NAD capping of RNA: mechanism and functions

Living organisms employ complex mechanisms for precise control of gene expression. Modification of RNA molecules is one of these mechanisms, and a major type of RNA modification is RNA capping. Eukaryotic mRNAs typically contain the methylguanosine (m7G) cap on the 5' end which is critical for gene expression, whereas prokaryotic RNAs were previously thought to be uncapped. Recently, some RNAs in both prokaryotic and eukaryotic cells have been found to contain NAD as a 5' cap, indicating a previously unknown mechanism in controlling gene expression through non-canonical RNA capping. The mechanism that controls NAD capping and the molecular and biological functions of NAD-capped RNAs (NAD-RNAs) remain elusive.

We have developed multiple methods for identification and characterization of NAD-capped RNAs (NAD-RNAs) in various organisms. Our findings indicate that NAD-RNAs likely have regulatory functions. In this study, we will use E. coli and Arabidopsis as the model organisms to understand the molecular mechanisms that control NAD capping. Molecular and genetic approaches will be employed to reveal the molecular mode of action of some NAD-RNAs, particularly in transcriptional control. This project will be carried out through multi-disciplinary collaboration with investigators who have complementary knowledge and skills in molecular biology, RNA biology, analytical chemistry, structural biology, biochemistry, and cell biology.

Funding

Research Grant Council - Collaborative Research Fund