在文昌鱼中枢神经系统中存在多种神经丝亚单位。
Multiple neurofilament subunits are present in lamprey CNS.
机构信息
Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, 3500 N. Broad Street, Philadelphia, PA 19140-5104, USA.
出版信息
Brain Res. 2011 Jan 25;1370:16-33. doi: 10.1016/j.brainres.2010.11.037. Epub 2010 Dec 16.
In mammals, there are three neurofilament (NF) subunits (NF-L, NF-M, and NF-H), but it was thought that only a single NF, NF180, exists in lamprey. However, NF180 lacked the ability to self-assemble, suggesting that like mammalian NFs, lamprey NFs are heteropolymers, and that additional NF subunits may exist. The present study provides evidence for the existence of a lamprey NF-L homolog (L-NFL). Genes encoding two new NF-M isoforms (NF132 and NF95) also have been isolated and characterized. With NF180, this makes three NF-M-like isoforms. In situ hybridization showed that all three newly cloned NFs are expressed in spinal cord neurons and in spinal-projecting neurons of the brainstem. Like NF180, there were no KSP multiphosphorylation repeat motifs in the tail regions of NF132 or NF95. NF95 was highly identical to homologous parts of NF180, sharing 2 common pieces of DNA with it. Northern blots suggested that NF95 may be expressed at very low levels in older larvae. The presence of L-NFL in lamprey CNS may support the hypothesis that as in mammals, NFs in lamprey are obligate heteropolymers, in which NF-L is a required subunit.
在哺乳动物中，有三种神经丝（NF）亚基（NF-L、NF-M 和 NF-H），但人们认为在七鳃鳗中只存在一种 NF，即 NF180。然而，NF180 缺乏自我组装的能力，这表明与哺乳动物的 NF 一样，七鳃鳗的 NF 是异源多聚体，可能存在其他 NF 亚基。本研究为存在七鳃鳗 NF-L 同源物（L-NFL）提供了证据。还分离和表征了编码两种新的 NF-M 同工型（NF132 和 NF95）的基因。加上 NF180，这使得三种 NF-M 样同工型。原位杂交显示，所有三种新克隆的 NF 都在脊髓神经元和脑干投射到脊髓的神经元中表达。与 NF180 一样，NF132 或 NF95 的尾部区域没有 KSP 多磷酸化重复基序。NF95 与 NF180 的同源部分高度一致，与它共享 2 个共同的 DNA 片段。Northern blot 表明，NF95 可能在较老的幼虫中以非常低的水平表达。L-NFL 在七鳃鳗中枢神经系统中的存在支持了这样一种假说，即在哺乳动物中，七鳃鳗的 NF 是必需的异源多聚体，其中 NF-L 是必需的亚基。
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