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Project Abstract  T-Rex 

The project aims to realize a device with standard biological parts for the post-transcriptional control of gene expression, regardless of the gene sequence to be silenced. We designed the T-REX device, composed of two non-coding DNA sequences: the TRANS-repressor and the CIS-repressing parts. TRANS-repressor acts as a silencer of CIS-repressing RNA target. This target includes a region complementary to the TRANS-repressor sequence antisense, ends with RBS, and is assembled upstream of the coding sequence to be silenced. Upon binding of TRANS-repressor and CIS-repressing RNAs, the access to RBS by ribosomes is hampered, silencing translation. Accordingly, the amount of TRANS-repressor controls the translation rate of the regulated gene. The TRANS-repressor sequence was determined by a computational analysis performed to minimize the interference with the genomic mRNAs and to maximize the base-pairing interaction to the CIS-repressing RNA. The T-REX device is proposed as a universal and fast switch in synthetic gene circuits.