{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T09:18:53Z","timestamp":1787822333781,"version":"build-2784847793"},"reference-count":34,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T00:00:00Z","timestamp":1787788800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100018818","name":"Hungarian National Research, Development and Innovation Office","doi-asserted-by":"publisher","award":["NKFI-K 142961"],"award-info":[{"award-number":["NKFI-K 142961"]}],"id":[{"id":"10.13039\/501100018818","id-type":"DOI","asserted-by":"publisher"}]},{"award":["NKFI-K 142961"],"award-info":[{"award-number":["NKFI-K 142961"]}],"id":[{"id":"https:\/\/ror.org\/03g2am276","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100015763","name":"University of Szeged Open Access Fund","doi-asserted-by":"publisher","award":["8804"],"award-info":[{"award-number":["8804"]}],"id":[{"id":"10.13039\/501100015763","id-type":"DOI","asserted-by":"publisher"}]},{"award":["8804"],"award-info":[{"award-number":["8804"]}],"id":[{"id":"https:\/\/ror.org\/01pnej532","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomolecules"],"abstract":"<jats:p>Assemblysomes are ribosome-nascent chain condensates that regulate co-translational processes through liquid\u2013liquid phase separation, yet the sequence determinants underlying their formation remain incompletely understood. Previous studies identified the DNA helicase Sgs1 as an assemblysome-associated protein; however, whether its N-terminal region possesses intrinsic phase separation propensity has not been experimentally examined. Here, we investigated the first 135 amino acids of Sgs1 using a light-inducible optoDroplet assay. A mCherry\u2013Cry2\u2013Sgs11\u2013135 fusion construct was compared with the established positive control FUS\u2013mCherry\u2013Cry2 and the negative control mCherry\u2013Cry2 in live HEK293T cells. Following blue-light activation, Sgs11\u2013135 reproducibly formed reversible condensates, indicating intrinsic phase separation propensity. Quantitative image analysis revealed light-dependent increases in condensate number, average condensate area, and integrated condensate fluorescence intensity. Compared with FUS, Sgs11\u2013135 formed slightly fewer and smaller condensates but displayed reproducible light-dependent condensate formation. These findings indicate that the Sgs1 N-terminal region exhibits intrinsic phase separation propensity in a validated optogenetic assay. Although this proof-of-principle study does not establish the molecular mechanism of assemblysome formation, the results are consistent with the hypothesis that the Sgs1 N-terminus may contribute to the multivalent interactions underlying assemblysome organization.<\/jats:p>","DOI":"10.3390\/biom16091240","type":"journal-article","created":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T08:02:27Z","timestamp":1787817747000},"page":"1240","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Optogenetic Evidence for the Intrinsic Phase Separation Propensity of the Sgs1 N-Terminal Region: Implications for Assemblysome Formation"],"prefix":"10.3390","volume":"16","author":[{"given":"Bence Gy\u00f6rgy","family":"Gomb\u00e1s","sequence":"first","affiliation":[{"name":"Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, 6726 Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0477-6127","authenticated-orcid":false,"given":"Erika","family":"G\u00e1bor","sequence":"additional","affiliation":[{"name":"Drosophila Blood Cell Differentiation Group, Institute of Genetics, HUN-REN Biological Research Centre, 6726 Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Viktor","family":"Honti","sequence":"additional","affiliation":[{"name":"Drosophila Blood Cell Differentiation Group, Institute of Genetics, HUN-REN Biological Research Centre, 6726 Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Orsolya","family":"N\u00e9meth-Szatm\u00e1ri","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, 6726 Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9697-4472","authenticated-orcid":false,"given":"Ferenc","family":"Jankovics","sequence":"additional","affiliation":[{"name":"Laboratory of Drosophila Germ Cell Differentiation, Institute of Genetics, HUN-REN Biological Research Centre, 6726 Szeged, Hungary"},{"name":"Department of Medical Biology, Albert Szent-Gy\u00f6rgyi Medical Centre, University of Szeged, 6720 Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8563-9713","authenticated-orcid":false,"given":"Zolt\u00e1n","family":"Vill\u00e1nyi","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, 6726 Szeged, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"e70009","DOI":"10.1002\/wrna.70009","article-title":"Role of assemblysomes in cellular stress responses","volume":"16","year":"2025","journal-title":"WIREs RNA"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"196","DOI":"10.1038\/s41580-020-00326-6","article-title":"Biomolecular Condensates at the Nexus of Cellular Stress, Protein Aggregation Disease and Ageing","volume":"22","author":"Alberti","year":"2021","journal-title":"Nat. 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