Sequence-specific targeting of RNA.

Post-transcriptional modifications play an important role in several processes, including translation, splicing, and RNA degradation in eukaryotic cells. To investigate the function of specific modifications it is of high interest to develop tools for sequence-specific RNA-targeting. This work focuses on two abundant modifications of eukaryotic mRNA, namely methylation of the guanine-N7 position of the 5'-cap and internal N-methyladenosine (mA).

Computational design and experimental characterization of a photo-controlled mRNA-cap guanine-N7 methyltransferase.

The spatial and temporal control of gene expression at the post-transcriptional level is essential in eukaryotic cells and developing multicellular organisms. In recent years optochemical and optogenetic tools have enabled the manipulation and investigation of many steps in the involved processes. However, examples for light-mediated control of eukaryotic mRNA processing and the responsible enzymes are still rare.

Light-control of cap methylation and mRNA translation genetic code expansion of Ecm1.

Gene expression is tightly regulated in all domains of life, with post-transcriptional regulation being more pronounced in higher eukaryotes. Optochemical and optogenetic approaches enable the actuation of many underlying processes by light, which is an excellent tool to exert spatio-temporal control. However, light-mediated control of eukaryotic mRNA processing and the respective enzymes has not been reported.

Quantification of mRNA cap-modifications by means of LC-QqQ-MS.

Enzymatic modification of the 5'-cap is a versatile approach to modulate the properties of mRNAs. Transfer of methyl groups from S-adenosyl-l-methionine (AdoMet) or functional moieties from non-natural analogs by methyltransferases (MTases) allows for site-specific modifications at the cap. These modifications have been used to tune translation or control it in a temporal manner and even influence immunogenicity of mRNA.

Practical Synthesis of Cap-4 RNA.

Eukaryotic mRNAs possess 5' caps that are determinants for their function. A structural characteristic of 5' caps is methylation, with this feature already present in early eukaryotes such as Trypanosoma. While the common cap-0 (m GpppN) shows a rather simple methylation pattern, the Trypanosoma cap-4 displays seven distinguished additional methylations within the first four nucleotides.

A One-Pot Cascade Reaction Combining an Encapsulated Decarboxylase with a Metathesis Catalyst for the Synthesis of Bio-Based Antioxidants.

The combination of enzymes with traditional chemical catalysts unifies the high selectivity of the former with the versatility of the latter. A major challenge of this approach is the difference in the optimal reaction conditions for each catalyst type. In this work, we combined a cofactor-free decarboxylase with a ruthenium metathesis catalyst to produce high-value antioxidants from bio-based precursors.