在多线染色体中基因激活时染色体蛋白中抗原决定簇的选择性暴露。

Selective exposure of antigenic determinants in chromosomal proteins upon gene activation in polytene chromosomes.

作者信息

Kurth P D, Reisch J C, Bustin M

出版信息

Exp Cell Res. 1983 Feb;143(2):257-69. doi: 10.1016/0014-4827(83)90051-4.

Abstract

The immunological accessibility of the nucleosomal core protein H3 and non-histone protein, HMG-1, was studied in transcriptionally active regions of Chironomus thummi polytene chromosomes. Chromosomal loci were decondensed by incubating isolated salivary glands in various salt solutions or hemolymph. Indirect immunofluorescence studies on these chromosomes using anti-sera to histone H3 revealed that the puffed regions were depleted of fluorescence. The lack of fluorescence could be correlated with the degree of puffing and the level of transcriptional activity. The puffed regions fluoresce after anti-H3 addition if the chromosomes are not cross-linked with formaldehyde, and if prior to the addition of antibodies the chromosomes are treated with 45% acetic acid. We conclude that, whereas histone H3 is present in the puffed regions, its antigenic determinants are sterically hindered by components which are extractable by 45% acetic acid. On the other hand, the antigenic determinants of protein HMG-1 are always available to antibody binding in puffed regions, as well as other chromosomal areas.

摘要

在摇蚊多线染色体的转录活性区域研究了核小体核心蛋白H3和非组蛋白HMG-1的免疫可及性。通过将分离的唾液腺在各种盐溶液或血淋巴中孵育来使染色体位点解聚。使用抗组蛋白H3血清对这些染色体进行间接免疫荧光研究表明，膨松区域荧光缺失。荧光的缺失与膨松程度和转录活性水平相关。如果染色体不与甲醛交联，并且在添加抗体之前用45%乙酸处理染色体，那么在添加抗H3后膨松区域会发出荧光。我们得出结论，虽然组蛋白H3存在于膨松区域，但其抗原决定簇在空间上受到可被45%乙酸提取的成分的阻碍。另一方面，蛋白HMG-1的抗原决定簇在膨松区域以及其他染色体区域总是可与抗体结合。