Xiao Junhua, Neylon Craig B, Hunne Billie, Furness John B
Department of Anatomy and Cell Biology, and Centre for Neuroscience, University of Melbourne, Parkville, Australia.
Anat Rec A Discov Mol Cell Evol Biol. 2003 Aug;273(2):671-6. doi: 10.1002/ar.a.10072.
Oligophrenin-1 is a RhoGTPase-activating protein (RhoGAP) that is involved in the regulation of shape changes in dendritic spines, and outgrowth of axons and dendrites in the brain. These changes in neuronal morphology are central to the mechanisms of plasticity, learning, and memory. Although the enteric nervous system also exhibits long-term changes in neuronal function, the expression and involvement of oligophrenin-1 has not previously been investigated. We show by RT-PCR analysis that oligophrenin-1 mRNA is expressed in the myenteric plexus (MP) of the guinea pig ileum. Sequencing of RT-PCR products showed that guinea pig oligophrenin-1 mRNA is 98% and 87% homologous to human and mouse oligophrenin-1, respectively, except that a 42 bp sequence is absent from the guinea pig mRNA. This 42 bp sequence codes for a sequence of 14 amino acids located near the carboxy-terminal end of the RhoGAP domain in the human sequence. An antibody that recognizes human oligophrenin-1 identified a 91 kDa protein band in rat and mouse brain lysates and in guinea pig sciatic nerve, and a 36 kDa protein band in both purified enteric ganglion cell and brain lysate from guinea pig. Oligophrenin-1 is localized specifically to neurons and varicose axons in the MPs and submucosal plexuses (SMPs) of the guinea pig and rat, but is not detectable in glial cells, smooth muscle, or other cell types. These findings indicate that oligophrenin-1 is expressed in the enteric nervous system, where it may regulate morphological changes in axons and dendrites, and thus modulate neuronal connectivity.
少突素-1是一种RhoGTP酶激活蛋白（RhoGAP），参与调节树突棘的形态变化以及大脑中轴突和树突的生长。神经元形态的这些变化是可塑性、学习和记忆机制的核心。尽管肠神经系统在神经元功能方面也表现出长期变化，但少突素-1的表达和作用此前尚未得到研究。我们通过逆转录聚合酶链反应（RT-PCR）分析表明，少突素-1 mRNA在豚鼠回肠的肌间神经丛（MP）中表达。RT-PCR产物测序显示，豚鼠少突素-1 mRNA与人类和小鼠少突素-1的同源性分别为98%和87%，只是豚鼠mRNA中缺少一个42 bp的序列。这个42 bp的序列编码一段位于人类序列中RhoGAP结构域羧基末端附近的14个氨基酸序列。一种识别人类少突素-1的抗体在大鼠和小鼠脑裂解物以及豚鼠坐骨神经中鉴定出一条91 kDa的蛋白条带，在豚鼠纯化的肠神经节细胞和脑裂解物中鉴定出一条36 kDa的蛋白条带。少突素-1特异性定位于豚鼠和大鼠MP和黏膜下神经丛（SMP）中的神经元和曲张轴突，但在胶质细胞、平滑肌或其他细胞类型中未检测到。这些发现表明少突素-1在肠神经系统中表达，它可能在其中调节轴突和树突的形态变化，从而调节神经元的连接。
