SRS－淋巴瘤小鼠淋巴细胞染色质理化性质的研究

Chemical and physical nature of active chromatin in SRS-lymphoma mouse lymphocyte

本实验对正常及ＳＲＳ－淋巴瘤小鼠淋巴细胞染色质进行了化学组分、ＤＮａｓｅⅠ有限度消化、染色质附着蛋白释放，热变性的对比分析。结果表明：（１）ＳＲＳ－淋巴瘤细胞染色质的非组蛋白（ｎｏｎ－ｈｉｓｔｏｎｅｃｈｒｏｍｏｓｏｍａｌｐｒｏｔｅｉｎｓ，ＮＨＣＰ）和ＲＮＡ高于正常细胞，提示随着肿瘤的发生染色质转录活性和与转录相关的ＮＨＣＰ呈升高趋势；（２）ＳＲＳ－淋巴瘤细胞染色质的ＤＮａｓｅⅠ消化率明显高于正常淋巴细胞，提示肿瘤细胞含有较多优先被核酸酶消化的活性染色质；（３）ＳＲＳ－淋巴瘤细胞较正常淋巴细胞蛋白释放量明显升高，提示参与活性染色质结合的ＮＨＣＰ与染色质活性位点及转录活性有密切相关；（４）ＳＲＳ－淋巴瘤细胞染色质比正常淋巴细胞增色效应明显，提示肿瘤细胞比正常细胞染色质结构疏松。

Chromatin was extracted from SRS-lymphoma and normal mouselymphocyte by Chiu′s method. Results obtained 1.Their chromatin nuclear acid had notmuch difference, but the values of NHCP/HP and RNA/DNA in mouse SRS-lymphomacells were higher than those in normal lymphocyte.These results showed that the NHCPincrcased significantly with tumor development;2.The ratio of DNase I limited digestionof chromatin in SRS-lymphoma mouse cells were higher than that in normal mouselymphocyte. The results showed that chromatin of SRS-lymphoma mouse cells containedmore DNase I hypersensitive sites than normal mouse lymphocyte;3.The amount ofprotein released clromatin from SRS-lympnolna mouse cells were higher than that fromnormal mouse lymphocyte during DNase I digestion. The results showed that the NHCPspecifically binded active chromatin was closely related to the increasing of active sitesand transcriptional activity of chromatin;4.The thermal denaturation curve showed that thehyperchromic effect of SRS-lylnphoma chromatin was higher than that of normal lymphocyte,the result suggested that the chromatin structure was much loose in SRS-lymphoma cells.