正常及白血病小鼠白细胞染色质和DNA的酶切分析

 本文应用的核酸酶为DNaseⅡ、微球菌核酸酶与限制性内切核酸酶BstNI、EcoRⅡ、HpaⅡ和MspⅠ,将它们作用于正常小鼠615和可移植性白血病小鼠L7712脾脏白细胞染包质及其DNA,根据酶切电泳谱及水解动力学分析表明:1.白血病小鼠染色质相对正常小鼠染色质易被DNaseⅡ微球菌核酸酶水解;2.白血病小鼠染色质比正常小鼠者易被MspⅠ水解,但其DNA的MspⅠ酶切电泳谱无明显差别;3.白血病小鼠染色质及其DNA较正常小鼠染色质及其DNA易被EcoRⅡ水解。这些观察说明,白血病小鼠脾脏白细胞染色质有较活跃的构象状态;其染色质DNA的CCATGC区段内有较低的甲基化程度。

A COMPARISON OF THE DIGESTION OF CHROMATIN FROM NORMAL AND LEUKMEIA MOUSE LEUCOCYTES WITH DNases

Limited nuclease digestion of chromatin has been proved to be useful for recognition of the conformation and the structure of chromatin.In this paper we have compared the enzymatic digestion patterns of chromatin and its DNA of spleen leucocytes from normal and leukemia mice.We found that chromatin from leukemic mouse leucocytes is more susceptible to DNase Ⅱ then chromatin from normal cells.The chromatin from leukemic mouse leucocytes was also more easily digested by Msp Ⅰ than that from normal mouse leucocytes, but the digestion patterns of the chromatin DNA from both were about the same. We also found chromatin from leukemic mouse leucocytes, were more susceptible to digestion by Eco RⅡ.Our observations suggested that more active conformation may exist in chromatin of spleen leucocytes from leukemic mouse.