Electron Microscopy: Active Genes

A. If the chromosomes are treated in a low salt solution and spread on a surface, the transcription loops expand and most proteins fall off. This does not give a view as close to nature as the previous figure, but the DNA axis and the growing RNA is more clearly visable.

B. One single transcription loop from fig A with the background removed. In this example it is very easy to follow the growing RNA along the DNA axis from the beginning of the gene(lower left) to the end of the gene(upper right).