丛枝异水霉中的核糖体RNA顺反子。

Ribosomal RNA cistrons in Allomyces arbuscula.

作者信息

Ojha M, Turian G

出版信息

Biochim Biophys Acta. 1977 Oct 18;478(4):392-406. doi: 10.1016/0005-2787(77)90095-8.

Abstract

Bulk and nuclear DNA have been fractionated by preparative neutral CsCl equilibrium density gradient centrifugation and each fraction hybridized to labeled rRNA (25 + 18 S). The cistrons coding for rRNA appeared on the light side of the main peak. Hybridization of the nuclear DNA fractionated by preparative Ag+-Cs2SO4 gradients at different pHs showed that the banding profile did not change as compared to the CsCl pattern. In Hg2+-Cs2SO4 gradients, however, the peak of the fRNA-DNA hybrids shifted on the heavier side of the profile. This indicates that the ribosomal RNA cistrons in Allomyces are A-T-rich. Hybridization with homologous rRNA showed that, at saturation, 3.25% of the DNA is complementary to rRNA. With the genome size of 1.7-10(10) daltons, the multiplicity of rRNA cistrons has been found to be close to 270.

摘要

通过制备性中性氯化铯平衡密度梯度离心法对总DNA和核DNA进行了分级分离，并将每个级分与标记的rRNA（25 + 18 S）杂交。编码rRNA的顺反子出现在主峰的轻侧。通过在不同pH值下用制备性银离子 - 硫酸铯梯度分级分离的核DNA进行杂交，结果表明与氯化铯模式相比，条带图谱没有变化。然而，在汞离子 - 硫酸铯梯度中，fRNA - DNA杂交体的峰在图谱较重的一侧发生了移动。这表明异水霉中的核糖体RNA顺反子富含A - T。与同源rRNA杂交表明，在饱和时，3.25%的DNA与rRNA互补。鉴于基因组大小为1.7 - 10(10)道尔顿，已发现rRNA顺反子的重复数接近270。