Doenecke D, Tönjes R, Kress H
Institut für Biochemie, Georg-August-Universität Göttingen, Federal Republic of Germany.
Adv Enzyme Regul. 1988;27:107-20. doi: 10.1016/0065-2571(88)90012-x.
The patterns of chromosomal proteins reflect in many cases the functional state of the respective cell type. The H1 histone group is particularly important in this respect, since these histones are involved in the higher order chromatin organization above the level of chains of nucleosomes. In mammals, the H1 histone family comprises at least five main subtypes (H1a-H1e), a testicular variant (H1t) and, thirdly, a subtype H1(0), which is found only in terminally differentiated cells. The H1(0) variant is structurally related to the avian red blood cell specific histone H5, which was the basis for our recent isolation of the human H1(0) gene. Changes of H1 histone patterns may be crucial events in modulating local chromatin arrangements, since the formation of higher order chromatin structures depends on a cooperative interaction of the H1 histones. Variations in their patterns can be studied in vivo during several developmental processes (such as spermatogenesis, erythropoiesis, maturation of several cell types) or in vitro in several tumor cell lines upon treatment with several inducers or upon inhibition of cell division. The differential regulation of the individual H1 subtypes is reflected in the gene and mRNA structures coding for the respective proteins. The cell cycle regulated histones are mostly encoded by non-polyadenylated mRNAs, whereas H5 as well as H1(0) mRNA shows a poly(A) tail at its 3' end. In conclusion, gene activity may not only be controlled at the level of RNA polymerases and their regulatory transcription factors. The varied patterns of chromosomal proteins at different stages during development and differentiation suggest that the local or overall organization of chromatin plays an additional role in these regulatory programs. Hence, the analysis of variations in patterns of chromosomal proteins is an integral part of the investigation of gene regulation mechanisms.
在许多情况下，染色体蛋白的模式反映了相应细胞类型的功能状态。在这方面，H1组蛋白尤为重要，因为这些组蛋白参与了核小体链水平以上的高级染色质组织。在哺乳动物中，H1组蛋白家族至少包括五个主要亚型（H1a - H1e）、一个睾丸变体（H1t），以及仅在终末分化细胞中发现的亚型H1(0)。H1(0)变体在结构上与鸟类红细胞特异性组蛋白H5相关，这是我们最近分离人类H1(0)基因的基础。H1组蛋白模式的变化可能是调节局部染色质排列的关键事件，因为高级染色质结构的形成依赖于H1组蛋白的协同相互作用。它们模式的变化可以在体内的几个发育过程（如精子发生、红细胞生成、几种细胞类型的成熟）中进行研究，或者在体外的几种肿瘤细胞系中，在用几种诱导剂处理或抑制细胞分裂后进行研究。各个H1亚型的差异调节反映在编码相应蛋白质的基因和mRNA结构中。细胞周期调控的组蛋白大多由非聚腺苷酸化的mRNA编码，而H5以及H1(0) mRNA在其3'端显示有聚(A)尾。总之，基因活性可能不仅在RNA聚合酶及其调节转录因子水平受到控制。在发育和分化的不同阶段，染色体蛋白的多样模式表明染色质的局部或整体组织在这些调节程序中发挥着额外的作用。因此，分析染色体蛋白模式的变化是基因调控机制研究不可或缺的一部分。
