Compensatory Actions of Ldb Adaptor Proteins During Corticospinal Motor Neuron Differentiation

Cereb Cortex. 2017 Feb 1;27(2):1686-1699. doi: 10.1093/cercor/bhw003.

Abstract

Although many genes that specify neocortical projection neuron subtypes have been identified, the downstream effectors that control differentiation of those subtypes remain largely unknown. Here, we demonstrate that the LIM domain-binding proteins Ldb1 and Ldb2 exhibit dynamic and inversely correlated expression patterns during cerebral cortical development. Ldb1-deficient brains display severe defects in proliferation and changes in regionalization, phenotypes resembling those of Lhx mutants. Ldb2-deficient brains, on the other hand, exhibit striking phenotypes affecting layer 5 pyramidal neurons: Immature neurons have an impaired capacity to segregate into mature callosal and subcerebral projection neurons. The analysis of Ldb2 single-mutant mice reveals a compensatory role of Ldb1 for Ldb2 during corticospinal motor neuron (CSMN) differentiation. Animals lacking both Ldb1 and Ldb2 uncover the requirement for Ldb2 during CSMN differentiation, manifested as incomplete CSMN differentiation, and ultimately leading to a failure of the corticospinal tract.

Keywords: Ldb; brain development; corticospinal motor neurons; differentiation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Cell Differentiation* / physiology
  • DNA-Binding Proteins / deficiency*
  • Gene Expression Regulation, Developmental / physiology*
  • LIM Domain Proteins / deficiency*
  • Mice, Transgenic
  • Motor Neurons / metabolism*
  • Neurogenesis / physiology
  • Pyramidal Tracts / metabolism*
  • Transcription Factors / deficiency*
  • Transcription Factors / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • DNA-Binding Proteins
  • LIM Domain Proteins
  • Ldb1 protein, mouse
  • Ldb2 protein, mouse
  • Transcription Factors