Functional RNA polymerase II promoters in solitary retroviral long terminal repeats (LTR-IS elements).

摘要

LTR-IS elements are middle repetitive sequences in the mouse genome with structural features of solitary retroviral LTRs. In order to get some insight in the possible functional role of these sequences the promotor activity of two LTR-IS representatives differing by 105 bp in their U3 region was investigated. Gene fusions between LTR-IS sequences and the bacterial gene coding for chloramphenicol acetyl transferase (CAT) were transfected into mouse 3T6 cells and the expression of CAT was measured. It is shown that the LTR-IS sequences represent weak RNA polymerase II promoters which require enhancement by cis-or trans-activating factors.