Proteomics analysis of an UBE3A knockout mouse modelling Angelman syndrome

Abstract

Angelman syndrome is a neurobehavioral disease associated with the loss of maternally expressed E3 ubiquitin protein ligase, Ube3a. Ube3a gene is biallelically expressed in all tissue except cerebellum, Purkinje cells and hippocampus, in which Ube3a is expressed exclusively from maternally inherited chromosome. By using an Ube3a knockout mouse model, the effect of loss of Ube3a in brain has been studied using 2-D DIGE method. Due to the fact that Ube3a is involved in ubiquitin-related proteasomal degradation, its substrates and downstream targets are expected to be differentially expressed in knockout and wild-type models. A total of 94 proteins from cerebellum and 74 proteins from hippocampus were found differentially expressed in the Ube3a knockout mice using 2-D DIGE, 14 of them were statistically significant. Western blot and Real Time RT PCR were then employed to examine the protein level and mRNA level of those proteins, respectively. CaBP was found downregulated at mRNA as well as protein level; its function as calcium ion buffer may play an inductive role in the seizure observed in AS mouse model and patients.