T-box transcription regulator Tbr2 is essential for the formation and maintenance of Opn4/melanopsin-expressing intrinsically photosensitive retinal ganglion cells

Chai An Mao, Hongyan Li, Zhijing Zhang, Takae Kiyama, Satchidananda Panda, Samer Hattar, Christophe P. Ribelayga, Stephen L. Mills, Steven W. Wang

Research output: Contribution to journalArticle

Abstract

Opsin 4 (Opn4)/melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) play a major role in non-image-forming visual system. Although advances have been made in understanding their morphological features and functions, the molecular mechanisms that regulate their formation and survival remain unknown. Previously, we found that mouse T-box brain 2 (Tbr2) (also known as Eomes), a T-box-containing transcription factor, was expressed in a subset of newborn RGCs, suggesting that it is involved in the formation of specific RGC subtypes. In this in vivo study, we used complex mouse genetics, single-cell dye tracing, and behavioral analyses to determine whether Tbr2 regulates ipRGC formation and survival. Our results show the following: (1) Opn4 is expressed exclusively in Tbr2-positive RGCs; (2) no ipRGCs are detected when Tbr2 is genetically ablated before RGC specification; and (3) most ipRGCs are eliminated when Tbr2 is deleted in established ipRGCs. The few remaining ipRGCs display abnormal dendritic morphological features and functions. In addition, some Tbr2-expressing RGCs can activate Opn4 expression on the loss of native ipRGCs, suggesting that Tbr2-expressing RGCs may serve as a reservoir of ipRGCs to regulate the number of ipRGCs and the expression levels of Opn4.

Original languageEnglish (US)
Pages (from-to)13083-13095
Number of pages13
JournalJournal of Neuroscience
Volume34
Issue number39
DOIs
Publication statusPublished - Sep 24 2014

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Keywords

  • Circadian
  • Eomes
  • ipRGC
  • Retina development
  • RGC subtypes
  • Tbr2

ASJC Scopus subject areas

  • Neuroscience(all)
  • Medicine(all)

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