The Study Of Schizophrenia-like Phenotype And Primary Molecular Mechanism In REGγ Knockout Mice

REGy, also known as PA28y, Psme3, or Ki antigen, is an important component in unbiquitin-independent proteasome degradation. It has been proved to selectively degrade intact proteins such as SRC-3 or p21, and regulate related biological and pathological process. There are more targets to be identified. REGy knockout mice were found to be growth retardation and slight immune defects. The phenotype of the REGy knockout mice in the nervous system has not been reported. In this dissertation, the phenotypes of REGy knockout mice were analyzed in a number of behavioral experiments, such as the spontaneous activity, motor coordination, spatial memory, anxiety and schizophrenia. The results showed that the REGy knockout mice exhibited the increased spontaneous activity and the stereotypies, decreased prepulse inhibition and deficiency in nest-building capability. There was no obvious difference in the motor coordination, spatial memory and anxiety. The behavioral experiments demonstrated that the REGy kockout mice exhibited schizophrenia-like phenotypes.Fluorescence quantitative (RT-) PCR and western blot were performed to analyze the expression changes of several interested genes in the brain of the REGy knockout mice. Additionally, the body weight, the morphology, and brain structure were examined in REGy knockout mice. The apoptosis level in the brain was indicated by TUNEL assay. These primary molecular analyses suggested the biological function of REGy in the brain.1. REGy knockout mice breeding and morphology examinationPCR reactions were performed to identify the wildtype, heterozygous and the homozygous of the REGy knockout mice. There was no REGy expression in REGy knockout mice in RNA level. The REGy knockout mice showed smaller body weight comparing to the wildtype mice, which consistent with the previous reports. Additionally, the morphological immune defects were observed in the REGy knockout mice. By Nissl staining, there was no obvious structure change in the brain of the knockout mice. 2. The behavioral analysis of the REGy knockout miceThe phenotypes of REGy deficient mice were analyzed for the first time in a serious of behavioral experiments concerning the spontaneous activity, motor coordination, spatial memory, the anxiety and schizophrenia. The results showed that the REGy knockout mice exhibited the increased spontaneous activity and the moves and time of stereotypies, no change in the motor coordination, no obvious change in spatial memory and anxiety. In addition, the REGy knockout mice showed decreased prepulse inhibition and deficiency in nest-building capability when comparing to the control. All the behavioral experiments demonstrated that the REGy knockout mice exhibited schizophrenia-like phenotypes.3. The primary molecular analysis of the REGy knockout miceFluorescence quantitative (RT-) PCR were performed to analyze the expression levels of several candidate genes. The results showed that in adult REGy knockout mice, NR1, IL-1β, D2 receptor and APC mRNA had no change, while the IGFBP2 mRNA decreased significantly (p<0.05). NR2B mRNA level was slightly decreased in age-dependant manner in REGy knockout mice.In the western blot, APC gene was increased in the forebrain cortex of the REGy knockout mice, which suggests APC may be regulated by REGy in protein level.By TUNEL labeling, no significant apoptosis was found in the brain of REGy knockout mice compared to the control.