Ratnasabapathy R, Sheldon M, Johal L, Hernandez N
Cold Spring Harbor Laboratory, New York 11724.
Genes Dev. 1990 Dec;4(12A):2061-74. doi: 10.1101/gad.4.12a.2061.
We describe an unusual element that activates the synthesis of short transcripts from a wide variety of mRNA and small nuclear RNA (snRNA) promoters, including the U6 RNA polymerase III promoter. This inducer of short transcripts (IST) is located between positions -5 and +82 relative to the cap site in the HIV-1 LTR. In the presence of IST, the total transcriptional activity of the different promoters is greatly increased, but the resulting additional RNA molecules are short, ending around position +60. IST is not the RNA target (TAR) for Tat trans-activation; however, because it relies entirely on cellular factors for activity, IST may serve to provide abundant RNA targets for Tat trans-activation without a requirement for full-length viral mRNA expression.
我们描述了一种不寻常的元件，它可激活多种信使核糖核酸（mRNA）和小核核糖核酸（snRNA）启动子（包括U6 RNA聚合酶III启动子）的短转录本合成。这种短转录本诱导剂（IST）位于相对于HIV-1长末端重复序列（LTR）中帽位点的-5至+82位之间。在IST存在的情况下，不同启动子的总转录活性大大增加，但产生的额外RNA分子较短，在+60位左右终止。IST不是Tat反式激活的RNA靶标（TAR）；然而，由于它完全依赖细胞因子发挥活性，IST可能有助于为Tat反式激活提供丰富的RNA靶标，而无需全长病毒mRNA表达。
