Messenger RNAs (mRNAs) accumulate at centrosomes in mitosis and interphase, yet the mechanisms governing their localization and the functional significance of centrosomal localization remain poorly understood. Here, we investigate the regulation and function of the centrosome-localized mRNA, CEP350 . We find that CEP350 mRNA localizes to centrosomes during S phase via the centriolar satellite protein CEP131 and the RNA binding protein (RBP) Unkempt (UNK), in a microtubule (MT)-dependent manner. CEP131 and UNK stabilize CEP350 mRNA to maintain CEP350 mRNA steady-state levels. Furthermore, CEP131 and UNK promote normal CEP350 protein levels at centrosomes. CEP350 is required for PLK4-induced centriole overduplication but is less important for canonical centriole duplication. Moreover, CEP131, UNK, and CEP350 are important for centrosome amplification in triple-negative breast cancer cells. Together, these findings reveal a centriolar satellite-RBP pathway regulating CEP350 mRNA localization to centrosomes. Significance Statement ### Competing Interest Statement The authors have declared no competing interest. * RBP : RNA binding protein CA : Centrosome amplification MT : Microtubule smiFISH : single molecule inexpensive fluorescence in situ hybridization National Institute of General Medical Sciences, https://ror.org/04q48ey07, R35 GM140813 W.M. Keck Science Center, https://ror.org/05sy8gb82, 211402
Erroneous loading of the ring-shaped cohesin complex, especially at centromeres, cause chromosomal segregation defects in both mitosis and meiosis. Mitotic cohesin subunits of this complex, either get replaced or co-exist with their meiotic paralogs during meiosis and also in certain cancers. However, it is unclear whether meiotic paralogs can partner mitotic subunits to form hybrid complexes in somatic cells and if there are any functional consequences on cancer progression. Here, we provide a conceptual framework for the principles of cohesin complex assembly involving non-canonical subunits in proliferating Schizosaccharomyces pombe. We show that chromosome loading, segregation fidelity and cellular proliferation are critically affected by the composition of the available cohesin complexes. We find stark differences in the ability of the meiotic kleisin subunit Rec8 to support robust centromere loading, irrespective of its partner, when compared to the canonical mitotic paralog Rad21. Such variations in cellular growth can be explained by different dwell times of these cohesin complexes on the chromosomes as determined by single-molecule tracking and altered chromatin enrichment. We also discover a unique feature of Rec8, in stabilizing chromatin-bound hypomorphic cohesin mutants that aid in cell survival under restrictive conditions. Overall, we highlight the flexibility of meiotic cohesins in restoring function, albeit at a fitness cost, in the presence of inactivating cohesin mutations. Such imbalances could be exploited by cancers to aid cell survival, but at the expense of increased aneuploidy and genomic instability. ### Competing Interest Statement The authors have declared no competing interest. Wellcome Trust/DBT India Alliance, https://ror.org/04reqzt68, IA/I/23/1/506752 Science and Engineering Research Board, https://ror.org/03ffdsr55, SPG/2022/000881 Department of Biotechnology, https://ror.org/03tjsyq23, BT/PR54475/BSA/33/357/2024(CN21105)
Animal development is a complex process that requires the coordination of a plethora of pathways in space and time. In several species, the availability of tissue explants has provided a simplified context that facilitates mechanistic investigations, particularly into dynamic events. Here, we demonstrate that extruded C. elegans gonads are a viable tissue explant system for this model organism. Using live-cell imaging, we show that C. elegans gonad explants retain many tissue properties that have been documented in vivo, including mitosis, meiosis, apoptosis and gametogenesis. We further show that C. elegans explants are acutely responsive to treatment by the microtubule depolymerizing drug nocodazole. Our work thus reveals C. elegans gonad explants as a new system in which live-cell imaging and acute drug treatment can be combined to decipher the mechanisms governing germline development. ### Competing Interest Statement The authors have declared no competing interest. Canadian Institutes of Health Research, PJT-525829
Messenger RNAs (mRNAs) accumulate at centrosomes in mitosis and interphase, yet the mechanisms governing their localization and the functional significance of centrosomal localization remain poorly understood. Here, we investigate the regulation and function of the centrosome-localized mRNA, CEP350 . We find that CEP350 mRNA localizes to centrosomes during S phase via the centriolar satellite protein CEP131 and the RNA binding protein (RBP) Unkempt (UNK), in a microtubule (MT)-dependent manner. CEP131 and UNK stabilize CEP350 mRNA to maintain CEP350 mRNA steady-state levels. Furthermore, CEP131 and UNK promote normal CEP350 protein levels at centrosomes. CEP350 is required for PLK4-induced centriole overduplication but is less important for canonical centriole duplication. Moreover, CEP131, UNK, and CEP350 are important for centrosome amplification in triple-negative breast cancer cells. Together, these findings reveal a centriolar satellite-RBP pathway regulating CEP350 mRNA localization to centrosomes. Significance Statement ### Competing Interest Statement The authors have declared no competing interest. * RBP : RNA binding protein CA : Centrosome amplification MT : Microtubule smiFISH : single molecule inexpensive fluorescence in situ hybridization National Institute of General Medical Sciences, https://ror.org/04q48ey07, R35 GM140813 W.M. Keck Science Center, https://ror.org/05sy8gb82, 211402
Rxiv mechanobio