Louvion J F, Scholder J C, Pinaud S, Reymond C D
Swiss Institute for Experimental Cancer Research, ISREC, CH-1066 Epalinges.
Nucleic Acids Res. 1991 Nov 25;19(22):6133-8. doi: 10.1093/nar/19.22.6133.
The Dd ras gene produces three transcripts during Dictyostelium development. The largest transcript (L-) can be induced by external addition of cAMP even in cells prevented from aggregating, whereas shorter transcripts (S1- and S2-) expression requires cell aggregate formation. We show the presence of two independent promoters for L- and S-transcripts by deletion analysis of Dd ras fragments fused to CAT reporter genes reintroduced in Dictyostelium. A direct repeat upstream of S-transcript start sites which seems involved in S-promoter function, modulates also L-RNA accumulation. Furthermore removal of sequences between this repeat and the AUG protein start codon reduces the level of L-transcripts in aggregates. This study allowed to uncover the intricate pattern of sequences participating in the regulation of Dd ras expression.
在盘基网柄菌发育过程中，Dd ras基因产生三种转录本。即使在阻止聚集的细胞中，通过外部添加cAMP也可诱导最大的转录本（L-），而较短的转录本（S1-和S2-）的表达则需要细胞聚集体的形成。通过对与重新导入盘基网柄菌的CAT报告基因融合的Dd ras片段进行缺失分析，我们证明了L-和S-转录本存在两个独立的启动子。S-转录本起始位点上游的一个直接重复序列似乎参与S-启动子功能，它也调节L-RNA的积累。此外，去除该重复序列与AUG蛋白起始密码子之间的序列会降低聚集体中L-转录本的水平。这项研究揭示了参与Dd ras表达调控的复杂序列模式。
