NAD-capped RNAs in Arabidopsis may link gene regulation and energy metabolism

RNA modifications play a critical role in controlling gene expression. In eukaryotic cells, one of the best-known RNA modifications is addition of the methylated guanosine (m7G) cap to the 5′ end of an mRNA molecule. In recent years, some RNA molecules in prokaryotes and eukaryotes have been found to contain a non-canonical cap, such as the NAD cap, indicating additional complexity in gene regulation through RNA capping. However, the role of the NAD cap remains elusive. NAD is a vital molecule in energy metabolism, and it is conceivable that NAD capping is influenced by cellular energy status and might in turn mediate gene expression to rewire energy metabolism.

We have developed multiple methods to identify and characterize NAD-capped RNAs (NAD-RNAs) in Arabidopsis and other organisms. Using our newly developed methods, we have found that NAD-capped RNAs are widespread in bacteria; while in eukaryotes, NAD-RNAs are produced mainly from genes involved in energy metabolism. Our recent findings suggest that NAD-RNAs most likely act as regulatory RNAs. In this proposal, we will use methods developed in our lab to understand the effect of energy status on production of NAD-RNAs in Arabidopsis and to define a possible role of NAD capping in regulating expression of genes involved in energy metabolism. Our study will address a new layer of regulation in energy metabolism and advance the new field of NAD-RNA biology.