Er81 is expressed in a subpopulation of layer 5 neurons in rodent and primate neocortices

Neuroscience. 2006;137(2):401-12. doi: 10.1016/j.neuroscience.2005.08.075. Epub 2005 Nov 14.

Abstract

Laminar organization is a fundamental cytoarchitecture in mammalian CNS and a striking feature of the neocortex. ER81, a transcription factor, has recently been utilized as a marker of cells in the layer 5 of the neocortex. We further pursued the distribution of ER81 to investigate the identity of the ER81-expressing cells in the brain. Er81 transcript was expressed in a subset of pyramidal cells that were scattered throughout the entire width of layer 5. In the rat cortex, Er81 transcripts were first detected in the ventricular zone at E15, remained expressed in putative prospective layer 5 neurons during infant and juvenile stages. The ER81-expressing subpopulation in adult layer 5 neurons did not segregate with the phenotypes of the projection targets. By retrograde labeling combined with immunohistochemistry or reverse transcription-polymerase chain reaction analysis, we found ER81 expression in nearly all of the layer 5 neurons projecting to the spinal cord or to the superior colliculus, while in only one-third of the layer 5 neurons projecting to the contralateral cortex. Er81 was also detected in layer 5 neurons in a P2 Japanese macaque monkey but not in adult monkey cortices. These findings suggest that a neuron class defined by a molecular criterion does not necessarily segregate with that defined by an anatomical criterion, that ER81 is involved in cell differentiation of a subset of layer 5 projection neurons and that this mechanism is conserved among rodents and primates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / physiology
  • Animals
  • Animals, Newborn
  • Base Sequence
  • Cell Differentiation / physiology
  • Conserved Sequence / genetics
  • Corpus Callosum / cytology
  • Corpus Callosum / embryology
  • Corpus Callosum / growth & development
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Efferent Pathways / cytology
  • Efferent Pathways / embryology*
  • Efferent Pathways / growth & development*
  • Functional Laterality / physiology
  • Macaca fascicularis
  • Mice
  • Mice, Inbred C3H
  • Mice, Inbred C57BL
  • Mice, Inbred ICR
  • Molecular Sequence Data
  • Neocortex / cytology
  • Neocortex / embryology*
  • Neocortex / growth & development*
  • Neurons / classification
  • Neurons / cytology
  • Neurons / metabolism*
  • Pyramidal Cells / cytology
  • Pyramidal Cells / metabolism
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Rats, Wistar
  • Species Specificity
  • Spinal Cord / cytology
  • Spinal Cord / embryology
  • Spinal Cord / growth & development
  • Superior Colliculi / cytology
  • Superior Colliculi / embryology
  • Superior Colliculi / growth & development
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • DNA-Binding Proteins
  • Etv1 protein, mouse
  • RNA, Messenger
  • Transcription Factors