Lancillotti F, Lopez M C, Alonso C, Stollar B D
J Cell Biol. 1985 May;100(5):1759-66. doi: 10.1083/jcb.100.5.1759.
In polytene chromosomes of Drosophila hydei and D. melanogaster, Z-DNA was identified in varying distribution after different conditions for fixation were used. When salivary glands were fixed and squashed in 50% acetic acid alone, Z-DNA was found in the less dense DNA regions, such as interbands, some puffs, and a few of the less dense bands. Prefixation that combined ethanol and acetic acid exposure led to prominent immunofluorescent staining of the bands, generally but not strictly correlating with the total DNA content. Separate exposure to ethanol and acetic acid did not cause this band to stain, but if residual ethanol was present after ethanol fixation, subsequent exposure to acid did cause it. Under the more selective acid fixation conditions, Z-DNA reactivity was seen in portions of certain ecdysone-inducible puffs in the induced but not in the resting state; in other inducible regions, the Z-DNA immunoreactivity was not changed on induction. Z-DNA was also identified in polytene chromosomes within isolated nuclei that had been frozen and fixed in ethanol without exposure to acid; this Z-DNA was present in regions of low DNA density.
在海德果蝇和黑腹果蝇的多线染色体中，采用不同的固定条件后，Z-DNA呈现出不同的分布。当唾液腺仅用50%乙酸固定并压片时，Z-DNA存在于密度较低的DNA区域，如间带、一些胀泡以及少数密度较低的带中。乙醇和乙酸联合预处理导致带呈现出显著的免疫荧光染色，总体上但并非严格地与总DNA含量相关。单独暴露于乙醇和乙酸不会使这些带染色，但如果乙醇固定后存在残留乙醇，随后暴露于酸中则会使其染色。在更具选择性的酸固定条件下，在某些蜕皮激素诱导的胀泡处于诱导状态而非静止状态的部分区域观察到Z-DNA反应性；在其他诱导区域，诱导后Z-DNA免疫反应性没有变化。在未暴露于酸而在乙醇中冷冻固定的分离细胞核内的多线染色体中也鉴定出了Z-DNA；这种Z-DNA存在于DNA密度较低的区域。
