These authors contributed equally to this work.
Expanding the phenotype associated with FOXG1 mutations and in vivo FoxG1 chromatin-binding dynamics
Article first published online: 13 DEC 2011
© 2011 John Wiley & Sons A/S
Volume 82, Issue 4, pages 395–403, October 2012
How to Cite
De Filippis, R., Pancrazi, L., Bjørgo, K., Rosseto, A., Kleefstra, T., Grillo, E., Panighini, A., Cardarelli, F., Meloni, I., Ariani, F., Mencarelli, M., Hayek, J., Renieri, A., Costa, M. and Mari, F. (2012), Expanding the phenotype associated with FOXG1 mutations and in vivo FoxG1 chromatin-binding dynamics. Clinical Genetics, 82: 395–403. doi: 10.1111/j.1399-0004.2011.01810.x
- Issue published online: 11 SEP 2012
- Article first published online: 13 DEC 2011
- Accepted manuscript online: 17 NOV 2011 12:56PM EST
- Received 14 June 2011, revised and accepted for publication 14 November 2011
- chromatin affinity;
- FOXG1 gene;
- FRAP assay;
- Rett syndrome
Mutations in the Forkhead box G1 (FOXG1) gene, a brain specific transcriptional factor, are responsible for the congenital variant of Rett syndrome. Until now FOXG1 point mutations have been reported in 12 Rett patients. Recently seven additional patients have been reported with a quite homogeneous severe phenotype designated as the FOXG1 syndrome. Here we describe two unrelated patients with a de novo FOXG1 point mutation, p.Gln46X and p.Tyr400X, respectively, having a milder phenotype and sharing a distinctive facial appearance. Although FoxG1 action depends critically on its binding to chromatin, very little is known about the dynamics of this process. Using fluorescence recovery after photobleaching, we showed that most of the GFP-FoxG1 fusion protein associates reversibly to chromatin whereas the remaining fraction is bound irreversibly. Furthermore, we showed that the two pathologic derivatives of FoxG1 described in this paper present a dramatic alteration in chromatin affinity and irreversibly bound fraction in comparison with Ser323fsX325 mutant (associated with a severe phenotype) and wild type Foxg1 protein. Our observations suggest that alterations in the kinetics of FoxG1 binding to chromatin might contribute to the pathological effects of FOXG1 mutations.