Maraldi Nadir M
National Research Council of Italy, Institute of Molecular Genetics, IGM-CNR-IOR, Bologna, Italy.
Biosystems. 2018 Feb;164:68-75. doi: 10.1016/j.biosystems.2017.07.006. Epub 2017 Jul 19.
Unicellular eukaryotes and metazoa present a nuclear envelope (NE) and metazoa express in it one or more lamins that give rise to the nuclear lamina. The expression of different types of lamins is related to the complexity of the organism and the expression of type-A lamins is related to the initial steps of tissue-specific cell differentiation. Several posttranslational modifications characterize the expression of lamin A in the course of cell differentiation, and the alteration of this expression pattern leads to impressive phenotypic diseases that are collectively referred to as laminopathies. This indicates a link between differential lamin A expression and tissue-specific cell commitment, and makes it conceivable that the lamin posttranslational modifications constitute a lamin code, utilized by metazoan cells to induce tissue-specific cell differentiation. Although the rules of this code are not yet deciphered, at the moment, the presence of adaptors, represented by NE transmembrane proteins (NETs), and of effectors, constituted by epigenetic repressors that modulate chromatin arrangement and gene expression, strongly supports the possibility that the rules of lamin modification represent one of the organic codes that characterize cell evolution.
单细胞真核生物和后生动物具有核膜（NE），而后生动物在核膜中表达一种或多种形成核纤层的核纤层蛋白。不同类型核纤层蛋白的表达与生物体的复杂性相关，A型核纤层蛋白的表达与组织特异性细胞分化的初始步骤有关。几种翻译后修饰是细胞分化过程中核纤层蛋白A表达的特征，这种表达模式的改变会导致令人印象深刻的表型疾病，统称为核纤层蛋白病。这表明核纤层蛋白A的差异表达与组织特异性细胞定向之间存在联系，并且可以设想核纤层蛋白的翻译后修饰构成了一种核纤层蛋白编码，后生动物细胞利用它来诱导组织特异性细胞分化。尽管目前尚未破译该编码的规则，但目前由核膜跨膜蛋白（NETs）代表的衔接子和由调节染色质排列和基因表达的表观遗传阻遏物构成的效应子的存在，有力地支持了核纤层蛋白修饰规则代表细胞进化特征的有机编码之一的可能性。
