van der Hoorn F A, Neupert B
Nucleic Acids Res. 1986 Nov 25;14(22):8771-83. doi: 10.1093/nar/14.22.8771.
Recently we reported that the c-mos(rat) coding region is preceded by sequences (RIS) which repress accumulation of c-mos RNA in the cytoplasm. To investigate the effect of RIS on RNA transcription or processing a retroviral promoter was inserted at different positions relative to RIS. Cotransfection was used to establish cell lines with high copy number of the plasmids and to avoid any selection for c-mos expression or RIS function. Analysis of RNA in the cell lines indicated that RIS does not provide a poly(A) site and allowed characterization of the c-mos(rat) poly(A) site. Surprisingly, RIS contains sequences homologous to elements involved in eucaryotic RNA cleavage/polyadenylation. To determine an effect of RIS on transcription, RNA was elongated in vitro in nuclei isolated from the cell lines and used to analyze the number of RNA polymerase II molecules transcribing different regions of the plasmid. The analysis showed that RIS does not act as transcription termination region.
最近我们报道，c-mos（大鼠）编码区之前的序列（RIS）可抑制c-mos RNA在细胞质中的积累。为了研究RIS对RNA转录或加工的影响，将逆转录病毒启动子插入到相对于RIS的不同位置。采用共转染建立具有高拷贝数质粒的细胞系，以避免对c-mos表达或RIS功能进行任何选择。对细胞系中RNA的分析表明，RIS不提供聚腺苷酸化位点，并可对c-mos（大鼠）聚腺苷酸化位点进行表征。令人惊讶的是，RIS包含与真核RNA切割/聚腺苷酸化相关元件同源的序列。为了确定RIS对转录的影响，在从细胞系中分离的细胞核中体外延长RNA，并用于分析转录质粒不同区域的RNA聚合酶II分子数量。分析表明，RIS不作为转录终止区域。
