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Recent publications

Quand ? Le 15/12/2020
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Comment des cellules aplatissent leurs voisines ? Dans le follicule ovarien de drosophile, la pression cytoplasmique des cellules germinales (noires) augmente progressivement et comprime au fur et à mesure les cellules de l’épithélium (rose). Celles-ci étant contraintes par une lame basale (vert), s’aplatissent.

 

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  • 4D Nucleome modeling. Marco Di Stefano, Jonas Paulsen, Daniel Jost, Marc A Marti-Renom (2021), Current Opinion in Genetics & Development 67: 25-32.

 

The intrinsic dynamic nature of chromosomes is emerging as a fundamental component in regulating DNA transcription, replication, and damage-repair among other nuclear functions. This review aims at giving to experimental biologists a clear understanding of the diverse theoretical modeling approaches available in 4D Genomics and the biological information each of them can provide.

 

 

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Some news on the cell biology and reproduction of Mesorhabditis nematodes. In this article published in the summer of 2020, we described >60 new isolates of Mesorhabditis nematodes, an astonishing group in which females use males for reproduction but get rid of their genes. In these species, the sperm DNA is set aside after fertilization and only the paternally provided centrioles contribute to zygote development (upper panel). Females produce few males at low frequency (10%), which ensures the reproduction of the species. Using rDNA sequencing and crosses, we identified 11 distinct biological species. Hence, we discovered that speciation occurs in such a reproductive state. We then asked what could be at the origin of hybrid incompatibility and species barrier in such a system where parental genomes do not experience genetic conflicts. We uncovered that centrosomes are not formed properly after fertilization in hybrids (lower panel). In regular species, when centrosomes are contributed paternally, the sperm provides centrioles which recruit the maternal pericentriolar material. Our results suggest a defect in the reconstitution of centrosomes in hybrids. That centrosomes may be involved in a species barrier is a surprising finding.

 

Strains were initially isolated by our collaborator Marie-Anne Félix from IBENS, Paris. Caroline Launay did an amazing job establishing the collection of 70 frozen samples, describing their morphology, performing hundreds of crosses, sequencing each isolate. Joris Dieng, a M2 intern in the spring of 2019 and Marie Delattre analysed the hybrids in more details.

 

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  • Best practices for the visualization, mapping, and manipulation of R-loops. Frédéric Chédin, Stella R. Hartono, Lionel A. Sanz and Vincent Vanoosthuyse (2021) The EMBO Journal (in press).

 

We review the main existing methodologies for R-loop mapping, and assess their limitations as well as the robustness of existing datasets. We offer a set of best practices to improve the reproducibility of maps and we propose a possible resolution for the apparent contradictions in R-loop mapping outcomes between antibody-based and RNase H1-based mapping approaches.

 

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Dysregulation of NF-κB signaling by inflammation or viruses has long been linked to profound transcriptional changes that contribute to human disease development. In the context of HTLV-1 infection, we (team ReGArDS) have recently identified that, besides its transcriptional activity, the NF-κB factor RELA provides dynamic splicing specificity by recruiting to gene bodies the splicing factor DDX17, which regulates inclusion of the nearby exon at the RNA level.