A correlation between impaired editing of RNA and epilepsy is reported by scientists from the Max Planck Institute for Medical Research in Heidelberg/Germany. They succeeded in correcting the defect by genetic manipulation in the mouse.
The soon-to-be-completed human genome sequence will ring in a new era for biomedical research. For the first time the primary structure of all genes which determine human form and nature will be known. The sequences of the four nucleotides in all genes allow us to predict from the genetic code the exact amino acid sequence of all human proteins. That, however, there will be exceptions where an exact prediction will not be possible, is the message of a scientific study from the Max-Planck Institute for Medical Research in Heidelberg which appears in the latest issue of Nature (Nature, July 6, 2000). The reason for the uncertainty in predicting correctly all human proteins is that some gene sequences undergo in certain cells an editing process during their expression as RNA templates for protein synthesis (see figure).
Editing of RNA is a rare process that has been observed in mammals only in few cell types. Editing of RNA means that one or a few nucleotides in the RNA become altered. This alteration of nucleotides in RNA leads to proteins that contain in one or a few positions a different amino acid than the one predicted from the gene sequence. The substitution of single amino acids in certain positions of the protein changes the protein's function. It is thought that editing allows for tuning a given protein's function to different physiological requirements.
Interestingly, in mammals, all genes whose RNA transcripts undergo editing play a role in brain function. These include in particular receptors for the neurotransmitter glutamate which are intimately involved in learning and memory acquisition.
The scientists from the department of Molecular Neurobiology at the Max Planck
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Contact: Peter H. Seeburg
seeburg@mpimf-heidelberg.mpg.de
49-6221-486-495
Max-Planck-Gesellschaft
5-Jul-2000