Saturday, December 03, 2005

RNA splicing occurs in nerve-cell dendrites

A single gene is capable of directing the production of a number of different proteins. This is because each gene consists of regions ("exons") that code for amino acids that make up a protein, and other regions ("introns") that do not. Initially a gene is transcribed into RNA. But before this RNA is used to construct a protein, the introns are removed in a process called "splicing". Exons may be removed, as well, before the final messenger RNA is complete. Variant forms of the messenger RNA result depending on which exons are removed.

Normally this splicing process occurs in the nucleus of a cell. But new research shows that it can also occur in the parts of nerve cells known as "dendrites", which receive incoming signals from other nerve cells. It may be that the production of variant proteins from a single gene affects the strength of connections between nerve cells, and hence is involved in the processes of learning and memory.

RNA splicing occurs in nerve-cell dendrites

Protein diversity is a key aspect to the complexity of the central nervous system. Proteins are the workhorses of the cell and are generally responsible for insuring that cells function properly. When proteins interact with one another they can elicit specific physiological responses, including the generation and maintenance of memories. Changing protein identity, as can occur with splicing, can change the ability of the protein to interact with other proteins and therefore potentially change such physiological processes. With the dendrite being the initial site in the neuron where learning is thought to occur, the ability to create a diversity of mRNAs, through local splicing, and subsequent protein translation may permit exquisitely sensitive control of these cellular functions.


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