Positional differences of axon growth rates between sensory neurons encoded by runx3

LALLEMEND F; STERZENBACH U*; HADJAB-LALLEMEND S*; AQUINO JB; CASTELO BRANCO G; VILLAESCUSA JC; SINHA I; LEVANON D; WANG Y; FRANCK MCM; KHARCHENKO O; ADAMEYKO I; LINNARSSON S; GRONER Y; TURNER E; ERNFORS P

EMBO JOURNAL

NATURE PUBLISHING GROUP

Lugar: Londres; Año: 2012 vol. 31 p. 3718 - 3729

0261-4189

* These authors have equally contributed to this work The formation of functional connectivity in the nervous system is governed by axon guidance that instructs nerve growth and branching during development, implying asimilarity between neuronal subtypes in terms of nerveextension. We demonstrate the molecular mechanism of another layer of complexity in vertebrates by defining atranscriptional program underlying growth differences between positionally different neurons. The rate of axon extension of the early subset of embryonic dorsal rootganglion sensory neurons is encoded in neurons at different axial levels. This code is determined by a segmental pattern of axial levels of Runx family transcription factorRunx3. Runx3 in turn determines transcription levels of genes encoding cytoskeletal proteins involved in axon extension, including Rock1 and Rock2 which have ongoingactivities determining axon growth in early sensory neurons and blocking Rock activity reverses axon extension deficits of Runx3/ neurons. Thus, Runx3 acts to regulate positional differences in axon extension properties apparently without affecting nerve guidance andbranching, a principle that could be relevant to other parts of the nervous system.