HOUSTON (Oct. 6, 2005) -- Close your eyes and imagine you are in adarkened Carnegie Hall. Although it's pitch black, you know you aregetting closer to the stage as the music gets louder. If you have beenthere before, you have a sense of the location of the seats and aisles.You remain upright because you somehow know where your legs, arms andfeet are. Your head remains upright.
A variety of neurons or nerve cells makes it possible for you toapproach the stage and even find a seat without sight. Several of thoseneurons migrate from an embryonic structure called the rhombic lip, andmany of these in the auditory, vestibular and proprioreceptive (senseof position in space) systems come into being because of a single genecalled Math1, said researchers from Baylor College of Medicine in areport in the current issue of the journal Neuron.
"These three systems all seem to have a similarfunction. They all help us coordinate body perception and movement inspace. Now we know that one gene specifies the majority of theseneurons -- that this one gene has been conserved during evolution toexecute this task, said Dr. Huda Zoghbi, BCM professor of pediatricsand molecular and human genetics as well as a Howard Hughes MedicalInstitute investigator.
Zoghbi led the team that found the Math1 gene a few years agoand at that time, determined that it was important for the formation ofhair cells in the inner ear and some neurons in the cerebellum andintestine.
Now, mouse studies carried out by her and two graduatestudents, Matthew Rose and Vincent Y. Wang, demonstrate that Math1plays a pivotal role in the formation of many of the neurons importantin carrying hearing and vestibular and balance signals after they havebeen received and transmitted by the inner ear hair cells. The genealso specifies neurons that coordinate balance of body parts.
These nerve cells all arise in the rhombic lip,an embryonicstructure not known to produce some of these various neuronspreviously, said Rose.
"Here is a neuronal network that coordinates manydifferent types of sensations, and Math1 is required for manycomponents of it," said Zoghbi. "It is involved in the formation ofmany neurons that form key hubs for these senses. This is really veryinteresting. When one thinks of genes, one thinks of them specifyingcertain type of cells, but here is a gene that specifies many differenttypes of cells in a network designed to help us keep our balance findour position in space both by being aware of the position of our bodyparts and by hearing."
In a more prosaic sense, "this is the gene that makethe neurons you use when you get up in the night to get a drink ofwater and manage to do so in the dark" said Rose.
This research wassupported by the Howard Hughes Medical Institute, National ResearchService Award Kirschtein Predoctoral Fellowships, a Baylor ResearchAdvocates for Students Scientists (BRASS) Scholarship and a McNairScholarship.
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