MadSci Network: Neuroscience
Query:

Re: How does DNA control neurotransmitter receptors?

Date: Thu Aug 27 13:33:01 1998
Posted By: Alexander Craig, Grad student, Physiology/Neurobiology, University of Freiburg
Area of science: Neuroscience
ID: 903338896.Ns
Message:

I assume you are familiar with basic genetics, i.e. DNA is transcribed into  
RNA which is then translated into an amino acid chain (protein) on the 
ribosomes. 
The information on the strands of DNA is not in one piece though. It is 
usually fragmented into what are termed exons and introns where the exons 
code for the protein sequence and some other accessory information, e.g. 
information required for initiating translation. 
Exons can in some cases be arranged in different combinations when they are 
assembled into the messenger RNA, a process called (differential) splicing. 
And this is exactly the point where (structural as well as functional) 
variation among receptors of the same family can occur and/or is created 
(besides different DNA sequences due to mutation, duplication, or other 
genetic effects of course). Usually different splice variants can be shown 
to exist in different tissues or at different developmental stages in an 
organism. 
Which variant usually is expressed, i.e. which shows up on the cell's 
surface, is determined 
a) by all kinds of signals that impinge on the cell (at the surface or even 
from within) and which lead to activation and/or repression (through DNA 
binding proteins) of so called control elements in a gene's control region. 
b) how the splice apparatus works.
In this way DNA can affect the expression of neurotransmitter receptors. 
But note that DNA expression itself is regulated through various pathways 
that are turned on or off by external or internal stimuli. 
In many cases the exons are structured in such a way that one exon may code 
for what is known as a structural/functional domain, e.g. a substrate or 
ligand binding region in the protein. These may then be rearranged to yield 
different receptor variants (as described above)

I hope this answers your question.
Feel free to email me if 
you have further questions.


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