Participants involved: Paris (responsible).
Collaborating institutes: Créteil.

Objectives

1. constuction of knockout and transgenic mouse models for MRX
2. behavioral profiles of the MRX mouse models
3. histological and physiological characteristics of MRX mouse models

Methodology and study materials

Constructs for homologous recombination in mouse embryonic stem cells will consist of oligophrenin 1 gene sequences, which are disrupted by neomycin and thymidine kinase selection markers. The lacZ gene will be fused in frame with the N-terminal part of the targeted proteins, with the aim of placing their expression under control of endogenous promoters (participant Paris).

For oligophrenin-1 and PAK3 transgenic mice, promoters such as a-enolase (a neuronal specific promoter) or nestin (widely active in the developing nervous system) will be used to overexpress these MRX genes in the mouse brain (participant Paris).

Antibodies specific to the various MRX proteins (oligophrenin 1, PAK3, TM4SF2 and αPIX) will be raised in rabbits by using bacterially expressed fusion proteins. Hippocampal brain sections of the MRX mouse models and control animals will be used to establish cell lines (work package 7) and to determine gene expression profiles (work package 8). These animals will also be used for behavioural studies and immunohistological analyses (participant Paris).

The resulting transgenic and knockout mice will be analysed using histopathological and electrophysiological techniques as well as behavioural tests. The behavioural studies require that the mutant animals, that are deficient for or are over-expressing MRX genes, are genetically nearly identical besides the introduced MRX mutation (participant Creteil).