Gastruloids are 3D structures generated from pluripotent stem cells recapitulating fundamental principles of embryonic pattern formation. Using single-cell genomic analysis, we provide a resource mapping cell states and types during gastruloid development compare them with the in vivo embryo. We developed high-throughput handling imaging pipeline to spatially monitor symmetry breaking report an early spatial variability pluripotency determining binary response Wnt activation. Although...

Pioneer transcription factors are characterized by having the unique property of enabling opening closed chromatin sites, for implementation cell fates. We previously found that pioneer Pax7 specifies melanotrope cells through deployment an enhancer repertoire, which allows binding Tpit, a nonpioneer factor determines related lineages melanotropes and corticotropes. Here, we investigate relation between these two in mechanism. Cell-specific gene expression landscapes defined scRNAseq...

During development, Hox genes are temporally activated according to their relative positions on clusters, contributing the proper identities of structures along rostrocaudal axis. To understand mechanism underlying this timer, we used mouse embryonic stem cell-derived stembryos. Following Wnt signaling, process involves transcriptional initiation at anterior part cluster and a concomitant loading cohesin complexes enriched transcribed DNA segments, that is, with an asymmetric distribution...

Abstract Hox genes encode transcription factors (TFs) that establish morphological diversity in the developing embryo. The similar DNA-binding motifs of various HOX TFs contrast with wide-range HOX-dependent genetic programs. influence chromatin context on binding specificity remains elusive. Here, we used limb as a model system to compare HOXA13 and HOXD13 (HOX13 hereafter), which are required for digit formation, HOXA11, involved forearm/leg development. We find upon ectopic expression...

Abstract Translation is a basic cellular process and its capacity adapted to cell function. In particular, secretory cells achieve high protein synthesis levels without triggering the stress response. It unknown how when translation increased during differentiation. Here, we show that transcription factor Creb3l2 scaling for in pituitary it directly binds ~75% of regulatory effector genes translation. parallel with this cell-autonomous mechanism, implementation physiological UPR pathway...

Down syndrome (DS), caused by the triplication of human chromosome 21, leads to significant alterations in brain development and is a major genetic cause intellectual disability. While much known about changes neurons DS, effects trisomy 21 on non-neuronal cells such as astrocytes are poorly understood. Astrocytes critical for function, their alteration may contribute DS pathophysiology. To better understand impact astrocytes, we performed RNA-sequencing from newly produced induced...

Abstract The interplay between mechanical forces and genetic programs is fundamental to embryonic development, yet how these factors independently or jointly influence morphogenesis cell fate decisions remains poorly understood. Here, we fine-tune the environment of murine gastruloids, three-dimensional in vitro models early embryogenesis, by embedding them bioinert hydrogels with precisely tunable stiffness timing application. This approach reveals that external constraints can selectively...

Abstract The pioneer transcription factor Pax7 contains two DNA binding domains (DBD), a paired and homeo domain. Previous work on the related Pax3 showed that each DBD binds cognate sequence, thus defining targets of possibly modalities action. Genomic action leading to chromatin opening are enriched for composite target sites containing juxtaposed both domains. present investigated implication DBDs in We show sequence is higher affinity site efficient this involves same molecule. This not...

ABSTRACT Gastruloids have recently emerged as an efficient four-dimensional model for studying some aspects of post-implantation embryonic patterning. They undergo gastrulation-like processes leading to the self-organization into highly reproducible biological objects. Here, we sought uncover molecular and cellular mechanism underlying this remarkable property. We report that competence is associated with a cell-specific coordination Cadherin switch. find N-Cadherin hinders gastruloids...

Mammalian tail length is controlled by several genetic determinants, among which are Hox13 genes, whose function to terminate the body axis. Accordingly, precise timing in transcriptional activation of these genes may impact upon length. Unlike other Hox clusters, HoxB lacks posterior between Hoxb9 and Hoxb13 , two separated a ca. 70 kb large DNA segment containing high number CTCF sites, potentially isolating from rest cluster thereby delaying its negative on trunk extension. We deleted...

ABSTRACT In mammals, tail length is controlled by several genetic determinants, amongst which Hox13 genes located at the posterior extremities of Hox clusters, whose main function are to terminate extension body axis. this view, precise timing in transcriptional activation these may impact upon length. Unlike other HoxB lacks all between Hoxb9 and Hoxb13, two separated a ca. 70 kb large DNA segment containing an unusually high number CTCF sites, suggesting it isolates Hoxb13 from rest...

Understanding the interplay between cell fate specification and morphogenetic changes remains a central challenge in developmental biology. Gastruloids, self-organizing stem cell-based models of post-implantation mammalian development, provide powerful platform to address this question. Here, we show that physical parameters, particularly system size, critically influence timing outcomes processes. Larger gastruloids exhibit delayed symmetry breaking, increased multipolarity, prolonged axial...

Self-organization, such as the emergence of a pattern from homogenous state, is fascinating property biological systems. Early limb bud outgrowth and patterning in mice are controlled by robust self-regulatory signaling system, initiation periodic digit-interdigit appears under control Turing system. Previous studies established requirement WNT BMP for both early morphogenesis, but molecular changes underlying transition to system remained unknown. Here, we use small molecule inhibitors...

Abstract Pioneer transcription factors are coined as having the unique property of “opening closed chromatin sites” for implementation cell fates. We previously showed that pioneer Pax7 specifies melanotrope cells through deployment an enhancer repertoire: this allows binding Tpit, a nonpioneer factor determines related lineages melanotropes and corticotropes. Here, we investigated relation between these two in mechanism. Cell-specific gene expression landscapes were defined by scRNAseq...

ABSTRACT Hox genes encode essential transcription factors that control patterning during embryonic development. Distinct combinations of nested expression domains establish cell and tissue identities 1–3 . Consequently, spatial or temporal de-regulation can cause severe alterations the body plan 3 While HOX have very similar DNA binding motifs, their specificity is, in part, mediated by co-factors 4–6 Yet, interplay between specificities cellular context remains largely elusive. To gain...

Abstract The Polycomb Repressive Complexes (PRC) are key players in the regulation of tissue-specific gene expression through their ability to epigenetically silence developmental genes. They subdivided into two multicomponent complexes, PRC1 and PRC2, functioning post-translational modifications histone tails. A large body work revealed functional interactions between whereby trimethylation lysine 27 on H3 (H3K27me3) by PRC2 contributes recruitment canonical (cPRC1). In parallel, a...

Abstract Translation is a basic cellular process and its capacity adapted to cell function. In particular, secretory cells achieve high protein synthesis levels without triggering the stress response. It unknown how when translation increased during differentiation. Here, we show that transcription factor Creb3l2 scaling for in it directly binds ~75% of regulatory effector genes translation. parallel with this cell-autonomous mechanism, implementation physiological UPR pathway prevents The...

Preventing inappropriate gene expression in time and space is as fundamental triggering the activation of tissue/cell-type specific factors at correct developmental stage cells. While mechanisms Hox have been extensively studied, much less known about silencing. Here, we show that, addition to well-known function PRC2 silencing genes via direct binding, PRC2-dependent long-range contacts create a spatial chromatin organization preventing enhancer-promoter contacts, tissue-specific manner....

Abstract The pioneer transcription factor Pax7 contains two DNA binding domains (DBD), a paired and homeo domain. Previous work on the related Pax3 had shown that each DBD can bind cognate sequence, thus defining targets of possibly modalities action. Genomic action leading to chromatin opening are enriched for composite target sites containing juxtaposed both domains. present investigated implication DBDs in We now show sequence is higher affinity site compared either or efficient this...

The current pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected most of the world in a profound way. As an indirect consequence, general public been put into direct contact with research process, almost real time. Justifiably, lot this focus targeted toward directly linked to disease 2019 (COVID-19). In opinion article, we want highlight audience value having diverse "portfolio" approaches for society as whole. study, will on our field research,...