Cohen S M, Cappello J, Lodish H F
Mol Cell Biol. 1984 Nov;4(11):2332-40. doi: 10.1128/mcb.4.11.2332-2340.1984.
DIRS-1 is a Dictyostelium discoideum transposable element that contains heat shock promoter sequences in the inverted terminal repeats. We showed that transcription of a 4.5-kilobase polyadenylated RNA initiates at a discrete site within the left-terminal repeat of DIRS-1, downstream from heat shock promoter and TATA box sequences. This RNA represents a full-length transcript of DIRS-1. We describe a cDNA clone that contains the 4.1 kilobases of internal sequence of DIRS-1, a cDNA clone that spans the junction between the internal sequences and the right-terminal repeat, and a cDNA clone that appears to have been transcribed from a rearranged genomic copy of DIRS-1. A second DIRS-1 RNA, named E1, is transcribed on the opposite strand of DIRS-1 from the 4.5-kilobase RNA and is under control of the heat shock promoter in the right-terminal repeat. E1 transcription initiates at multiple positions both within and downstream from the right-terminal repeat. The same transcriptional initiation sites are used during normal development and during heat shock, suggesting that in all cases DIRS-1 transcription is regulated by the heat shock promoters contained within the two terminal repeats.
DIRS-1是一种盘基网柄菌转座元件，其反向末端重复序列中含有热休克启动子序列。我们发现，一个4.5千碱基的多聚腺苷酸化RNA的转录起始于DIRS-1左末端重复序列内的一个离散位点，位于热休克启动子和TATA框序列的下游。这种RNA代表DIRS-1的全长转录本。我们描述了一个包含DIRS-1内部序列4.1千碱基的cDNA克隆、一个跨越内部序列与右末端重复序列交界处的cDNA克隆，以及一个似乎是从DIRS-1重排基因组拷贝转录而来的cDNA克隆。第二种DIRS-1 RNA，名为E1，从4.5千碱基RNA的相反链上转录而来，受右末端重复序列中的热休克启动子控制。E1转录在右末端重复序列内及其下游的多个位置起始。在正常发育和热休克期间使用相同的转录起始位点，这表明在所有情况下，DIRS-1转录都受两个末端重复序列中所含热休克启动子的调控。
