Gamete fusion triggers bipartite transcription factor assembly to block re-fertilization.

Détails

ID Serval
serval:BIB_A21FBFE6711F
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Gamete fusion triggers bipartite transcription factor assembly to block re-fertilization.
Périodique
Nature
Auteur(s)
Vještica A., Merlini L., Nkosi P.J., Martin S.G.
ISSN
1476-4687 (Electronic)
ISSN-L
0028-0836
Statut éditorial
Publié
Date de publication
08/2018
Peer-reviewed
Oui
Volume
560
Numéro
7718
Pages
397-400
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Résumé
The ploidy cycle, which is integral to sexual reproduction, requires meiosis to halve chromosome numbers as well as mechanisms that ensure zygotes are formed by exactly two partners <sup>1-4</sup> . During sexual reproduction of the fungal model organism Schizosaccharomyces pombe, haploid P and M cells fuse to form a diploid zygote that immediately enters meiosis <sup>5</sup> . Here we reveal that rapid post-fusion reconstitution of a bipartite transcription factor blocks re-fertilization. We first identify mutants that undergo transient cell fusion involving cytosol exchange but not karyogamy, and show that this drives distinct cell fates in the two gametes. The P partner undergoes lethal haploid meiosis, whereas the M cell persists in mating. The zygotic transcription that drives meiosis is rapidly initiated first from the P parental genome, even in wild-type cells. This asymmetric gene expression depends on a bipartite complex formed post-fusion between the cytosolic M-cell-specific peptide Mi and the nuclear P-cell-specific homeobox protein Pi <sup>6,7</sup> , which captures Mi in the P nucleus. Zygotic transcription is thus poised to initiate in the P nucleus as fast as Mi reaches it after fusion, a design that we reconstruct using two synthetic interactors localized to the nucleus and the cytosol of two respective partner cells. Notably, delaying zygotic transcription-by postponing Mi expression or deleting its transcriptional target in the P genome-leads to zygotes fusing with additional gametes, thus forming polyploids and eventually aneuploid progeny. The signalling cascade to block re-fertilization shares components with, but bifurcates from, meiotic induction <sup>8-10</sup> . Thus, a cytoplasmic connection upon gamete fusion leads to asymmetric reconstitution of a bipartite transcription factor to rapidly block re-fertilization and induce meiosis, ensuring genome maintenance during sexual reproduction.
Mots-clé
Aneuploidy, Cell Fusion, Cell Nucleus/metabolism, Cytoplasm/metabolism, Diploidy, Gene Expression Regulation, Fungal, Haploidy, Meiosis/genetics, Polyploidy, Reproduction/genetics, Schizosaccharomyces/cytology, Schizosaccharomyces/genetics, Schizosaccharomyces pombe Proteins/metabolism, Signal Transduction, Transcription Factors/chemistry, Transcription Factors/metabolism, Transcription, Genetic
Pubmed
Web of science
Création de la notice
20/08/2018 15:00
Dernière modification de la notice
08/04/2019 6:26
Données d'usage