Scientific Publications by FDA Staff

Science 2014 Mar 14;343(6176):1264-6

Dlk1 promotes a fast motor neuron biophysical signature required for peak force execution.

Muller D1, Cherukuri P, Henningfeld K, Poh CH, Wittler L, Grote P, Schlüter O, Schmidt J, Laborda J, Bauer SR, Brownstone RM, Marquardt T

Motor neurons, which relay neural commands to drive skeletal muscle movements, encompass types ranging from "slow" to "fast," whose biophysical properties govern the timing, gradation, and amplitude of muscle force. Here we identify the noncanonical Notch ligand Delta-like homolog 1 (Dlk1) as a determinant of motor neuron functional diversification. Dlk1, expressed by ~30% of motor neurons, is necessary and sufficient to promote a fast biophysical signature in the mouse and chick. Dlk1 suppresses Notch signaling and activates expression of the K(+) channel subunit Kcng4 to modulate delayed-rectifier currents. Dlk1 inactivation comprehensively shifts motor neurons toward slow biophysical and transcriptome signatures, while abolishing peak force outputs. Our findings provide insights into the development of motor neuron functional diversity and its contribution to the execution of movements.