Patel N T, Holoubek V
Chem Biol Interact. 1981 May;35(2):129-37. doi: 10.1016/0009-2797(81)90137-x.
In the liver of rats fed the azocarcinogen 3'-methyl-4-dimethylaminoazobenzene (3'MeDAB) reiterated RNA sequence transcribed from middle repetitive DNA are released into the cytoplasm. The same repetitive nucleotide sequences can be isolated from the chromatin of the liver of control animals in the form of metabolically highly active, 13 000 daltons RNA. This small, chromatin-associated RNA originates from nuclear RNA larger than 10 S. The discontinuation of the feeding of the azocarcinogen will not stop the release of the nuclear reiterated RNA sequences into the cytoplasm. The repetitive sequences of nuclear RNA which are released into the cytoplasm in animals fed the azocarcinogen can no longer be found in the chromatin in the form of small RNA molecules. The results can be explained by the assumption that the reiterated RNA sequences are involved in the upholding of RNA processing. A cell-specific processing of RNA will be maintained by the interaction of reiterated RNA fragments from already processed RNA with the reiterated complementary sequences on RNA yet to be processed. Existence of such a feed-back circuit would make it possible to explain how a temporary interference of the azocarcinogen with RNA processing will result in the disappearance of specific reiterated RNA sequences from the chromatin. It could also explain the continuation of the release of the same repeated RNA sequences into the cytoplasm as part of larger RNA molecules even after the removal of the carcinogen.
在喂食偶氮致癌物3'-甲基-4-二甲基氨基偶氮苯（3'MeDAB）的大鼠肝脏中，从中度重复DNA转录而来的重复RNA序列被释放到细胞质中。相同的重复核苷酸序列可以从对照动物肝脏的染色质中以代谢高度活跃的13000道尔顿RNA的形式分离出来。这种与染色质相关的小RNA起源于大于10S的核RNA。停止喂食偶氮致癌物不会阻止核重复RNA序列释放到细胞质中。在喂食偶氮致癌物的动物中释放到细胞质中的核RNA重复序列，在染色质中再也找不到以小RNA分子形式存在的了。这些结果可以通过假设重复RNA序列参与RNA加工的维持来解释。RNA的细胞特异性加工将通过已加工RNA的重复RNA片段与待加工RNA上的重复互补序列的相互作用来维持。这种反馈回路的存在将有可能解释偶氮致癌物对RNA加工的暂时干扰如何导致染色质中特定重复RNA序列的消失。它还可以解释即使在去除致癌物后，相同重复RNA序列作为较大RNA分子的一部分继续释放到细胞质中的现象。
