{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:32:13Z","timestamp":1760059933585,"version":"build-2065373602"},"reference-count":57,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,7,26]],"date-time":"2025-07-26T00:00:00Z","timestamp":1753488000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000268","name":"BBSRC","doi-asserted-by":"publisher","award":["BB\/M020797\/1","BB\/P000215\/1","BB\/V014218\/1"],"award-info":[{"award-number":["BB\/M020797\/1","BB\/P000215\/1","BB\/V014218\/1"]}],"id":[{"id":"10.13039\/501100000268","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomolecules"],"abstract":"<jats:p>We identified Murashka, a RING finger protein, in an oogenesis screen as a regulator of Drosophila ovary germline stem cell niche development. Mutant alleles of murashka exhibited an enlarged niche phenotype reminiscent of increased Notch signalling and displayed genetic interactions with Notch alleles, and with polychaetoid, a regulator of Notch during niche development. These interactions uncovered both positive and negative impacts on Notch in different genetic backgrounds. In S2 cells, Murashka formed a complex with Notch and colocalised with Notch in the secretory pathway. Murashka expression in S2 cells down-regulated Notch signalling levels but could result in increased fold induction due to the proportionally greater decrease in basal ligand-independent activity. In vivo Murashka expression had different outcomes on different Notch target genes. We observed a decrease in the expression of vestigial along the anterior\/posterior boundary of the wing imaginal disc, but not of wingless at the dorsal\/ventral boundary. Instead, weak ectopic wingless was observed, which was synergistically increased by the coexpression of Deltex, a positive regulator of ligand-independent signalling. Our results identify a novel developmental role for murashka, a gene previously only associated with a function in long-term memory, and indicate a regulatory role for Murashka through a physical interaction with Notch that has context-dependent outcomes. Murashka adds to a growing number of ubiquitin ligase regulators which interact with Notch at different locations within its secretory and endocytic trafficking pathways.<\/jats:p>","DOI":"10.3390\/biom15081082","type":"journal-article","created":{"date-parts":[[2025,7,28]],"date-time":"2025-07-28T07:57:24Z","timestamp":1753689444000},"page":"1082","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The Memory Gene, Murashka, Is a Regulator of Notch Signalling and Controls the Size of the Drosophila Germline Stem Cell Niche"],"prefix":"10.3390","volume":"15","author":[{"given":"Thifeen","family":"Deen","sequence":"first","affiliation":[{"name":"School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Oxford Rd., Manchester M13 9PT, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-9426-8651","authenticated-orcid":false,"given":"Hideyuki","family":"Shimizu","sequence":"additional","affiliation":[{"name":"School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Oxford Rd., Manchester M13 9PT, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2203-3551","authenticated-orcid":false,"given":"Marian B.","family":"Wilkin","sequence":"additional","affiliation":[{"name":"School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Oxford Rd., Manchester M13 9PT, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Martin","family":"Baron","sequence":"additional","affiliation":[{"name":"School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Oxford Rd., Manchester M13 9PT, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3593","DOI":"10.1242\/dev.063610","article-title":"Notch signaling: Simplicity in design, versatility in function","volume":"138","author":"Andersson","year":"2011","journal-title":"Development"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1016\/S1084-9521(02)00179-9","article-title":"An overview of the Notch signalling pathway","volume":"14","author":"Baron","year":"2003","journal-title":"Semin. Cell Dev. Biol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1111\/boc.202100009","article-title":"The role of ligand endocytosis in notch signalling","volume":"113","author":"Seib","year":"2021","journal-title":"Biol. Cell"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1016\/S0960-9822(00)00044-0","article-title":"A model Notch response element detects Suppressor of Hairless-dependent molecular switch","volume":"11","author":"Furriols","year":"2001","journal-title":"Curr. Biol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/j.ceb.2017.12.008","article-title":"Notch after cleavage","volume":"51","author":"Bray","year":"2018","journal-title":"Curr. Opin. Cell Biol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2237","DOI":"10.1016\/j.cub.2004.11.030","article-title":"Regulation of Notch endosomal sorting and signaling by Drosophila Nedd4 family proteins","volume":"14","author":"Wilkin","year":"2004","journal-title":"Curr. Biol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"762","DOI":"10.1016\/j.devcel.2008.09.002","article-title":"Drosophila HOPS and AP-3 complex genes are required for a Deltex-regulated activation of Notch in the endosomal trafficking pathway","volume":"15","author":"Wilkin","year":"2008","journal-title":"Dev. Cell"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1160","DOI":"10.1016\/j.cell.2014.03.050","article-title":"Compensatory flux changes within an endocytic trafficking network maintain thermal robustness of Notch signaling","volume":"157","author":"Shimizu","year":"2014","journal-title":"Cell"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Shimizu, H., Hosseini-Alghaderi, S., Woodcock, S.A., and Baron, M. (2024). Alternative mechanisms of Notch activation by partitioning into distinct endosomal domains. J. Cell Biol., 223.","DOI":"10.1083\/jcb.202211041"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"35847","DOI":"10.1074\/jbc.M103992200","article-title":"The Notch intracellular domain is ubiquitinated and negatively regulated by the mammalian Sel-10 homolog","volume":"276","author":"Oberg","year":"2001","journal-title":"J. Biol. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"16287","DOI":"10.1073\/pnas.0703508104","article-title":"Kaposi\u2019s sarcoma herpesvirus-encoded latency-associated nuclear antigen stabilizes intracellular activated Notch by targeting the Sel10 protein","volume":"104","author":"Lan","year":"2007","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"5527","DOI":"10.1242\/dev.01448","article-title":"Drosophila deltex mediates suppressor of Hairless-independent and late-endosomal activation of Notch signaling","volume":"131","author":"Hori","year":"2004","journal-title":"Development"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1071","DOI":"10.1242\/dev.003392","article-title":"Notch signaling controls germline stem cell niche formation in the Drosophila ovary","volume":"134","author":"Song","year":"2007","journal-title":"Development"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1117","DOI":"10.1073\/pnas.0809144106","article-title":"Insulin levels control female germline stem cell maintenance via the niche in Drosophila","volume":"106","author":"Hsu","year":"2009","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Bonfini, A., Wilkin, M.B., and Baron, M. (2015). Reversible regulation of stem cell niche size associated with dietary control of Notch signalling. BMC Dev. Biol., 15.","DOI":"10.1186\/s12861-015-0059-8"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1083\/jcb.201007023","article-title":"Su(dx) E3 ubiquitin ligase-dependent and -independent functions of polychaetoid, the Drosophila ZO-1 homologue","volume":"192","author":"Djiane","year":"2011","journal-title":"J. Cell Biol."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Shimizu, H., Wilkin, M.B., Woodcock, S.A., Bonfini, A., Hung, Y., Mazaleyrat, S., and Baron, M. (2017). The Drosophila ZO-1 protein Polychaetoid suppresses Deltex-regulated Notch activity to modulate germline stem cell niche formation. Open Biol., 7.","DOI":"10.1098\/rsob.160322"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1016\/S0092-8674(00)81424-5","article-title":"Decapentaplegic is essential for the maintenance and division of germline stem cells in the Drosophila ovary","volume":"94","author":"Xie","year":"1998","journal-title":"Cell"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"328","DOI":"10.1126\/science.290.5490.328","article-title":"A niche maintaining germ line stem cells in the Drosophila ovary","volume":"290","author":"Xie","year":"2000","journal-title":"Science"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1881","DOI":"10.1242\/dev.01076","article-title":"Germline stem cell number in the Drosophila ovary is regulated by redundant mechanisms that control Dpp signaling","volume":"131","author":"Casanueva","year":"2004","journal-title":"Development"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"238","DOI":"10.1002\/neu.10170","article-title":"Neural substrates of memory: From synapse to system","volume":"54","author":"Dubnau","year":"2003","journal-title":"J. Neurobiol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"286","DOI":"10.1016\/S0960-9822(03)00064-2","article-title":"The staufen\/pumilio pathway is involved in Drosophila long-term memory","volume":"13","author":"Dubnau","year":"2003","journal-title":"Curr. Biol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"895","DOI":"10.1111\/j.1530-0277.2008.00659.x","article-title":"Ethanol sensitivity and tolerance in long-term memory mutants of Drosophila melanogaster","volume":"32","author":"Berger","year":"2008","journal-title":"Alcohol Clin. Exp. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1242\/dev.118.2.401","article-title":"Targeted gene expression as a means of altering cell fates and generating dominant phenotypes","volume":"118","author":"Brand","year":"1993","journal-title":"Development"},{"key":"ref_25","first-page":"585","article-title":"Specificity of bone morphogenetic protein-related factors: Cell fate and gene expression changes in Drosophila embryos induced by decapentaplegic but not 60A","volume":"5","author":"Jackson","year":"1994","journal-title":"Cell Growth Differ."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"535","DOI":"10.1242\/dev.120.3.535","article-title":"The Serrate locus of Drosophila and its role in morphogenesis of the wing imaginal disc: Control of cell proliferation","volume":"120","author":"Speicher","year":"1994","journal-title":"Development"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2579","DOI":"10.1242\/dev.00499","article-title":"Clonal expansion of ovarian germline stem cells during niche formation in Drosophila","volume":"130","author":"Zhu","year":"2003","journal-title":"Development"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1016\/0012-1606(85)90331-8","article-title":"The molecular genetics of the Notch locus in Drosophila melanogaster","volume":"107","author":"Grimwade","year":"1985","journal-title":"Dev. Biol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1016\/0092-8674(87)90123-1","article-title":"Mutations altering the structure of epidermal growth factor-like coding sequences at the Drosophila Notch locus","volume":"51","author":"Kelley","year":"1987","journal-title":"Cell"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"913","DOI":"10.1242\/dev.126.5.913","article-title":"The vestigial gene product provides a molecular context for the interpretation of signals during the development of the wing in Drosophila","volume":"126","author":"Klein","year":"1999","journal-title":"Development"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"4352","DOI":"10.1091\/mbc.e08-03-0246","article-title":"Drosophila Sec16 mediates the biogenesis of tER sites upstream of Sar1 through an arginine-rich motif","volume":"19","author":"Ivan","year":"2008","journal-title":"Mol. Biol. Cell"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"545","DOI":"10.1242\/dev.120.3.545","article-title":"A Drosophila homologue of membrane-skeleton protein 4.1 is associated with septate junctions and is encoded by the coracle gene","volume":"120","author":"Fehon","year":"1994","journal-title":"Development"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1007\/s004180050138","article-title":"A- and B-type lamins are differentially expressed in normal human tissues","volume":"107","author":"Broers","year":"1997","journal-title":"Histochem. Cell Biol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1006\/dbio.1997.8669","article-title":"Spectrosomes and fusomes anchor mitotic spindles during asymmetric germ cell divisions and facilitate the formation of a polarized microtubule array for oocyte specification in Drosophila","volume":"189","author":"Deng","year":"1997","journal-title":"Dev. Biol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"745","DOI":"10.1093\/genetics\/117.4.745","article-title":"Somatic effects of P element activity in Drosophila melanogaster: Pupal lethality","volume":"117","author":"Engels","year":"1987","journal-title":"Genetics"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1353","DOI":"10.1242\/dev.01026","article-title":"Bmp signals from niche cells directly repress transcription of a differentiation-promoting gene, bag of marbles, in germline stem cells in the Drosophila ovary","volume":"131","author":"Song","year":"2004","journal-title":"Development"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2412","DOI":"10.1016\/j.cell.2021.03.035","article-title":"ER-to-Golgi protein delivery through an interwoven, tubular network extending from ER","volume":"184","author":"Weigel","year":"2021","journal-title":"Cell"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"684","DOI":"10.1016\/j.gde.2011.07.008","article-title":"Restricting self-renewal signals within the stem cell niche: Multiple levels of control","volume":"21","author":"Chen","year":"2011","journal-title":"Curr. Opin. Genet. Dev."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Wilkin, M.B., Whiteford, R., Akbar, T., Hosseini-Alghaderi, S., Revici, R., Carbery, A.M., and Baron, M. (2024). The First Defined Null Allele of the Notch Regulator, a Suppressor of Deltex: Uncovering Its Novel Roles in Drosophila melanogaster Oogenesis. Biomolecules, 14.","DOI":"10.3390\/biom14050522"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Tseng, C.Y., Kao, S.H., Wan, C.L., Cho, Y., Tung, S.Y., and Hsu, H.J. (2014). Notch signaling mediates the age-associated decrease in adhesion of germline stem cells to the niche. PLoS Genet., 10.","DOI":"10.1371\/journal.pgen.1004888"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1038\/ncb743","article-title":"A transmembrane ubiquitin ligase required to sort membrane proteins into multivesicular bodies","volume":"4","author":"Reggiori","year":"2002","journal-title":"Nat. Cell Biol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"3971","DOI":"10.1242\/jcs.185702","article-title":"Bidirectional traffic between the Golgi and the endosomes\u2014machineries and regulation","volume":"129","author":"Progida","year":"2016","journal-title":"J. Cell Sci."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2051","DOI":"10.1002\/dvdy.22705","article-title":"Requirements for mediator complex subunits distinguish three classes of notch target genes at the Drosophila wing margin","volume":"240","author":"Janody","year":"2011","journal-title":"Dev. Dyn."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"ra30","DOI":"10.1126\/scisignal.2005892","article-title":"Site-specific methylation of Notch1 controls the amplitude and duration of the Notch1 response","volume":"8","author":"Hein","year":"2015","journal-title":"Sci. Signal"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1038\/nature09917","article-title":"Acetylation-dependent regulation of endothelial Notch signalling by the SIRT1 deacetylase","volume":"473","author":"Guarani","year":"2011","journal-title":"Nature"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1016\/j.cell.2007.12.016","article-title":"Rumi is a CAP10 domain glycosyltransferase that modifies Notch and is required for Notch signaling","volume":"132","author":"Acar","year":"2008","journal-title":"Cell"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1599","DOI":"10.1126\/science.1108995","article-title":"Chaperone activity of protein O-fucosyltransferase 1 promotes notch receptor folding","volume":"307","author":"Okajima","year":"2005","journal-title":"Science"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1347","DOI":"10.1242\/dev.02811","article-title":"The O-fucosyltransferase O-fut1 is an extracellular component that is essential for the constitutive endocytic trafficking of Notch in Drosophila","volume":"134","author":"Sasamura","year":"2007","journal-title":"Development"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"4122","DOI":"10.1074\/jbc.M109.016964","article-title":"Two pathways for importing GDP-fucose into the endoplasmic reticulum lumen function redundantly in the O-fucosylation of Notch in Drosophila","volume":"285","author":"Ishikawa","year":"2010","journal-title":"J. Biol. Chem."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"908","DOI":"10.1038\/43191","article-title":"Fringe modulates Notch-ligand interactions","volume":"387","author":"Panin","year":"1997","journal-title":"Nature"},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Cammarata-Mouchtouris, A., Nguyen, X.H., Acker, A., Bonnay, F., Goto, A., Orian, A., Fauvarque, M.O., Boutros, M., Reichhart, J.M., and Matt, N. (2020). Hyd ubiquitinates the NF-\u03baB co-factor Akirin to operate an effective immune response in Drosophila. PLoS Pathog., 16.","DOI":"10.1371\/journal.ppat.1008458"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1073\/pnas.0403497101","article-title":"Notch signaling in Drosophila long-term memory formation","volume":"101","author":"Ge","year":"2004","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"310","DOI":"10.1073\/pnas.0807665106","article-title":"The Drosophila cell adhesion molecule klingon is required for long-term memory formation and is regulated by Notch","volume":"106","author":"Matsuno","year":"2009","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Lin, C., Li, M., Lin, N., Zong, J., Pan, J., and Ye, Y. (2022). RNF38 suppress growth and metastasis via ubiquitination of ACTN4 in nasopharyngeal carcinoma. BMC Cancer, 22.","DOI":"10.1186\/s12885-022-09641-x"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1139\/bcb-2021-0093","article-title":"RNF38 inhibits osteosarcoma cell proliferation by binding to CRY1","volume":"99","author":"Zhou","year":"2021","journal-title":"Biochem. Cell Biol."},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Pan, Y., Zeng, W., Liang, T., Nie, X., Liu, K., Chen, H., Luo, N., Zhu, X., Tian, K., and Chen, Y. (2024). RNF38 promotes gilteritinib resistance in acute myeloid leukemia via inducing autophagy by regulating ubiquitination of LMX1A. Cell Biol. Toxicol., 40.","DOI":"10.1007\/s10565-024-09936-8"},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"1806","DOI":"10.1002\/1878-0261.12151","article-title":"Degradation of AMPK-\u03b11 sensitizes BRAF inhibitor-resistant melanoma cells to arginine deprivation","volume":"11","author":"Li","year":"2017","journal-title":"Mol. Oncol."}],"container-title":["Biomolecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2218-273X\/15\/8\/1082\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:16:33Z","timestamp":1760033793000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2218-273X\/15\/8\/1082"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,26]]},"references-count":57,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2025,8]]}},"alternative-id":["biom15081082"],"URL":"https:\/\/doi.org\/10.3390\/biom15081082","relation":{},"ISSN":["2218-273X"],"issn-type":[{"type":"electronic","value":"2218-273X"}],"subject":[],"published":{"date-parts":[[2025,7,26]]}}}