Nuclear membranes and plasma membranes from hen erythrocytes. I. Isolation, characterization, and comparison.
Nuclear membranes and plasma membranes from hen erythrocytes. I. Isolation, characterization, and comparison.
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母鸡红细胞的核膜和质膜。
DOI：
10.1016/s0021-9258(18)62280-x
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发表时间：
1971
期刊：
影响因子：
--
通讯作者：
W. Franke
中科院分区：
文献类型：
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作者：
H. Zentgraf;B. Deumling;E. Jarasch;W. Franke
鸟类红细胞提供了一个由两种膜组成的细胞系统，即质膜和核膜。根据形态计量学计算，这两种膜几乎以1:1的膜表面比例存在。与其他类型的膜污染是优先排除在这个细胞。采用高速旋转刀均质结合差速离心和梯度离心的非洗涤方法分离纯化的质膜和核包膜。核蛋白经过高盐提取和声波振荡，有或没有dna酶的额外消化，核膜与其他核成分分离。纯度和结构完整性的分数显示在电子显微镜下。核膜（p422= 1.20）和质膜（p422= 1.14）的浮力密度不同。给出了完整细胞和细胞核、核膜和质膜组分的大体组成，包括脂质、磷脂、胆固醇、蛋白质、RNA和DNA，以及相应的回收率。核膜与质膜的不同之处在于，核膜的胆固醇-磷脂比要低得多，蛋白质含量更高，并且有一定量的DNA牢牢地附着在核膜上。总的来说，鸟类红细胞膜的性质与非核红细胞的性质一致。在检测的酶中，质膜显示atp酶活性，包括一种对瓦苦因敏感的酶。另一方面，核膜部分几乎没有atp酶活性，但确实显示出典型的“内质网型酶”nadh细胞色素还原酶的活性。虽然核片段显示出NAD+焦磷酸化酶的强富集，但这种活性在质膜和核膜中没有发现，这表明核膜片段中存在低程度的核质蛋白污染。本文结合细胞膜→质膜极化和多样性的概念，讨论了这种“死角分化”细胞类型仅有的两种膜系统之间的差异。
The bird erythrocyte provides a cell system which comprises only two sorts of membranes, namely the plasma membrane and the nuclear envelope. As calculated morphometrically, both of these membranes are present in an almost 1:1 membrane surface ratio. Contamination with other types of membranes isa prioriexcluded in this cell. Purified fractions of plasma membranes and nuclear envelope membranes were isolated by using nondetergent methods, in which high speed rotating knife homogenization is combined with differential and gradient centrifugation steps. Nuclear membranes were separated from other nuclear constituents after high salt extraction of nucleoproteins and sonic oscillation, with or without an additional digestion with DNase. Purity and structural integrity of the fractions are shown in electron micrographs. The buoyant densities of nuclear membranes (p422= 1.20) and plasma membranes (p422= 1.14) are different. The gross compositions of intact cells and the nuclei, nuclear membrane, and plasma membrane fractions, with respect to lipids, phospholipids, cholesterol, protein, RNA, and DNA, are given, as well as corresponding recoveries. The nuclear membrane is distinct from the plasma membrane as shown in a much lower cholesterol-phospholipid ratio, in a higher content in protein, and a certain amount of DNA remaining firmly attached to it. In general, the properties of the bird erythrocyte plasma membrane agree with those known from the non-nucleated erythrocytes. Among the enzymes examined, the plasma membrane showed ATPase activity, including a ouabain-sensitive one. On the other hand, the nuclear membrane fraction was almost devoid of ATPase activity, but did show the activity of a typical "endoplasmic reticulum type enzyme," the NADH-cytochromecreductase. While the nuclear fraction demonstrated a strong enrichment for NAD+pyrophosphorylase, this activity was not found in the plasma membranes or in the nuclear membranes, which indicates the low degree of nucleoplasmic protein contamination present in the nuclear membrane fraction. The differences between the only two membrane systems of this "dead end differentiated" cell type are discussed in context with the present concepts on the cytomembrane → plasma membrane polarization and diversity.