{"data":{"event":{"id":"83509be5-2f5b-43bc-8e9a-95b463dbff8e","slug":"phase-separation-potential-of-marsupial-rsx-rna-reveals-convergent-evolu-e199c22caf","title":"\n\nPhase Separation Potential of Marsupial RSX RNA Reveals Convergent Evolution of X-Chromosome Inactivation Mechanisms \n\n","short_summary":"Background: X-chromosome inactivation (XCI) evolved independently in eutherian and marsupial mammals, where it is orchestrated by the unrelated long non-coding RNAs Xist and RSX, respectively. Xist organizes a repressive nuclear compartment through multivalent RNA-protein interactions, but whether RSX exploits similar biophysical principles remains unknown. A recent paper has identified bona fide RSX interacting proteins. Results: We integrated proteome-scale RNA-protein interaction prediction, experimental validation, phase-separation propensity analysis, functional annotation and comparative","full_description":"Background: X-chromosome inactivation (XCI) evolved independently in eutherian and marsupial mammals, where it is orchestrated by the unrelated long non-coding RNAs Xist and RSX, respectively. Xist organizes a repressive nuclear compartment through multivalent RNA-protein interactions, but whether RSX exploits similar biophysical principles remains unknown. A recent paper has identified bona fide RSX interacting proteins. Results: We integrated proteome-scale RNA-protein interaction prediction, experimental validation, phase-separation propensity analysis, functional annotation and comparative RNA-structure modelling to characterize the RSX interaction landscape. Using catRAPID, we ranked 1,168 RNA-binding proteins from the native Monodelphis domestica proteome. Predictions were significantly enriched for experimentally identified RSX interactors, with 4.85-fold enrichment among the top 50 candidates (P approximately 1.6 x 10-5), increasing to approximately eightfold for proteins shared by the experimental RSX and Xist interactomes (P approximately 2 x 10-6). Among 30 high-confidence RSX interactors, 13 were experimentally supported, 17 were previously unrecognized candidates and 17 exhibited high phase-separation propensity. The network was enriched in ribonucleoprotein granules and nuclear bodies and converged on m6A regulators and SR-family splicing factors. Comparative modelling detected no conserved secondary or tertiary architecture between RSX and Xist. Conclusions: RSX and Xist appear to have converged not through RNA sequence or global structure, but through recruitment of related, condensation-prone protein networks. These findings identify interaction-network and biophysical convergence as a potential principle of lncRNA-mediated chromosome regulation and provide testable candidates for determining whether RSX establishes a condensate-like compartment on the marsupial inactive X.","ledger_type":"benefit","primary_domain_id":"8f1af1b9-7302-4b51-aae9-fdfac04d158a","event_status":"provisional","event_date":"2026-09-24T00:00:00.000Z","discovery_date":"2026-09-24T00:00:00.000Z","first_published_date":"2026-09-24T00:00:00.000Z","last_reviewed_date":"2026-09-24T00:00:00.000Z","geographic_scope":"International","affected_population":null,"base_impact_tier":1,"base_score":"1.00","attribution_multiplier":"0.1000","evidence_multiplier":"0.1000","realization_multiplier":"0.2000","durability_multiplier":"0.5000","current_event_score":"0.001000","confidence_level":"low","score_explanation":"Auto-published from news ingest as a provisional placeholder. Score is conservative until a named release is identified and the record is rescored.","methodology_version_id":"8745541b-0f8e-4d5a-9b47-5291d3813a8d","original_methodology_version_id":"8745541b-0f8e-4d5a-9b47-5291d3813a8d","published_at":"2026-09-24T13:00:56.143Z","created_at":"2026-09-24T13:00:56.143Z","updated_at":"2026-09-24T13:00:56.143Z","flags":[],"domain_name":"Biology","domain_slug":"biology","methodology_version":"0.2"},"contributions":[{"id":"a9f21dfa-99bb-4cc8-b59c-bf3159fefe5c","event_id":"83509be5-2f5b-43bc-8e9a-95b463dbff8e","model_id":"535014f7-c941-4d39-aa9b-8f9c1d3d07b7","role_description":"Unspecified system mentioned or implied by a news item. Remap to a named release when identified.","attribution_multiplier":"0.1000","credit_share":"1.0000","contribution_score":"0.001000","attribution_rationale":"News ingest does not infer a named model from the publisher alone. Attribution stays unspecified until a release is identified.","attribution_confidence":"medium","first_used_date":"2026-09-24T00:00:00.000Z","model_version_if_known":null,"review_status":"approved","created_at":"2026-09-24T13:00:56.153Z","model_slug":"unspecified-ai-system","model_name":"Unspecified AI system","identity_class":"unknown","is_internal":false,"family_name":"Unspecified","family_slug":"unknown-unspecified","organization_name":"Unknown","organization_slug":"unknown"}],"sources":[{"id":"e2afa9e2-db98-411a-aeb9-95398dc85f05","event_id":"83509be5-2f5b-43bc-8e9a-95b463dbff8e","url":"\nhttps://www.biorxiv.org/content/10.64898/2026.09.18.752704v1?rss=1\n","canonical_url":"\nhttps://www.biorxiv.org/content/10.64898/2026.09.18.752704v1?rss=1\n","source_type":"preprint","publisher":"bioRxiv","author":null,"publication_date":"2026-09-24T00:00:00.000Z","retrieved_at":"2026-09-24T13:00:56.160Z","title":"\n\nPhase Separation Potential of Marsupial RSX RNA Reveals Convergent Evolution of X-Chromosome Inactivation Mechanisms \n\n","excerpt":"Background: X-chromosome inactivation (XCI) evolved independently in eutherian and marsupial mammals, where it is orchestrated by the unrelated long non-coding RNAs Xist and RSX, respectively. Xist organizes a repressive nuclear compartment through multivalent RNA-protein interactions, but whether RSX exploits similar biophysical principles remains unknown. A recent paper has identified bona fide RSX interacting proteins. Results: We integrated proteome-scale RNA-protein interaction prediction, ","content_hash":null,"source_reliability_class":"medium","is_primary_source":true,"is_independent":true,"is_peer_reviewed":false,"archived_url":null,"created_at":"2026-09-24T13:00:56.160Z"}],"claims":[{"id":"04300b56-6a3d-43ab-8f30-0d3d0a6f7698","event_id":"83509be5-2f5b-43bc-8e9a-95b463dbff8e","claim_text":"\n\nPhase Separation Potential of Marsupial RSX RNA Reveals Convergent Evolution of X-Chromosome Inactivation Mechanisms \n\n","claim_type":"outcome","claim_status":"supported","confidence_score":null,"created_at":"2026-09-24T13:00:56.169Z","updated_at":"2026-09-24T13:00:56.169Z"}],"revisions":[{"id":"b32bdd45-17a6-4335-b559-0620e8229177","event_id":"83509be5-2f5b-43bc-8e9a-95b463dbff8e","model_id":null,"previous_score":"0.000000","new_score":"0.001000","previous_factors":{},"new_factors":{"tier":1,"evidence":0.1,"base_score":1,"durability":0.5,"attribution":0.1,"realization":0.2},"change_reason":"Auto-published from news ingest.","trigger_type":"news_ingest","trigger_source_ids":null,"reviewer_id":null,"review_status":"published","created_at":"2026-09-24T13:00:56.176Z"}],"secondary":[]},"methodology_version":"0.1"}