Interferon signalling is one of the most important mechanisms shaping innate immune responses and needs to be tightly regulated to successfully fight infections and regulate immune responses while avoiding toxicity. Type-1 interferons (IFN), induce changes in cells on many different levels, such as transcriptional, translational and metabolic. In this study, many of these changes have been characterized on a global level in murine and human macrophages using multi-omics strategies.
We conducted time-course experiments treating murine bone marrow-derived macrophages or human blood monocyte-derived macrophages with IFN-beta. While confirming changes described in previous studies, we also found a large number of transcripts expressing a shortened 3’ untranslated region (3’-UTR), a region heavily targeted by miRNAs and harbouring binding sites for many RNA binding proteins. Subsequently, this project has been focusing on 3’-UTR dynamics, a field that is only starting to be explored. The regulation and function of this process in an interferon context remain unknown.
Recent publications have described a role of 3’-UTRs in mediating differential protein complex formation, which can affect localization and function. This unique regulatory function of 3’-UTR length will be addressed for two candidate proteins. 3’-UTR-dependent protein-protein interactions will be identified by mass spectrometry using overexpression constructs.
We also aim to identify components involved in mediating the shortening of 3’-UTRs in response to IFN-beta treatment using a CRISPR/Cas9-based screening approach to shed light on how this novel signalling pathway is initiated.
This study describes a new aspect of interferon signalling and a novel layer of regulation through non-ISGs. It will show how differential expression of distinct 3’-UTR transcript isoforms shapes macrophage innate immune responses.