Way J, Hellmich M R, Jaffe H, Szaro B, Pant H C, Gainer H, Battey J
Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
Proc Natl Acad Sci U S A. 1992 Aug 1;89(15):6963-7. doi: 10.1073/pnas.89.15.6963.
Previous studies have shown that two low molecular-weight neurofilament (NF) proteins (NF-60 and NF-70) from the squid Loligo pealei are translated from mRNAs that are splice variants of a single squid NF gene. In this study, we report the isolation and characterization of cDNA clones encoding a high-molecular-weight squid NF protein (NF-220), the mRNA of which derives from the same squid NF gene. All three proteins are identical in their amino-terminal and lamin-like rod domains but differ in their carboxyl-terminal tail regions. In contrast to the short tail domains of NF-60 and NF-70, the NF-220 protein has a longer tail domain containing an acidic cluster of amino acids immediately followed by repeated copies of the sequence motif Lys-Ser-Pro. The Lys-Ser-Pro domain is similar to that of mammalian medium NF (NF-M) and high NF (NF-H) proteins, where the serines are highly phosphorylated. Except for these Lys-Ser-Pro motifs, there is surprisingly little structural similarity between the squid NF-220 protein and mammalian NF-M and NF-H proteins. Furthermore, the location of introns in squid NF-220 protein shows that it is more closely related to nuclear lamins and type III intermediate-filament proteins than to vertebrate NF proteins.
先前的研究表明，来自枪乌贼的两种低分子量神经丝（NF）蛋白（NF-60和NF-70）是由单个枪乌贼NF基因的剪接变体mRNA翻译而来的。在本研究中，我们报告了编码一种高分子量枪乌贼NF蛋白（NF-220）的cDNA克隆的分离和特性，其mRNA来源于同一个枪乌贼NF基因。这三种蛋白在其氨基末端和层粘连蛋白样杆状结构域中是相同的，但在其羧基末端尾部区域有所不同。与NF-60和NF-70的短尾部结构域相反，NF-220蛋白具有更长的尾部结构域，该结构域包含一个酸性氨基酸簇，紧接着是序列基序Lys-Ser-Pro的重复拷贝。Lys-Ser-Pro结构域与哺乳动物中分子量NF（NF-M）和高分子量NF（NF-H）蛋白的结构域相似，其中丝氨酸高度磷酸化。除了这些Lys-Ser-Pro基序外，枪乌贼NF-220蛋白与哺乳动物NF-M和NF-H蛋白之间的结构相似性惊人地少。此外，枪乌贼NF-220蛋白中内含子的位置表明，它与核纤层蛋白和III型中间丝蛋白的关系比与脊椎动物NF蛋白的关系更密切。
