Analysis of cell transformation by small molecular weight RNA.

本研究利用从小鼠胸腺瘤细胞中提取的小分子RNA进行体外细胞转化研究。将负责转化活性的RNA命名为转化RNA。用异硫氰酸胍(GTC)-热酚提取法从化学诱导的小鼠淋巴瘤细胞中提取细胞总RNA。转化RNA经2次20%天然聚丙烯酰胺凝胶或3次10%变性聚丙烯酰胺凝胶电泳法纯化。将该RNA导入大鼠成纤维细胞系3Y1细胞。当3Y1细胞不连续传代时，43~53天出现转化细胞灶。用软琼脂集落形成法检测3Y1细胞的转化表型，并用[3‘-32P]RNA进行直接化学测序，以确定转化RNA的纯度。读取了该RNA的110个碱基的部分序列。结果表明，转化后的RNA序列与一种小的核RNA，即U5 RNA有显著的同源性。

This study is focused on in vitro cell transformation with small molecular weight RNA extracted from mouse thymoma cells. The RNA responsible for transforming activity was designated as transforming RNA. Total cellular RNA was obtained from chemically-induced lymphoma cells in mice by Guanidinium isothiocyanate (GTC)-hot phenol extraction. Transforming RNA was purified by the two cycles of electrophoresis through 20% native polyacrylamide gels or three cycles of electrophoresis through 10% denaturing polyacrylamide gels. The RNA was transfected into rat fibroblastic cell line, 3Y1 cells. When 3Y1 cells transfected with the RNA was maintained without serial passage, transformed cell foci appeared at the latency of 43 to 53 days. The transformed phenotype of 3Y1 cells was confirmed by colony formation of the cells in soft agar.In order to confirm the purity of transforming RNA thus isolated, the RNA was sequenced by the direct chemical method using [3'-32P]RNA. The partial 110 bases sequence of the RNA was read. It was revealed that transforming RNA sequence had remarkable homology to one of the small nuclear RNA, namely U5 RNA.