Until this discovery, researchers did not fully understand the complex genetic process that enables Schwann cells, found in the peripheral nervous system, to coat nerves with myelin.
The Newly Discovered Role of EGR2
During this study, the scientists found that EGR2 produces a protein that activates several other genes necessary for myelin production. Some of these genes contain the information needed to make peripheral myelin protein 22 (PMP-22) and myelin protein zero (MPZ). MPZ is the most abundant protein in myelin in the peripheral nervous system.
The overproduction or underproduction of the proteins PMP22 and MPZ account for the majority of inherited peripheral neuropathies, Dr. Svaren said.
Ultimately, the sequence of activating genes "switches on" the Schwann cell, which wraps the nerve axon, the arm-like projection that conveys nerve impulses, in a myelin sheath.
The scientists' research also resolved a long-standing mystery surrounding why a single mutant copy of the EGR2 gene disrupts the functioning of the normal EGR2 gene, leading to a disorder of the nervous system.
In many genetic conditions, the unaffected copy of an affected gene continues to produce its protein. However, the researchers found that the mutant EGR2 copy interferes with the interaction between the normal EGR2 gene and another myelin gene, SOX10, as the two try to work together to produce the myelin protein MPZ.
By understanding the process which creates myelin, researchers may now be able to investigate new therapies for disorders affecting myelin.
"Our research has uncovered a whole new mechanism for regulating myelin genes," said Dr. Svaren. "Our hope is to exploit this knowledge so that we can adjust the levels of myelin genes such as PMP22 and MPZ, and thereby create an effec
Source:NIH/National Institute of Child Health and Human Development