RESUMO
Regulated recruitment and activity of motor proteins is essential for intracellular transport of cargoes, including messenger ribonucleoprotein complexes (RNPs). Here, we show that orchestration of oskar RNP transport in the Drosophila germline relies on interplay between two double-stranded RNA-binding proteins, Staufen and the dynein adaptor Egalitarian (Egl). We find that Staufen antagonizes Egl-mediated transport of oskar mRNA by dynein both in vitro and in vivo. Following delivery of nurse cell-synthesized oskar mRNA into the oocyte by dynein, recruitment of Staufen to the RNPs results in dissociation of Egl and a switch to kinesin-1-mediated translocation of the mRNA to its final destination at the posterior pole of the oocyte. We additionally show that Egl associates with staufen (stau) mRNA in the nurse cells, mediating its enrichment and translation in the ooplasm. Our observations identify a novel feed-forward mechanism, whereby dynein-dependent accumulation of stau mRNA, and thus protein, in the oocyte enables motor switching on oskar RNPs by downregulating dynein activity.
Assuntos
Proteínas de Drosophila , Transporte de RNA , Animais , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Dineínas/genética , Dineínas/metabolismo , Cinesinas/genética , Cinesinas/metabolismo , Oócitos/metabolismo , Ribonucleoproteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismoRESUMO
BACKGROUND: Managing double-expressor lymphomas (DEL) is controversial given the dearth of data and lack of standardized guidelines on this high-risk subset of lymphomas. No prospective and few retrospective studies limited by either their sample size or short follow-up address the question of initial treatment of choice for DEL. We performed the largest analysis to date exploring R-CHOP vs DA-EPOCH-R in DEL. METHODS: Adults with DEL diagnosed from 6/2012-2/2021 at 4 unique sites were retrospectively analyzed. Progression-free survival (PFS) was the primary endpoint. Key secondary endpoints include overall survival (OS), overall and complete response rates (ORR and CRR), cumulative incidence of relapse, and autologous hematopoietic cell transplantation (autoHCT) utilization. RESULTS: 155 patients were included, 61 treated with R-CHOP and 94 with DA-EPOCH-R. 3-year PFS and OS were similar between R-CHOP and DA-EPOCH-R, 33.2% vs 57.2%,(P = .063), and 72.2% vs 71.6% (P = .43) after median follow-up times of 2.43 and 2.89 years, respectively. Patients <65 had improved PFS with DA-EPOCH-R, hazard ratio 0.41 (P = .01). CRR and ORR rates were also similar. Relapse rates were not statistically different, 51.9% vs 28.6% (P = .069). AutoHCT utilization was higher with R-CHOP vs DA-EPOCH-R, 23.0% vs 8.5% (P = .017). CONCLUSIONS: Our findings do not support the use of DA-EPOCH-R over R-CHOP for DEL. Patients <65 years may experience longer PFS with DA-EPOCH-R, but limitations to the analysis make this interpretation difficult.