Research highlight: Divergent evolution shapes brain connectivity in mammals

ENP researcher Alain Chédotal (Institut de la Vision) studies axon guidance mechanisms at the midline of the developing nervous system. The team including ENP student and co-first author Heike Blockus provides evidence for an evolutionary signaling switch of the axon guidance receptor Robo3 in mammals. Unlike other Robo receptors, mammalian Robo3 do not bind Slit ligands. Against the dogmatic view that Slit-Robo solely mediate chemorepulsion, they show that adaptive evolution conferred chemoattractive signaling properties to Robo3. The authors propose that subtle adaptive mutations of Robo3 in mammals helped connecting the cortical motor system to the cerebellar system thereby improving the planning and learning of motor tasks in mammals.

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Zelina P, Blockus H, Zagar Y, Péres A, Friocourt F, Wu Z, Rama N, Fouquet C, Hohenester E, Tessier-Lavigne M, Schweitzer J, Roest Crollius H and Chédotal A. Signaling Switch of the Axon Guidance Receptor Robo3 during Vertebrate Evolution


Figure: Contrarily to their wildtype counterpart (green) pontine neurons lacking the axon guidance receptor Robo3 (red) fail to reach the midline and project to the ipsilateral cerebellum.