Maternal mRNA decay is essential for the Maternal-to-Zygotic Transition (MZT), yet its impact on spatial regulation has remained largely unexplored. We identify Cth1 as the first maternally encoded RNA-decay factor regulated in a spatiotemporal manner outside the germline in zebrafish, driven by conserved 3′UTR cis-elements. RfxCas13d-mediated depletion of maternal cth1 revealed early developmental defects that could not be assessed with SpyCas9 mutants due to infertility from impaired gametogenesis. Mechanistically, Cth1 acts independently of zygotic genome activation, recognizing AU-rich motifs in maternal 3′UTRs to promote deadenylation and decay; deletion of these motifs or depletion of Cth1 stabilizes both reporter and endogenous transcripts. These findings establish Cth1 as a key component of the maternal program and provide the first direct evidence that spatially regulated mRNA decay, outside the germline, contributes to early vertebrate development.

Palabras clave

Spatio-temporal maternal RNAs, CRISPR-Cas13d, Zebrafish, MZT

Aspectos destacados

• Cth1 is a highly deposited maternal mRNA that undergoes rapid decay.
• 3’UTR of Cth1 drives its spatio-temporal dynamics.
• Cth1 is essential for gametogenesis and early embryonic development.
• CTH1 recognizes AU-rich elements in target 3′UTRs to trigger decay.

Las crestas neurales son una población celular multipotente cuya migración es esencial para la formación de numerosos tejidos y órganos durante el desarrollo embrionario. En este trabajo exploramos los mecanismos celulares, moleculares y físicos que coordinan su migración colectiva, permitiendo que grupos de células se desplacen de manera eficiente y dirigida. Analizamos cómo las interacciones célula-célula y las señales del microambiente regulan este proceso dinámico. Nuestros resultados aportan nuevas perspectivas sobre los principios que gobiernan los movimientos colectivos celulares y su importancia en la morfogénesis embrionaria.

Organogenesis requires a tight coordination between cell proliferation and cell differentiation. Although the genetic networks controlling root development and tissue specification are well described, how they are integrated with cell cycle progression remains unclear. In this talk, I will discuss how cell cycle dynamics are spatially organized in the root meristem, revealing a positional gradient of cell cycle duration. I will also address how developmental regulators contribute to shaping this gradient, linking stem cell maintenance with cell cycle progression. These findings provide a new framework for understanding how growth and patterning are coordinated during root development.

En plantas, el estudio del desarrollo de hojas se ha centrado principalmente en especies con hojas sencillas o lineales, habiendo aún muchas interrogantes sobre cómo se forman aquellas con morfología compleja. En esta charla, compartiremos nuestros avances empleando histología, superresolución de imágenes y transcriptómica espacial para entender el origen y desarrollo de la hoja en palma jipi (Carludovica spp.), una monocotiledónea tropical, con grandes hojas palmeadas disectadas, usadas para elaborar los famosos sombreros de Panamá.

In cereals, the specification of sequential meristematic cell identities and the subsequent establishment of a floral meristem precede flower formation. This complex developmental program requires transcriptional coordination to correctly specify cell lineages. We therefore sought to develop an atlas of the barley meristem featuring single-cell expression data with spatial resolution, with the hope that this atlas will help us to define developmental transitions or cell states with improved resolution.

Infertility affects approximately 15% of couples worldwide, with male infertility responsible for nearly half of cases. While dietary and metabolic factors influence reproduction, the molecular mechanisms linking metabolism to fertility remain unclear. Our research explores how cellular metabolism regulates embryonic testis differentiation and its long-term impact on adult fertility using mice. We focus on Sertoli cells, the somatic lineage that supports the germline and orchestrates testis development. Previous studies suggest embryonic Sertoli cells rely on glucose for identity maintenance. Here, we investigated how glucose metabolism regulates Sertoli cell differentiation and function. Using ex-vivo drug screening in embryonic mouse testes, we found that glucose metabolism in Sertoli cells primarily feeds into the hexosamine biosynthetic pathway (HBP) rather than glycolysis. The HBP, through the O-GlcNAc transferase OGT, facilitates protein O-GlcNAcylation, a key post-translational modification that regulates cellular processes, including gene expression and protein stability. To examine its role in testis development, we performed transcriptomic analysis on embryonic testes treated with the OGT inhibitor OSMI-1, revealing defects in Sertoli cell differentiation, testis cord organization, and germ cell survival. To explore this process in-vivo, we generated Sertoli cell-specific Ogt conditional knockout (cKO) mice. Loss of Ogt during the process of sex differentiation destabilized testicular fate and caused ovotestis formation, with reduced SOX9⁺ Sertoli cells and ectopic FOXL2⁺ pre-granulosa cells. Ogt cKO in later stages resulted in infertile mice, with smaller testes, and lacking germ cells in seminiferous tubules, highlighting O-GlcNAcylation’s essential role in Sertoli cell function. Our findings suggest that Sertoli cells prioritize glucose metabolism through the HBP to sustain O-GlcNAcylation, ensuring their differentiation, survival, and germline support. Disrupting this process leads to Sertoli cell dysfunction, germline loss, and ultimately, male infertility.

In this talk, I will discuss how interactions between tissues generate physical scenarios that are sensed, internalized, and translated by molecular machineries to coordinate collective cell behavior. Using collective cell migration in vivo as a framework, I will show how tissue-scale mechanics and bioelectric fields emerge during development, and how cells convert these cues into polarity, migration, and self-organization. Based on the data presented, I hope to stimulate discussion on the idea that robust morphogenesis emerges from feedback between physical tissue states and the molecular programs that fuel, interpret, and translate them into collective cell behaviors.

El aumento de la fragilidad asociado al envejecimiento se atribuye en parte a la disminución de la capacidad regenerativa de los tejidos y órganos. En este sentido, los animales con alta capacidad regenerativa tienden a mostrar un envejecimiento mínimo. El cnidario Hydra vulgaris es capaz de regenerar todo el cuerpo y parece no presentar signos de envejecimiento. Curiosamente, una especie estrechamente relacionada, Hydra oligactis, presenta un fenotipo asociado al envejecimiento en respuesta a la diferenciación sexual. En nuestro laboratorio estamos usando a estas dos especies de Hydra como sistema para abordar el estudio de la longevidad desde una aproximación de biología comparativa. Para ello, estamos caracterizando los signos característicos del envejecimiento en H. oligactis a nivel molecular. Por otro lado, estamos usando estrategias de genómica comparativa para esclarecer la evolución de los genes con un rol en estos signos característicos del envejecimiento a lo largo del árbol de Metazoarios desde una perspectiva del género Hydra, con el fin de entender cómo la longevidad ha sido moldeada a través de la evolución. Más aún, estamos tratando de describir la asociación que existe entre regeneración y envejecimiento usando estas mismas especies de Hydra.

The atypical cadherin Dachsous (Ds) regulates planar cell polarity (PCP) and organ growth, but its transcriptional control is poorly understood. We identified seven enhancers near the ds promoter that drive expression in ectoderm-derived tissues. While in vivo assays show these enhancers act redundantly during early embryogenesis, CRISPR/Cas9 deletion of a single enhancer produces distinct wing phenotypes in adult flies. These findings offer new insights into the transcriptional regulation underlying Drosophila development.