Although electron microscopy has produced vast amounts of information on the workings of the cytoplasm, it has been relatively less successful for the nucleus. This is due to the intense packaging and fibrous nature of the nuclear contents, which makes it virtually impossible to follow a length of chromatin over any distance in the thin sections required for transmission electron microscopy. Add the sheer size of the nucleus (1000 times the volume of a mitochondrion) and it would require 200–300 serial sections to be cut, collected, and photographed at around 100 images per section before any three-dimensional reconstruction could be attempted, which is currently not a feasible task. Novel approaches such as the selective removal of components can simplify things. A fibrous structure can be seen by scanning EM after the biochemical removal of DNA and chromatin. This network of fibres running through the nucleus in thicker sections is called the nuclear matrix of scaffold ( Figure　7 c). Although this type of approach was initially controversial because the extensive biochemical protocols during preparation might create new structures (artefacts) rather than revealing the original organization, the idea of a fibrous supporting network running throughout the nuclear interior (the nucleoskeleton) is now generally accepted.