1
|
Saltel F, Giese A, Azzi L, Elatmani H, Costet P, Ezzoukhry Z, Dugot-Senant N, Miquerol L, Boussadia O, Wodrich H, Dubus P, Jacquemin-Sablon H. Unr defines a novel class of nucleoplasmic reticulum involved in mRNA translation. J Cell Sci 2017; 130:1796-1808. [PMID: 28386023 DOI: 10.1242/jcs.198697] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 03/31/2017] [Indexed: 12/23/2022] Open
Abstract
Unr (officially known as CSDE1) is a cytoplasmic RNA-binding protein with roles in the regulation of mRNA stability and translation. In this study, we identified a novel function for Unr, which acts as a positive regulator of placental development. Unr expression studies in the developing placenta revealed the presence of Unr-rich foci that are apparently located in the nuclei of trophoblast giant cells (TGCs). We determined that what we initially thought to be foci, were actually cross sections of a network of double-wall nuclear membrane invaginations that contain a cytoplasmic core related to the nucleoplasmic reticulum (NR). We named them, accordingly, Unr-NRs. Unr-NRs constitute a novel type of NR because they contain high levels of poly(A) RNA and translation factors, and are sites of active translation. In murine tissues, Unr-NRs are only found in two polyploid cell types, in TGCs and hepatocytes. In vitro, their formation is linked to stress and polyploidy because, in three cancer cell lines, cytotoxic drugs that are known to promote polyploidization induce their formation. Finally, we show that Unr is required in vivo for the formation of Unr-containing NRs because these structures are absent in Unr-null TGCs.
Collapse
Affiliation(s)
- Frédéric Saltel
- INSERM UMR1053 Bordeaux Research In Translational Oncology, BaRITOn, F-33000 Bordeaux, France .,University of Bordeaux, F-33000 Bordeaux, France
| | - Alban Giese
- INSERM UMR1053 Bordeaux Research In Translational Oncology, BaRITOn, F-33000 Bordeaux, France.,University of Bordeaux, F-33000 Bordeaux, France
| | - Lamia Azzi
- INSERM UMR1053 Bordeaux Research In Translational Oncology, BaRITOn, F-33000 Bordeaux, France.,University of Bordeaux, F-33000 Bordeaux, France.,Department of Tumor Biology, CHU, F-33000 Bordeaux, France
| | - Habiba Elatmani
- INSERM UMR1053 Bordeaux Research In Translational Oncology, BaRITOn, F-33000 Bordeaux, France.,University of Bordeaux, F-33000 Bordeaux, France
| | - Pierre Costet
- Laboratoire de Transgenèse, Université Bordeaux, F-33000 Bordeaux, France
| | - Zakaria Ezzoukhry
- INSERM UMR1053 Bordeaux Research In Translational Oncology, BaRITOn, F-33000 Bordeaux, France.,University of Bordeaux, F-33000 Bordeaux, France
| | | | - Lucile Miquerol
- Aix-Marseille University, CNRS, IBDM UMR 7288, Marseille, France
| | | | - Harald Wodrich
- University of Bordeaux, F-33000 Bordeaux, France.,MFP CNRS UMR 5234, Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, F-33000 Bordeaux, France
| | - Pierre Dubus
- INSERM UMR1053 Bordeaux Research In Translational Oncology, BaRITOn, F-33000 Bordeaux, France.,University of Bordeaux, F-33000 Bordeaux, France.,Department of Tumor Biology, CHU, F-33000 Bordeaux, France
| | - Hélène Jacquemin-Sablon
- INSERM UMR1053 Bordeaux Research In Translational Oncology, BaRITOn, F-33000 Bordeaux, France .,University of Bordeaux, F-33000 Bordeaux, France
| |
Collapse
|