Rayon Group

Rayon Group
Rayon Group
Teresa Rayon
Tenure Track Group Leader
Rayon Group

Research Summary

Teresa bridges two of the Institute’s research programmes, being jointly appointed to both the Epigenetics and Signalling programmes.

How do organisms keep track of time and what determines the lifespan of a species? The mechanisms that underlie biological timing remain largely unknown. Despite the high conservation of genetic programs throughout the animal kingdom, the duration of embryogenesis and lifespan are species-specific. For instance, mouse development lasts around 20 days, and the embryonic period of human gestation takes place during the first 60 days of pregnancy. This differences in timing arise at conception, as the progression from the fertilized zygote to embryo implantation lasts around four days in mouse whereas it takes seven days in human. Further, some species can halt development for extended periods of time (diapause) with no apparent trade-offs for development or lifespan.

Our lab studies the regulatory and dynamic processes that control timing in development and homeostasis across and within species with the long-term goal to modulate biological timing in a precise and tunable manner. Our current research questions are:

  1. What controls biological timing?
  2. Can we modulate developmental timing and extend lifespan?
  3. What is the role of protein turnover in developmental timing and lifespan?

We make use of comparative human and mouse stem cell models as well as embryos to search for the regulatory mechanisms that determine species-specific timing. The lab employs genetic and pharmacological manipulations and quantitative and temporally resolved techniques such as flow cytometry, imaging, and genome-wide approaches to investigate the molecular and metabolic mechanisms that regulate developmental timing.

Overall, the identification of physiological mechanisms that modulate timing and its translation to stem cell models may have important implications in the field of human assisted reproduction, regenerative medicine, and aging. Changing the pace of developmental processes may facilitate the generation of clinically relevant cell types faster or it may allow lifespan extension.

Stem Cell Development



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Latest Publications

Azzi C, Rayon T Signalling, Epigenetics

Temporal control is central to deploy and coordinate genetic programs during development. At present, there is limited understanding of the molecular mechanisms that govern the duration and speed of developmental processes. Timing mechanisms may run in parallel and/or interact with each other to integrate temporal signals throughout the organism. In this piece, we consider findings on the extrinsic control of developmental tempo and discuss the intrinsic roles of cell cycle, metabolic rates, protein turnover, and post-transcriptional mechanisms in the regulation of tempo during neural development.

+view abstract Current opinion in genetics & development, PMID: 38648722 21 Apr 2024

Nakanoh S, Sham K, Ghimire S, Mohorianu I, Rayon T, Vallier L Signalling, Epigenetics

Mechanisms specifying amniotic ectoderm and surface ectoderm are unresolved in humans due to their close similarities in expression patterns and signal requirements. This lack of knowledge hinders the development of protocols to accurately model human embryogenesis. Here, we developed a human pluripotent stem cell model to investigate the divergence between amniotic and surface ectoderms. In the established culture system, cells differentiated into functional amnioblast-like cells. Single-cell RNA sequencing analyses of amnioblast differentiation revealed an intermediate cell state with enhanced surface ectoderm gene expression. Furthermore, when the differentiation started at the confluent condition, cells retained the expression profile of surface ectoderm. Collectively, we propose that human amniotic ectoderm and surface ectoderm are specified along a common nonneural ectoderm trajectory based on cell density. Our culture system also generated extraembryonic mesoderm-like cells from the primed pluripotent state. Together, this study provides an integrative understanding of the human nonneural ectoderm development and a model for embryonic and extraembryonic human development around gastrulation.

+view abstract Science advances, PMID: 38427729 Mar 2024

Rayon T Epigenetics, Signalling

An overview on the molecular and metabolic mechanisms behind individual cell differences in developmental timing in the segmentation clock and the central nervous system.

+view abstract Science advances, PMID: 36888707 10 Mar 2023

Group Members

Teresa Rayon

Tenure Track Group Leader

Chiara Azzi

Postdoc Research Scientist

Loukik Doshi

Research Assistant

Shota Nakanoh

Postdoc Research Scientist

Eleonore Ocana

PhD Student

Max Perrin

Research Assistant