In vivo neuronal subtype-specific targets of Atoh1 (Math1) in dorsal spinal cord

J Neurosci. 2011 Jul 27;31(30):10859-71. doi: 10.1523/JNEUROSCI.0445-11.2011.

Abstract

Neural basic helix-loop-helix (bHLH) transcription factors are crucial in regulating the differentiation and neuronal subtype specification of neurons. Precisely how these transcription factors direct such processes is largely unknown due to the lack of bona fide targets in vivo. Genetic evidence suggests that bHLH factors have shared targets in their common differentiation role, but unique targets with respect to their distinct roles in neuronal subtype specification. However, whether neuronal subtype-specific targets exist remains an unsolved question. To address this question, we focused on Atoh1 (Math1), a bHLH transcription factor that specifies distinct neuronal subtypes of the proprioceptive pathway in mammals including the dI1 (dorsal interneuron 1) population of the developing spinal cord. We identified transcripts unique to the Atoh1-derived lineage using microarray analyses of specific bHLH-sorted populations from mouse. Chromatin immunoprecipitation-sequencing experiments followed by enhancer reporter analyses identified five direct neuronal subtype-specific targets of Atoh1 in vivo along with their Atoh1-responsive enhancers. These targets, Klf7, Rab15, Rassf4, Selm, and Smad7, have diverse functions that range from transcription factors to regulators of endocytosis and signaling pathways. Only Rab15 and Selm are expressed across several different Atoh1-specified neuronal subtypes including external granule cells (external granule cell layer) in the developing cerebellum, hair cells of the inner ear, and Merkel cells. Our work establishes on a molecular level that neuronal differentiation bHLH transcription factors have distinct lineage-specific targets.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Animals, Newborn
  • Basic Helix-Loop-Helix Transcription Factors / genetics*
  • Chick Embryo
  • Chromatin Immunoprecipitation / methods
  • Computational Biology
  • Electroporation / methods
  • Embryo, Mammalian
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Developmental / genetics*
  • Green Fluorescent Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Kinesins / genetics
  • LIM-Homeodomain Proteins
  • Male
  • Mice
  • Mice, Transgenic
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neurons / cytology*
  • Neurons / physiology*
  • Oligonucleotide Array Sequence Analysis
  • RNA, Messenger
  • Signal Transduction / genetics
  • Spinal Cord / cytology*
  • Transcription Factors / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Atoh1 protein, mouse
  • Basic Helix-Loop-Helix Transcription Factors
  • Homeodomain Proteins
  • LIM-Homeodomain Proteins
  • Lhx2 protein, mouse
  • Nerve Tissue Proteins
  • RNA, Messenger
  • Transcription Factors
  • Green Fluorescent Proteins
  • Neurog1 protein, mouse
  • Kif7 protein, mouse
  • Kinesins