Assembly properties of lamprey neurofilament subunits and their expression after spinal cord transection.
Assembly properties of lamprey neurofilament subunits and their expression after spinal cord transection.
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七鳃鳗神经丝亚基的组装特性及其在脊髓横断后的表达。
DOI：
10.1002/cne.22673
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Selzer,MichaelE
中科院分区：
文献类型：
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作者：
Zhang,Guixin;Jin,Liqing;Selzer,MichaelE
在哺乳动物中，神经丝（NF）由三种亚基共同组装而成：NFL、NFM和NFH（轻、中和重）。据信七鳃鳗只有一个亚基，NF 180。然而，先前的一项研究表明，NF 180不能自组装，但可以与大鼠NFL共组装，这表明七鳃鳗中存在额外的NF亚基。最近，我们克隆了另外三个NF亚基。这些新的亚基和NF 180现在已经组合转染到SW13cl.2Vim−细胞中，该细胞缺乏内源性胞质中间丝。没有一个亚基可以自我组装在不存在七鳃鳗NFL（L-NFL）的情况下，NF亚基的组合无法形成细丝。组装在28°C下发生，但在37°C下不发生。L-NFL可以与NF 180形成厚的NF束，但不能与NF 132和NF 95形成仅形成细丝状阵列。为了确定丝或束形成所需的NF亚基的哪些部分，我们构建了NF 180的缺失突变体，并将其与L-NFL共转染。与哺乳动物NF一样，只有具有完整头部和核心结构域的构建体才能与L-NFL形成细丝。然而，NF 180的全长需要形成NF束。与NF 180一样，原位杂交表明，L-NFL和NF 132的mRNA在脊髓横断后5周在确定的网状脊髓神经元中下调，但在10周时选择性地在轴突再生概率高的神经元中重新表达。这与NF在轴突再生机制中的可能作用一致。J. Comp.神经元519：3657-3671，2011。© 2011 Wiley利斯公司
In mammals neurofilaments (NF) are formed by coassembly of three subunits: NFL, NFM, and NFH (light, medium, and heavy). It had been believed that lampreys have only one subunit, NF180. However, a previous study showed that NF180 could not self‐assemble but could coassemble with rat NFL, suggesting the existence of additional NF subunits in lamprey. More recently, we cloned three additional NF subunits. These new subunits and NF180 have now been transfected in combinations into SW13cl.2Vim−cells, which lack endogenous cytoplasmic intermediate filaments. None of the subunits could self‐assemble. No combination of NF subunits could form filaments in the absence of lamprey NFL (L‐NFL). Assembly occurred at 28°C, but not at 37°C. L‐NFL could form thick NF bundles with NF180 but not with NF132 and NF95, which formed only fine filamentous arrays. To determine which parts of the NF subunits are required for filament or bundle formation, we constructed deletion mutants of NF180 and cotransfected them with L‐NFL. As with mammalian NF, only constructs with intact head and core domains could form filaments with L‐NFL. However, the full length of NF180 was required to form NF bundles. As with NF180, in situ hybridization indicated that mRNA for L‐NFL and NF132 was downregulated in identified reticulospinal neurons by 5 weeks after spinal cord transection, but was reexpressed at 10 weeks selectively in those neurons whose axons have a high probability of regenerating. This is consistent with a possible role of NFs in the mechanism of axon regeneration. J. Comp. Neurol. 519:3657–3671, 2011. © 2011 Wiley‐Liss, Inc.