Glass W F, Briggs J A, Meredith M J, Briggs R C, Hnilica L S
J Biol Chem. 1985 Feb 10;260(3):1895-900.
A significant increase in the molecular weights of lamin A and more so of lamin C was observed when isolated Novikoff hepatoma chromatin was incubated in the presence of Ca2+. This increase did not occur to any significant degree in similar preparations of normal rat liver nuclei. Although detectable in Coomassie Brilliant Blue stained gels, this increase to a higher molecular weight (by approximately 2000 Mr) was much more visible when the electrophoretically separated lamins were transferred to nitrocellulose sheets and stained (using peroxidase-antiperoxidase) with polyclonal antiserum to the three major lamin proteins. This modification could also be induced when whole Novikoff hepatoma cell lysates were incubated in the presence of calcium. Again, this change did not occur in normal rat liver cells treated in the same manner. Further analysis has provided evidence that this modification is most likely mediated by the transaminating activity of an intrinsic nuclear transglutaminase forming a cross-link between the affected lamins and an unknown low molecular weight (approximately equal to 2000 Mr) moiety.
当分离出的诺维科夫肝癌染色质在Ca2+存在的情况下孵育时，观察到核纤层蛋白A的分子量显著增加，核纤层蛋白C的增加更为明显。在正常大鼠肝细胞核的类似制剂中，这种增加并未达到任何显著程度。尽管在考马斯亮蓝染色的凝胶中可检测到，但当将经电泳分离的核纤层蛋白转移到硝酸纤维素膜上，并用针对三种主要核纤层蛋白的多克隆抗血清（使用过氧化物酶-抗过氧化物酶）染色时，这种分子量增加到更高水平（约2000 Mr）的情况更为明显。当整个诺维科夫肝癌细胞裂解物在钙存在的情况下孵育时，也可诱导这种修饰。同样，以相同方式处理的正常大鼠肝细胞中未出现这种变化。进一步分析提供了证据，表明这种修饰最有可能由一种内在的核转谷氨酰胺酶的转氨活性介导，该酶在受影响的核纤层蛋白与一个未知的低分子量（约等于2000 Mr）部分之间形成交联。
