Noonan syndrome gain-of-function mutations in NRAS cause zebrafish gastrulation defects

Autor: Vincent Runtuwene, Mark van Eekelen, John Overvoorde, Holger Rehmann, Helger G. Yntema, Willy M. Nillesen, Arie van Haeringen, Ineke van der Burgt, Boudewijn Burgering, Jeroen den Hertog
Jazyk: angličtina
Rok vydání: 2011
Předmět:
Zdroj: Disease Models & Mechanisms, Vol 4, Iss 3, Pp 393-399 (2011)
Druh dokumentu: article
ISSN: 1754-8403
1754-8411
DOI: 10.1242/dmm.007112
Popis: SUMMARY Noonan syndrome is a relatively common developmental disorder that is characterized by reduced growth, wide-set eyes and congenital heart defects. Noonan syndrome is associated with dysregulation of the Ras–mitogen-activated-protein-kinase (MAPK) signaling pathway. Recently, two mutations in NRAS were reported to be associated with Noonan syndrome, T50I and G60E. Here, we report a mutation in NRAS, resulting in an I24N amino acid substitution, that we identified in an individual bearing typical Noonan syndrome features. The I24N mutation activates N-Ras, resulting in enhanced downstream signaling. Expression of N-Ras-I24N, N-Ras-G60E or the strongly activating mutant N-Ras-G12V, which we included as a positive control, results in developmental defects in zebrafish embryos, demonstrating that these activating N-Ras mutants are sufficient to induce developmental disorders. The defects in zebrafish embryos are reminiscent of symptoms in individuals with Noonan syndrome and phenocopy the defects that other Noonan-syndrome-associated genes induce in zebrafish embryos. MEK inhibition completely rescued the activated N-Ras-induced phenotypes, demonstrating that these defects are mediated exclusively by Ras-MAPK signaling. In conclusion, mutations in NRAS from individuals with Noonan syndrome activated N-Ras signaling and induced developmental defects in zebrafish embryos, indicating that activating mutations in NRAS cause Noonan syndrome.
Databáze: Directory of Open Access Journals
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