title: Requirement for Dicer in Maintenance of Monosynaptic Sensory-Motor Circuits in the Spinal Cord.
abstract: In contrast to our knowledge of mechanisms governing circuit formation, our understanding of how neural circuits are maintained is limited. Here, we show that Dicer, an RNaseIII protein required for processing microRNAs (miRNAs), is essential for maintenance of the spinal monosynaptic stretch reflex circuit in which group Ia proprioceptive sensory neurons form direct connections with motor neurons. In postnatal mice lacking Dicer in proprioceptor sensory neurons, there are no obvious defects in specificity or formation of monosynaptic sensory-motor connections. However, these circuits degrade through synapse loss and retraction of proprioceptive axonal projections from the ventral spinal cord. Peripheral terminals are also impaired without retracting from muscle targets. Interestingly, despite these central and peripheral axonal defects, proprioceptive neurons survive in the absence of Dicer-processed miRNAs. These findings reveal that Dicer, through its production of mature miRNAs, plays a key role in the maintenance of monosynaptic sensory-motor circuits.
authors.affiliation: Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
authors.forename: Fumiyasu
authors.initials: F
authors.lastname: Imai
authors.affiliation: Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Chen
authors.affiliation: Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA; Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA; Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Weirauch
authors.affiliation: Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA. Electronic address: yutaka.yoshida@cchmc.org.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D016923:Cell Death; D017353:Gene Deletion; D020869:Gene Expression Profiling; D008817:Mice, Mutant Strains; D009046:Motor Neurons / Q000166:cytology / Q000378:metabolism*; D011434:Proprioception; D012018:Reflex; D043244:Ribonuclease III / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000166:cytology / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology*; D013569:Synapses / Q000378:metabolism*
chemical_list: D043244:Ribonuclease III
keywords: motor neurons; proprioceptive sensory neurons; sensory-motor circuits; spinal cord