Effects of overexpression of Sim2 on spatial memory and expression of synapsin I in rat hippocampus.
The single-minded 2 gene (Sim2) plays a crucial role in the mental retardation of Down Syndrome (DS). To explore how Sim2 influences spatial memory, a DNA plasmid-encoding mouse Sim2 (mSim2) wrapped with liposome was bilaterally injected into the hippocampus of rats. The effect of overexpressing mSim2 on spatial learning was determined by a Morris water maze task. The expression of synapsin I was detected by reverse transcriptional-polymerase chain reaction (RT-PCR) analysis and immunohistochemistry, respectively. The phosphosynapsin was also examined by immunohistochemistry. As demonstrated by RT-PCR, mSim2 was overexpressed in the hippocampus of rats, and pcDNA3/mSim2-transfected rats showed longer latency to find the hidden platform compared with pcDNA3-transfected rats (P<0.05). Synapsin I mRNA and protein expression were decreased significantly by mSim2 transfection, as demonstrated by RT-PCR and immunohistochemistry. Moreover, the expression profile of phosphosynapsin was similar to that of synapsin I. So it is concluded that Sim2 could impair the ability of learning and memory by inhibiting synaptic plasticity, and may play a crucial role in the pathogenesis of DS.
Meng
Xianfang
X
Department of Neurobiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, China.
Peng
Bin
B
Shi
Jing
J
Zheng
Yao
Y
Chen
Hao
H
Zhang
Jing
J
Li
Lingli
L
Zhang
Chun
C
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D003001:Cloning, Molecular; D004314:Down Syndrome / Q000209:etiology / Q000235:genetics; D004622:Embryo, Mammalian / Q000378:metabolism; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D018782:Maze Learning; D008568:Memory / Q000502:physiology*; D051379:Mice; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013028:Space Perception / Q000502:physiology; D016704:Synapsins / Q000378:metabolism*; D014162:Transfection
D051792:Basic Helix-Loop-Helix Proteins; D012333:RNA, Messenger; D016704:Synapsins; C486578:Sim2 protein, mouse