SummaryNuclear RNA metabolism is influenced by protein complexes connecting to both RNA-productive and -destructive pathways. The ZC3H18 protein binds the cap-binding complex (CBC), universally present on capped RNAs, while also associating with the nuclear exosome targeting (NEXT) complex, linking to RNA decay. To dissect ZC3H18 function, we conducted interaction screening and mutagenesis of the protein, which revealed a phosphorylation-dependent isoform. Surprisingly, the modified region of ZC3H18 associates with core histone proteins. Further examination of ZC3H18 function, by genome-wide analyses, demonstrated its impact on transcription of a subset of protein-coding genes. This activity requires the CBC-interacting domain of the protein, with some genes being also dependent on the NEXT- and/or histone-interacting domains. Our data shed light on the domain requirements of a protein positioned centrally in nuclear RNA metabolism, and they suggest that post-translational modification may modulate its function.

We have developed an approach termed PUB-NChIP (proximity utilizing biotinylation with native ChIP) to purify and study the protein composition of chromatin in proximity to a nuclear protein of interest. It is based on coexpression of (1) a protein of interest, fused with the bacterial biotin ligase BirA, together with (2) a histone fused to a biotin acceptor peptide (BAP), which is specifically biotinylated by BirA-fusion in the proximity of the protein of interest. Using the RAD18 protein as a model, we demonstrate that the RAD18-proximal chromatin is enriched in some H4 acetylated species. Moreover, the RAD18-proximal chromatin containing a replacement histone H2AZ has a different pattern of H4 acetylation. Finally, biotin pulse-chase experiments show that the H4 acetylation pattern starts to resemble the acetylation pattern of total H4 after the proximity of chromatin to RAD18 has been lost.

Abstract ARS2 is a conserved protein centrally involved in both nuclear RNA productive and destructive processes. To map features of ARS2 promoting RNA decay, we utilized two different RNA reporters, one of which depends on direct ARS2 tethering for its degradation. In both cases, ARS2 triggers a degradation phenotype aided by its interaction with the poly(A) tail exosome targeting (PAXT) connection. Interestingly, C-terminal amino acids of ARS2, responsible for binding the RNA 5′cap binding complex (CBC), become dispensable when ARS2 is directly tethered to the reporter RNA. In contrast, the Zinc-finger (ZnF) domain of ARS2 is essential for the decay of both reporters and consistently co-immunoprecipitation analyses reveal a necessity of this domain for the interaction of ARS2 with the PAXT-associated RNA helicase MTR4. Taken together, our results map the domains of ARS2 underlying two essential properties of the protein: its RNP targeting ability and its capacity to recruit the RNA decay machinery.

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The untranslated regions (UTRs) of viral genomes contain av ariety of conserved yet dynamic structures crucial for viral replication, providing drug targets for the development of broad spectrum anti-virals.W ecombine in vitro RNA analysis with molecular dynamics simulations to build the first 3D models of the structure and dynamics of key regions of the 5' UTR of the SARS-CoV-2 genome.F urthermore,w e determine the binding of metallo-supramolecular helicates (cylinders) to this RNAs tructure.T hese nano-sizea gents are uniquely able to thread through RNAjunctions and we identify their binding to a3 -base bulge and the central cross 4-way junction located in stem loop 5. Finally,w es how these RNAbinding cylinders suppress SARS-CoV-2 replication, highlighting their potential as novel anti-viral agents.

Mutations and aberrant gene expression during cellular differentiation lead to neurodevelopmental disorders, such as Prader-Willi syndrome (PWS) which results from the deletion of an imprinted locus on paternally inherited chromosome 15. We analysed chromatin-associated RNA in human induced pluripotent cells (iPSCs) upon depletion of hybrid small nucleolar long non-coding RNAs (sno-lncRNAs) and 5’ snoRNA capped and polyadenylated long non-coding RNAs (SPA-lncRNAs) transcribed from the locus deleted in PWS. We found that rapid ablation of these lncRNAs affects transcription of specific gene classes. Downregulated genes contribute to neurodevelopment and neuronal maintenance while genes that are upregulated are predominantly involved in the negative regulation of cellular metabolism and apoptotic processes. Our data reveal the importance of SPA-lncRNAs and sno-lncRNAs in controlling gene expression in iPSCs and provide a platform for synthetic experimental approaches in PWS studies. We conclude that ncRNAs transcribed from the PWS locus are critical regulators of a transcriptional signature, which is important for neuronal differentiation and development.

The untranslated regions (UTRs) of viral genomes contain a variety of conserved yet dynamic structures crucial for viral replication, providing drug targets for the development of broad spectrum anti‐virals. We combine in vitro RNA analysis with molecular dynamics simulations to build the first 3D models of the structure and dynamics of key regions of the 5′ UTR of the SARS‐CoV‐2 genome. Furthermore, we determine the binding of metallo‐supramolecular helicates (cylinders) to this RNA structure. These nano‐size agents are uniquely able to thread through RNA junctions and we identify their binding to a 3‐base bulge and the central cross 4‐way junction located in stem loop 5. Finally, we show these RNA‐binding cylinders suppress SARS‐CoV‐2 replication, highlighting their potential as novel anti‐viral agents.

The untranslated regions (UTRs) of viral genomes contain a variety of conserved yet dynamic structures crucial for viral replication, providing drug targets for the development of broad spectrum anti-virals. We combine in vitro RNA analysis with Molecular Dynamics simulations to build the first 3D models of the structure and dynamics of key regions of the 5-prime UTR of the SARS-CoV-2 genome. Furthermore, we determine the binding of metallo-supramolecular helicates (cylinders) to this RNA structure. These nano-size agents are uniquely able to thread through RNA junctions and we identify their binding to a 3-base bulge and the central cross 4-way junction located in the stem loop 5. Finally, we show these RNA-binding cylinders suppress SARS-CoV-2 replication, highlighting their potential as novel anti-viral agents.