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Identification of OTX1 and OTX2 As Two Possible Molecular Markers for Sinonasal Carcinomas and Olfactory Neuroblastomas
07:00

Identification of OTX1 and OTX2 As Two Possible Molecular Markers for Sinonasal Carcinomas and Olfactory Neuroblastomas

Published on: February 28, 2019

Molecular links among the causative genes for ocular malformation: Otx2 and Sox2 coregulate Rax expression

Hiroki Danno1, Tatsuo Michiue, Keisuke Hitachi

  • 1Department of Life Sciences (Biology), Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.

Proceedings of the National Academy of Sciences of the United States of America
|April 4, 2008
PubMed

Insights

Ocular malformation genes Otx2 and Sox2 directly regulate Rax expression. Their interaction coordinates eye development, linking genes responsible for anophthalmia and microphthalmia.

Area of Science:

  • Developmental Biology
  • Genetics
  • Ophthalmology

Background:

  • Neural-related genes like Sox2, Pax6, Otx2, and Rax are linked to severe ocular malformations (anophthalmia, microphthalmia).
  • The functional relationship and upstream signaling pathways connecting these genes remain incompletely understood.

Purpose of the Study:

  • To investigate the upstream signaling controlling Xenopus Rax (Rx1) expression.
  • To identify direct upstream regulators of Rax and elucidate their functional interactions in eye development.

Main Methods:

  • Analysis of upstream signaling pathways for Xenopus Rax.
  • Identification of Otx2 and Sox2 as direct upstream regulators.
  • Chromatin immunoprecipitation (ChIP) assays to confirm protein binding to conserved noncoding sequence 1 (CNS1).
  • Reporter assays to assess transcriptional activation via CNS1.
  • Co-immunoprecipitation assays to study protein-protein interactions.

Main Results:

  • Otx2 and Sox2 proteins were identified as direct upstream regulators of Rax.
  • Endogenous Otx2 and Sox2 bind to CNS1, a conserved noncoding element upstream of the Rax promoter, which is crucial for transcriptional activity.
  • Otx2 and Sox2 synergistically activate transcription via CNS1 and physically interact, with this interaction being sensitive to disease-associated Sox2 mutations.

Conclusions:

  • The direct interaction and interdependence between Otx2 and Sox2 proteins are critical for coordinating Rax expression during eye development.
  • These findings establish molecular linkages between Otx2, Sox2, and Rax, explaining their collective role in causing ocular malformations.

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