To the Frontier of RNA Glycosylation: Novel Insights from Metabolic Labelling

The recent discovery of glycosylated RNA (glycoRNA) has redefined our comprehension of the glyco-conjugate universe, uncovering an unprecedented link between glycans and RNA. The pioneering exploration of this novel biopolymer was driven by the metabolic carbohydrate reporter, per-O-acetylated N-azidomannosamine (Ac4ManNAz), that emphasises the unknown potential of the field of glycobiology and RNA modification. However, the nascent field raises numerous questions concerning the molecule's authenticity, structure, and intricate biological roles, warranting further investigation. This thesis systematically expands upon this initial finding by harnessing additional metabolic probes, including per-O-acetylated N-azidoacetylglucosamine (Ac4GlcNAz), N-azidoacetylgalactosamine (Ac4GalNAz), and 6-azidofucose (Ac4FucAz). Our successful integration of Ac4GlcNAz and Ac4GalNaz into intracellular RNA has added another dimension to our knowledge of RNA glycosylation. We further developed an effective pulldown and release method, which ensures a high-confidence detection and analysis of our azido sugar-RNA. We uncover new dimensions of RNA glycosylation, including a peculiar lack of overlap between RNA and sugar probe signal, as well an unusual resilience of sugar-RNA bonds to enzymatic cleavage. This led us to unravel a novel non-enzymatic sugar-RNA linkages, adding a new layer of intrigue to the glycoRNA narrative. Through meticulous sequencing and a novel annotation workflow, we have used high-confidence transcript profiling to identify distinct sets corresponding to each sugar probe, thereby highlighting the diversity of these sugar-RNA species. Collectively, this thesis provides a robust and critical understanding of the largely unexplored field of glycoRNA. We present findings that reinforce the concept of RNA glycosylation, while also revealing major uncertainties surrounding the nature and authenticity of glycoRNA. This work thus serves as a foundation for future research in this nascent field, underscoring the importance of decisively unravelling the linkage structure of glycoRNA and maintaining rigorous scrutiny in the pursuit of early-stage scientific investigations of this field.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2023

Author dc:creator

• Hazemi, Madoka Eurika

Advisor dc:contributor.advisor

• Bernardes, Gonçalo

• GlycoRNA
• Metabolic labelling
• RNA modification

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/202665b8-329b-4551-b15f-4d16e26020ac/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.105800

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/363944