牛肾细胞染色体中染色质纤维的包装及RNP的分布

应用培养的牛肾（ＢＫ）细胞及分离的ＢＫ细胞染色体做常规透射电镜样品，经表面舒展技术和临界点干燥制备ＢＫ细胞染色体的扫描电镜样品，并结合电镜细胞化学研究了ＢＫ染色质纤维的包装及核糖核蛋白（ＲＮＰ）的分布。观察到ＢＫ染色体具有多级双股螺旋结构。在染色体横切面中，可见染色体中央有一低电子密度的无染色质区，该区内有大量ＲＮＰ物质。在染色质区ＲＮＰ较少，分布在染色质纤维间，与中央轴区的ＲＮＰ相连续，表明ＲＮＰ在染色体中呈不均匀分布。

Packing of the Chromatin Fibers and the Distribution of RNP in BK Chromosomes

The packing of the chromatin fibers and the distribution of RNP in bovine kidney (BK)chromosomes were studied by the combination of transmission,scanning electronic microscopy (TEM, SEM) and cytochemical electronic microscopy (CCEM). The results showed that BK chromosomes reveal a multiple double strand helical structure. The central axial area of each chromatid is a low electronic density region or chromatin free compartment, in which there are lots of RNP. In the peripheral chromatin region the RNP is distributed among the chromatin fibers and continued with that of the central region. The density of the central RNP is more than that of the peripheral RNP, which indicates that RNP is not uniformly distributed in chromosome.This project supported by National Natural Science Foundation of China.