Thursday, 29 March 2012

c-MAF transcription factor and touch

Level: 3+

Wende et al. The transcription factor c-Maf controls touch receptor development and function. Science. 2012 Mar 16;335(6074):1373-6.

The sense of touch relies on detection of mechanical stimuli by specialized mechanosensory neurons.  This study shows that the transcription factor c-Maf/c-MAF is crucial for mechanosensory function in mice and humans. The development and function of several rapidly adapting mechanoreceptor types are disrupted in c-Maf mutant mice. In particular, Pacinian corpuscles, a type of mechanoreceptor specialized to detect high-frequency vibrations, are severely atrophied. In line with this, sensitivity to high-frequency vibration is reduced in humans carrying a dominant mutation in the c-MAF gene. This work identifies a key transcription factor specifying development and function of mechanoreceptors and their end organs.

"In humans, dominant c-MAF mutations are associated with ocular developmental abnormalities and cataracts, but their effects on mechanosensation have not been examined. Encouraged by our results in mice, we tested touch sensitivity in a family comprising four carriers of the dominant Arg288→Pro288 (R288P) c-MAF mutation. This mutation in the auxiliary DNA binding domain interferes with c-MAF–dependent transcriptional activation but does not eliminate c-MAF function and represents one of three known cataract-causing point mutations in c-MAF. To assess the function of Meissner and Pacinian corpuscles, we tested vibrotactile acuity over a wide range of frequencies (5 to 240 Hz). Pacinian corpuscles are essential for the detection of small-amplitude high-frequency vibrations. We observed a large increase in the vibration amplitude required to elicit responses in c-MAF mutant carriers at high but not low frequencies. Tactile spatial acuity, that is, the ability to distinguish grids of different spacing, is thought to depend on hair follicle afferents/Meissner corpuscles/Merkel cell-neurite complexes and was not significantly changed. Thus, the R288P c-MAF mutation interferes with normal vibration detection in humans."

Additional reading:  Pacinian corpuscles

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