Mott M R, Burnett E J, Hill R J
J Cell Sci. 1980 Oct;45:15-30. doi: 10.1242/jcs.45.1.15.
Drosophila polytene chromosomes prepared by a new micromanipulative procedure, which avoids acid squashing, have been examined at the ultrastructural level in the electron microscope. Puffs at 2B, 68C, 74EF, 75B and 85EF, have been examined in some detail, along with the chromocentre and various interbands. The ultrastructure of these chromosomes, which have never been exposed to acid protein denaturants, compares favourably with that of classical acid-fixed specimens. Ribonucleoprotein particles in puffs are seen to be organized in linear arrays and evidence is adduced for looped transcription units. Particles with characteristic sizes and morphologies are observed near the chromocentre, in puffs and in interbands. In interbands RNP particles and 'superbead'-like chromatin particles may be distinguished. Drosophila polytene chromosomes isolated by micro-manipulation should prove useful for the localization of native chromosomal proteins at an ultrastructural level.
通过一种避免酸压片的新显微操作程序制备的果蝇多线染色体，已在电子显微镜下进行了超微结构水平的检查。对2B、68C、74EF、75B和85EF处的胀泡，以及染色中心和各种间带进行了较为详细的检查。这些从未接触过酸性蛋白质变性剂的染色体的超微结构，与经典酸固定标本的超微结构相比毫不逊色。胀泡中的核糖核蛋白颗粒呈线性排列，并有证据表明存在环状转录单位。在染色中心附近、胀泡中和间带中观察到具有特征尺寸和形态的颗粒。在间带中，可以区分核糖核蛋白颗粒和“超级珠”状染色质颗粒。通过显微操作分离的果蝇多线染色体，应可证明在超微结构水平上对天然染色体蛋白质的定位很有用。
