Translational Regulation of PTEN/MMAC1 Expression in Prostate Cancer

摘要

In this project, we proposed to use a dicistronic expression system to determine whether the long 5'-UTR sequence of PTEN contains internal ribosome entry site (IRES) which can mediate cap-independent translation. We have accomplished the proposed work as planed. However, we found that the long 5'-UTR sequence of PTEN does not have the predicted IRES activity but rather contains a strong promoter. We have mapped this promoter and it is likely responsible for constitutive production of the PTEN mRNAs with shorter 5'-UTRs in prostate cancer cells which would be compatible for cap-dependent translation initiation. We have also created a promoterless dicistronic vector and validated its use as a more stringent assay for testing cellular IRES activities.