Howard Hughes Medical Institute (HHMI) researchers have deciphered a key part of the regulatory code that governs how motor neurons in the spinal cord connect to specific target muscles in the limbs.

The researchers said that understanding this code may help guide progress in restoring motor neuron function in people whose spinal cords have been damaged by trauma or disease. The studies suggest that the code — which involves members of the family of transcription factors encoded by the Hox genes — could also govern the establishment of other spinal cord circuits. This circuitry includes interneurons that control motor neuron firing patterns and sensory neurons that transmit feedback information on muscle action.

Creation of antibodies that react with each of the 21 Hox proteins expressed by spinal cord motor neurons was an important technical advance that enabled the researchers to crack this code. Using these antibodies, Dasen and colleagues pinpointed the pattern of expression of each protein within the set of motor neurons that project to limb muscles.

Source: Howard Hughes Medical Institute news release