X-linked Intellectual Disability Gene CUL4B Inhibits The Self-renewal Of Neural Stem Cells Via Regulating Substrate Protein Prdx3

BackgroundMutations in human CUL4B gene led to syndromic X-linked intellectual disability (XLID). The N-terminal of CUL4B binds with DDB1 (DNA damage binding 1), and the C-terminal of CUL4B binds with ROC1 (RING-box protein 1);. CUL4B E3 ubiquitin ligase complex and its specific substrates may play an important role in nervous system development.With two-dimensional gel electrophoresis and mass spectrometry technology, we have identified peroxiredoxin Ⅲ (Prdx3) as a novel specific substrate of the CUL4B E3 ubiquitin ligase complex in HEK293 cell line. Further studies of CUL4B/Prdx3 in the Cul4bNestin-Cre mice model might contribute to reveal the pathogenic mechanism of CUL4B mutation in XLID disease.ObjectiveThe thesis focused on the molecular mechanism of CUL4B and its specific substrate protein Prdx3 in the self-renewal process of neural stem cells.Methods1、Utilize the nervous system specific Cul4b knock-out mice (Cul4bNestin-Cre) and littermate control mice, respectively extract forebrain tissue then detect the expression of CUL4B and Prdx3 using Western Blot and immunohistochemistry technology.2、Separate and culture the neural stem cells of the nervous system specific Cul4b knock-out mice (Cul4bNestin-Cre) and littermate control mice, extract total cellular protein then detect the expression of CUL4B and Prdx3 using Western Blot and immunofluorescence technology.3、Study the influence of Cul4b on the self-renewal of neural stem cells. Detect the self-renewal ability and the differentiation ability.4、Detect the influence of CUL4B/Prdx3 on related PTEN/AKT signal pathway.Results1、Prdx3 were accumulated in the forebrain tissue as well as neural stem cells of Cul4bNestin-Cre mice model.2、The self-renewal ability of Cul4bNestin-Cre NSCs decreased.3、Prdx3 binded with PTEN and influenced AKT signal pathway.ConclusionsThe theis focused on the X-linked intellectual disability gene CUL4B functions on self-renewal of neural stem cells via its substrate protein Prdx3. This research might provid some scientific clues for revealing the molecular mechanism of XLID disease caused by CUL4B mutations.