Investigation of the molecular mechanisms of the human DDX3X R534C mutant associated with neurodevelopment disorders

• Grant number: 23/13800-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2024
• End date: February 29, 2024
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Principal Investigator: Ivan Rosa e Silva
• Grantee: Raul Fonseca dos Reis Motta
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil

Abstract

DDX3X is an ATP-dependent RNA helicase from the DEAD-box family with an important role in RNA metabolism, being involved in the liquid-liquid phase separation (LLPS) process in the cell. Biomolecular condensation is a new field in Biology involved in membraneless organelles formation such as stress granules, for which DDX3X is essential. DDX3X R534C mutation, located to the ATP binding region, was identified in patients with neurodevelopment disorders, showing the relevance of the region for DDX3X function. This project aims to investigate the effects of the R534C mutation on the molecular mechanisms of DDX3X, including its LLPS process. We will express and purify the recombinant wild-type and R534C proteins. For the LLPS experiment, physical-chemical conditions will be explored to investigate protein solubility and the biomolecular condensates will be observed by light microscopy. DDX3X ATPase activity will be studied using UV absorption spectroscopy of the product in a coupled reaction to understand how the mutation influences ATP binding and hydrolysis. Our results will enable us to characterize the molecular mechanisms of a less studied mutation in DDX3X, contributing to the expansion of the knowledge on neurodevelopment disorders.