologies such as staining,[5] metal shadowing,[6] and ultra-thin cell sections were the original methods to determine polysome structure.

The development of cryo-electron microscopy techniques has allowed for increased resolution of the image, leading to a more precise method to determine structure.

An investigation of the ratio of polyribosomal shape elucidated that a high number of circular and zigzag polysomes were found after several rounds of translation.

This dense packing can determine their function as regulators of translation, with 3-D polyribosomes being found in sarcoma cells using fluorescence microscopy.

The restriction of inter-ribosomal contacts causes a round-shape configuration that arranges ribosomes along the mRNA so that the entry and exit sites form a smooth pathway.

[1] Polysomal profiling is a technique that uses cycloheximide to arrest translation and a sucrose gradient to separate the resulting cell extract by centrifugation.

Polysomal profiling is optimally applied to cultured cells and tissues to track the translational status of an identified mRNA as well as measure ribosome density.

For example, polysomal profiling was used in a study to investigate the effect of vesicular stomatitis virus (VSV) in mammalian cells.