A new GFP-tagged line reveals unexpected Otx2 protein localization in retinal photoreceptors
1 IGFL, UMR CNRS 5242-INRA 1237-ENS, IFR128 Lyon-Gerland, 46 allée d'Italie, 69364 Lyon Cedex 07, France
2 LBMC, UMR CNRS 5239 -ENS, IFR128 Lyon-Gerland, 46 allée d'Italie, 69364 Lyon Cedex 07, France
3 Institut Pasteur, CNRS URA 2578, 28 rue du Docteur Roux, 75724 Paris cedex 15, France
4 Embryology Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
BMC Developmental Biology 2007, 7:122 doi:10.1186/1471-213X-7-122Published: 2 November 2007
Dynamic monitoring of protein expression and localization is fundamental to the understanding of biological processes. The paired-class homeodomain-containing transcription factor Otx2 is essential for normal head and brain development in vertebrates. Recent conditional knockout studies have pointed to multiple roles of this protein during late development and post-natal life. Yet, later expression and functions remain poorly characterized as specific reagents to detect the protein at any stage of development are still missing.
We generated a new mouse line harbouring an insertion of the GFP gene within the Otx2 coding sequence to monitor the gene activity while preserving most of its functions. Our results demonstrate that this line represents a convenient tool to capture the dynamics of Otx2 gene expression from early embryonic stages to adulthood. In addition, we could visualize the intracellular location of Otx2 protein. In the retina, we reinterpret the former view of protein distribution and show a further level of regulation of intranuclear protein localization, which depends on the cell type.
The GFP-tagged Otx2 mouse line fully recapitulates previously known expression patterns and brings additional accuracy and easiness of detection of Otx2 gene activity. This opens up the way to live imaging of a highly dynamic actor of brain development and can be adapted to any mutant background to probe for genetic interaction between Otx2 and the mutated gene.