63ª Reunião Anual da SBPC

C. Ciências Biológicas - 12. Neurociências e Comportamento - 1. Neurociências e Comportamento

POST-TRANSLATIONAL REGULATION OF PRONEURAL PROTEINS IN Xenopus laevis EMBRYOS

Andréia Pereira Turchetti 1 Renato de Lima Santos 2 Anna Philpott 3

1. Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, UFMG 2. PhD, Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, UFMG 3. PhD, Supervisor / Department of Oncology, Hutchison/MRC Research Centre, University of Cambridge

INTRODUÇÃO:

Neurogenin (Ngn) is a bHLH protein that when overexpressed regulates neurogenesis, in doing so, it upregulates both the Notch signalling pathway (responsible for the lateral inhibition process) and other transcription factors, such as MyT1, that leads to differentiation.

METODOLOGIA:

Two mutant forms of Ngn were produced to study the role of phosphorylation on Ngn’s activity: Ngn-SP (where serine-proline pairs were mutated to alanine-proline), that cannot undergo phosphorylation and Ngn-PM (where serine-proline were mutated to aspartic acid-proline), which mimics phosphorylation. To investigate the function and compare the relative neural-inducing activities of Ngn-WT, Ngn-SP and Ngn-PM in neural development and their interaction with Notch, Pax 6, Sox 2 and Geminin, which have been shown to regulate neurogenesis, different mRNA were injected into Xenopus laevis embryos and analysed neurogenesis through in situ hybridization.

RESULTADOS:

Ngn-SP is hyperactive in the promotion of ectopic neurogenesis in vivo, while Ngn-PM is less active when compared to the wild-type in a dose-dependent way, indicating that preventing phosphorylation promotes the ability of Ngn to drive ectopic neurogenesis. Ngn-WT, SP and PM proneural activities are downregulated via Notch signalling and by Pax 6, so phosphorylation appears not to play a role in their interactions. In related experiments, was discovered that xMyT1 can prevent Notch mediated upregulation of Hairy and that Sox 2 and Geminin cause developmental arrest and cell death, which increases the knowledge about the regulation of neurogenesis.

CONCLUSÃO:

Ngn-SP is a hyperactive form of Ngn, which is downregulated via Notch signalling and by Pax 6. Interesting, phosphorylation is not significant in their interactions to enhance neurogenesis.

Palavras-chave: Neurogenin, Post-translational regulation, Xenopus laevis.