Exploring the Interaction Between TSC2, PTEN, and the NMDA Receptor in Animal Models of Tuberous Sclerosis

Abstract

Abstract : During the first year of this award, we completed much of the work proposed under Specific Aim 1: to examine the subunit composition of the NMDA receptor in Pten and Tsc2 knockout mice. First, we examined the subunit composition of the NMDA receptor in conditional NS-Pten knockout mice at postnatal day 21. The analysis revealed that NMDA receptor subunits are expressed at similar levels in NS-Pten mutant compared to wild type mice. However, the expected Pten loss and mTOR activation was partial. Second, we generated conditional NS-Tsc2 knockout mice and conducted an initial characterization of the phenotype. Heterozygous NS-Tsc2 mice appeared normal, but most homozygous mutant mice died prematurely. We thus analyzed NS-Tsc2 mutant mice at postnatal day 10, and found that the NMDA receptor appears normal. However, there was no Tsc2 loss or mTOR activation. Therefore, we further investigated the activity of the NS promoter used for both lines, and discovered that it does not induce significant gene deletion at developing ages. Together, the results indicate that the NS promoter is not suitable for our proposed studies. Therefore, we plan to switch to another Cre driver line, the NEX-Cre, which we previously shown to cause strong Pten gene deletion in conditional knock out mice.