Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2019.12.19.882712

The R2TP chaperone assembles cellular machineries in intestinal CBC stem cells and progenitors

Maurizy, C.·Abeza, C.·Pinet, V.·Ferrand, M.·Paul, C.·Bremond, J.·Langa, F.·Gerbe, F.·Jay, P.·Verheggen, C.·Tinari, N.·Helmlinger, D.·Lattanzio, R.·Bertrand, E.·Hahne, M.·Pradet-Balade, B.
View original source ↗Export metadata ↓

Abstract

The R2TP chaperone cooperates with HSP90 to integrate newly synthesized proteins into multi-subunit complexes, yet its role in tissue homeostasis is unknown. Here, we generated conditional, inducible knock-out mice for Rpap3 to inactivate this core component of R2TP in the intestinal epithelium. In adult mice, Rpap3 invalidation caused destruction of the small intestinal epithelium, and death within 10 days. Levels of R2TP substrates were decreased, with strong effects on mTOR, ATM and ATR. Rpap3-deficient CBC stem cells and progenitors also failed to import RNA polymerase II in the nucleus. This correlated with p53 activation, cell cycle arrest and apoptosis. Interestingly, post-mitotic, differentiated cells did not display any of those alterations, indicating that R2TP clients are built in actively proliferating cells. Analyses of tissues from colorectal cancer patients revealed that high RPAP3 levels correlate with bad cancer prognosis. Thus, in the intestine, the R2TP chaperone functions in physiologic and pathologic proliferation.

Source connections

Explore related subjects

developmental biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Maurizy, C., Abeza, C., Pinet, V., Ferrand, M., Paul, C., Bremond, J., Langa, F., Gerbe, F., Jay, P., Verheggen, C., Tinari, N., Helmlinger, D., Lattanzio, R., Bertrand, E., Hahne, M., Pradet-Balade, B.. 2019-12-19. The R2TP chaperone assembles cellular machineries in intestinal CBC stem cells and progenitors. https://doi.org/10.1101/2019.12.19.882712

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Neogenin-1 marks myeloid-primed fetal hematopoietic stem cells that undergo progressive lineage-restriction with age

During aging, hematopoietic stem cells (HSCs) increasingly shift from balanced to myeloid-biased differentiation, resulting in reduced lymphoid output and impaired adaptive immunity. The question of whether this lineage bias is established in a subset of HSCs during early development or primarily emerges with aging warrants further investigation. Here, we investigate whether myeloid-biased HSCs (my-HSCs) are established at the fetal liver stage by specifically examining Neogenin-1 (NEO1), a previously defined marker of my-HSCs. We identify two distinct populations of Hoxb5+ HSCs in the fetal liver: NEO1+ and NEO1-, with NEO1+ HSCs exhibiting transcriptional and functional characteristics consistent with my-HSCs. With age, my-HSC-associated transcriptional programs become increasingly reinforced across the Hoxb5+ pHSC compartment, with NEO1+ cells showing early enrichment of this program and both NEO1+ and NEO1- cells acquiring broader myeloid-biased features in aging. These findings suggest that lineage programming can begin early in development and is further shaped by age-related changes, potentially contributing to the functional decline observed in the aging hematopoietic system.

developmental biology↗
bioRxiv2026

Distinct roles for partially redundant transcription factors in Caenorhabditis elegans mesoderm lineage development

Developmental transcription factors often have overlapping functions, making it difficult to define the distinct roles of individual factors during lineage specification. We investigated the partially redundant transcription factors TBX-35 and CEH-51 in the Caenorhabditis elegans embryonic MS mesodermal lineage using 4D lineage tracing, reporter imaging, genetics, and single-cell RNA sequencing. In tbx-35 mutants, MS descendants showed progressively slower cell cycles and a division pattern that increasingly resembled the cousin C lineage. Fate-regulator expression also shifted toward C-like features, including ectopic pal-1 and expanded HLH-1 expression, although mutant cells did not simply adopt normal C-lineage positions. Loss of tbx-35 also impaired a later MS-dependent Notch induction in the AB lineage while leaving an earlier induction intact. CEH-51 showed a different pattern of activity whereby its protein became enriched in anterior MS daughters, and ceh-51 mutants produced later, more restricted lineage defects that were strongest in descendants of cells with higher CEH-51 levels. Single-cell profiling identified overlapping but nonidentical sets of genes dependent on the two factors. TBX-35-dependent changes were strongest at earlier stages, whereas CEH-51-dependent genes became more prominent later and were enriched in anterior MS sublineages. Finally, temperature-shift experiments determined that the severity and onset of tbx-35 mutant phenotypes depend on the maternal temperature environment and cannot be explained by differences in residual CEH-51 expression. These findings reveal that TBX-35 and CEH-51 contribute differently across the MS lineage and that reliable mesoderm development is supported by overlapping zygotic and maternal regulatory inputs.

developmental biology↗
bioRxiv2026

Dynamic microtubules drive yolk-cytoplasm segregation in the syncytial Drosophila embryo

Yolk-cytoplasm segregation is among the earliest spatial organization events in the developing embryo of many oviparous animals. The segregation process is intimately linked to early embryonic cleavage and pattern formation, and exhibits a wide range of spatial and temporal diversity. However, the underlying cytoskeletal mechanism remains largely unknown, except for a small number of species. Using quantitative live imaging, we investigated yolk segregation in the Drosophila embryo during the syncytial nuclear cycles 11-14. We find that the yolk vesicles move progressively inward in spatial and temporal coordination with the inward expanding microtubule networks that are nucleated from centrosomes positioned at the cortex, whereas cortical actin meshwork remains spatially restricted. Using the gnu RNAi embryo to decouple nuclear migration and division from cytoskeletal dynamics, we establish causality with targeted pharmacological disruption and find that microtubule dynamics is required for yolk segregation, while depolymerization of actin has no discernible effect. In support of a mechanism of growth-propelled passive displacement, microtubule plus end comets come in apparent contact with yolk vesicles, and injected, inert microbeads are displaced towards the embryo center presumably by the same pushing force. These findings identify microtubule polymerization as a predominant driver of yolk-cytoplasm segregation in Drosophila and suggest that diverse cytoskeletal mechanisms evolved to accomplish this crucial reorganization process

developmental biology↗