Gordon J S, Rosenfeld B I, Kaufman R, Williams D L
Biochemistry. 1980 Sep 16;19(19):4395-402. doi: 10.1021/bi00560a003.
The quantitative tissue specificity of the high mobility group (HMG) chromosomal proteins was investigated. Perchloric acid (PCA) extracts of four different chicken tissues and erythrocytes contained three proteins which comigrated on NaDodSO4-polyacrylamide gels with the HMG's 1,2, and E from erythrocyte nuclei. These three HMG's from embryonic skeletal muscle and erythrocytes also comigrated on two-dimensional gels, employing an acid-urea system in the first dimension and an NaDodSO4 system in the second. Interpretation of the two-dimensional gels suggested that the two low molecular weight proteins of this triplet arose from the HMG 2 band of the acid-urea gels. These have been designated HMG 2A and HMG 2B. Three proteins of similar molecular weights were also found in the PCA extracts of calf thymus. They were arranged in a similar but not identical pattern on two-dimensional gels. Thus, these three HMG's appear to be neither tissue nor species specific. In addition, the 2.0% PCA extracts of all chicken tissues examined contain a 38 000-dalton (38K) nuclear protein which coisolates with the HMG's. These four proteins are found in different relative amounts in each of the four chicken tissues and erythrocytes. They are found in the same relative amounts, however, in embryonic skeletal muscles from different chicken strains with widely different highly repetitive sequence content, suggesting that none of these individual proteins is selectively localized to constitutive heterochromatin. The quantitative tissue specificity of the HMG's and the 38K protein, however, suggests that they may participate in regulating cell-specific gene expression.
对高迁移率族（HMG）染色体蛋白的定量组织特异性进行了研究。四种不同鸡组织和红细胞的高氯酸（PCA）提取物含有三种蛋白质，它们在十二烷基硫酸钠-聚丙烯酰胺凝胶上与红细胞核中的HMG 1、2和E共迁移。来自胚胎骨骼肌和红细胞的这三种HMG在二维凝胶上也共迁移，第一维采用酸-尿素系统，第二维采用十二烷基硫酸钠系统。二维凝胶的分析表明，该三联体中的两种低分子量蛋白质来自酸-尿素凝胶的HMG 2带。这些已被命名为HMG 2A和HMG 2B。在小牛胸腺的PCA提取物中也发现了三种分子量相似的蛋白质。它们在二维凝胶上以相似但不完全相同的模式排列。因此，这三种HMG似乎既不是组织特异性的也不是物种特异性的。此外，所有检测的鸡组织的2.0%PCA提取物都含有一种38000道尔顿（38K）的核蛋白，它与HMG共分离。这四种蛋白质在四种鸡组织和红细胞中的相对含量各不相同。然而，在具有广泛不同高度重复序列含量的不同鸡品系的胚胎骨骼肌中，它们的相对含量相同，这表明这些单个蛋白质中没有一种选择性地定位于组成型异染色质。然而，HMG和38K蛋白的定量组织特异性表明它们可能参与调节细胞特异性基因表达。
