Electron Microscopic Visualization of Transcription
This extract was created in the absence of an abstract.
Excerpt
With the possible exception of DNA-containing cytoplasmic organelles, transcription and translation are compartmentalized in eucaryotic cells. That is, RNA polymerases transcribe nuclear DNA, and the various RNAs involved in translation migrate to the cytoplasm where protein synthesis occurs. On the other hand, in procaryotic cells, transcription and translation occur in the same region of the cell, at the same time, and in a coordinated manner. The transcription process has now been observed in both a eucaryotic cell, the amphibian oocyte (Miller and Beatty, 1969a, c), and in a procaryotic cell, the bacterium Escherichia coli (Miller et al., 1970).
METHODOLOGY
Amphibian oocytes in the lampbrush chromosome stage possess unique advantages for the study of structural aspects of transcription. First, there are thousands of chromosomal sites active in RNA synthesis. In addition, a large amplification of ribosomal RNA (rRNA) genes occurs during early oogenesis. During oocyte growth, these genes are present in...
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↵† Present address: Biology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
