Close

Lineage-specific CDK activity dynamics characterize early mammalian development

Bechara Saykali, Andy D. Tran, James A. Cornwell, Matthew A. Caldwell, Paniz Rezvan Sangsari, Nicole Y. Morgan, Michael J. Kruhlak, Steven D. Cappell, Sergio Ruiz

Posted on: 2 August 2024

Preprint posted on 14 June 2024

Catch them in the act : the swing of CDKs

Selected by Mansi

Categories: developmental biology

Background:  In mammals, the pre-implantation embryo takes all the big decisions on its own. Cell-cycle is the force driving it towards becoming a completely autonomous entity, with two distinct cell-types – the trophoectoderm (TE) and the inner cell mass (ICM). The cell-cycle is different between the embryo and the somatic cells, even though cyclins and cyclin-dependent kinases (CDKs) are involved in both. In this preprint, the authors turned into cinematographers, capturing the real time dynamics of CDKs using a very sensitive sensor.

Key findings of the study:

Generating the mouse model – Generating genetically modified mouse lines is a difficult task. A good reporter for studying cell-cycle dynamics in the pre-implantation embryo should capture  – low levels of protein, the dynamics of protein at single-cell level and rapid changes in the subcellular localisation of the protein.

The authors achieved all of these by stitching five DNA elements together –

  1. A portion of DNA human helicase B (DHB) containing four CDK phosphorylation sites
  2. Fluorescent protein mClover3
  3. Self-cleaving T2A peptide sequence
  4. Histone 2B (H2B) tag
  5. Fluorescent protein mRuby3

The CDK activity increases from G0/G1-S-G2/M phase and the mClover reporter translocate between the nucleus (low activity) and the cytoplasm (high activity) in a CDK-dependent manner, providing a quantifiable readout of CDK activity at a single-cell level.

Developmental stage specific CDK activity – The signal from the CDK sensor was apparent in the cytoplasm during the morula and mid-blastocyst stages suggesting high CDK activity. The late blastocyst has three major cell types – outer trophoblast layer (CDX2+), the epiblast (NANOG+), and the primitive endoderm layer (GATA6+). The authors made several fascinating observations giving us a peek into molecular events that are otherwise hard to probe. CDK activity decreased in the outer trophoblast as the embryo made preparations for  implanting itself in the uterus, however CDK activity remained high in the epiblast and primitive endoderm cells.

The molecule that causes the dip in CDK activity in the trophoblast – Interestingly, the three cell-types present in the blastocyst can be maintained in-vitro as self-renewing stem cells. To achieve this, trophoblast stem cells (TSCs) rely on fibroblast growth factor 4 (FGF4) whereas embryonic stem cells (ESCs) require leukaemia inhibitory factor (LIF) to self-renew. The authors performed FGF4 or LIF withdrawal experiments on TSCs and ESCs respectively and found that TSC were intrinsically more prone than ESC to downregulate CDK activity upon changes in the levels of self-renewing signals. This simple experiment offers a fundamental finding which the field lacked for a long-time.

Conservation of lineage-specific regulation of CDK activity in human TE-like cells –  The authors, leveraging their experimental strengths, used a 2D system to mimic human gastrulation to study CDK dynamics in human TE-like cells. The human ESCs were cultured in the circular micropatterned chip and stimulated with BMP4 to induce differentiation. The outermost ring of TE-like cells (CDX2+) showed nuclear enrichment of the CDK reporter, consistent with the observations in mouse embryo.

What I like about the preprint:

This preprint describes a beautiful tool that can be used to understand cell-cycle dynamics in early embryogenesis. Recently, there has been an explosion of papers that describe self-organising properties of stem cells into embryo-like structures. But how exactly do cells self-organise? The tool  described here can potentially be used to address some of the fundamental processes underlying self-organisation, and the autonomous developmental potential that stem cells carry. It is an elegantly designed system which can be used very easily and efficiently. The authors have used it to reveal the differences in cell cycle dynamics between ESCs and TSCs, which in itself is intriguing.

 

doi: https://doi.org/10.1242/prelights.38013

Read preprint (No Ratings Yet)

Author's response

Sergio Ruiz shared

Questions for the Authors:

 

  1. There is a huge metabolic shift that accompanies morula to blastocyst transition. Does the CDK activity depend on the metabolic state of the cell? For example, what would happen to CDK activity if the embryo is transiently deprived of amino-acids or glycolysis is moderately inhibited ?

Adaptative changes during embryonic development in metabolism are intimately coordinated with regulators of the cell cycle. Indeed, CDKs can directly or indirectly influence the regulation of metabolic pathways and vice versa. In our experimental setting, detecting changes in CDK activity in cells of the TE, could reflect changes in their metabolism. By the same token, changes in the levels of external nutrients affect the metabolic and proliferative state of the blastocyst. When embryos experience nutrient deprivation or certain experimental conditions such as the use of mTOR inhibitors, they can enter a state of diapause, where development temporarily halts. In this state, cells from the inner cell mass (ICM) and the TE, enter a transient G0/G1 state which is predicted to show nuclear localization of the CDK reporter. We are looking forward to test our model in an system of induced diapause. This will help us to examine the regulation of CDK activity during embryonic arrest, and the subsequent resumption in development following the removal of the diapause trigger.

 

  1. What would happen to the CDK activity in polar and mural TE cells if the FGF gradients along the embryonic-abembryonic axis is disrupted ?

We wondered that ourselves too! We set out to answer this question by supplying exogenous FGF4 to blastocysts prior to the moment we observed the CDK activity decrease in the TE. As predicted, we showed that exogenous FGF4 was able to rescue the drop on CDK activity in the mural TE. We are currently exploring the effects of adding to the blastocyst specific inhibitors targeting FGF receptors to examine CDK activity dynamics. But that’s not all! We are also testing the relevance of the FGF pathway in regulating the translocation of the CDK reporter in the 2D system mimicking human gastrulation.

 

Have your say

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Sign up to customise the site to your preferences and to receive alerts

Register here

Also in the developmental biology category:

Specialized signaling centers direct cell fate and spatial organization in a limb organoid model

Evangelia Skoufa, Jixing Zhong, Oliver Kahre, et al.

Selected by 05 September 2024

Ryan Harrison

Developmental Biology

Adult caudal fin shape is imprinted in the embryonic fin fold

Eric Surette, Joan Donahue, Stephanie Robinson, et al.

Selected by 28 August 2024

Isabella Cisneros

Developmental Biology

TAK1 operates at the primary cilium in non-canonical TGFB/BMP signaling to control heart development

Canan Doganli, Daniel A. Baird, Yeasmeen Ali, et al.

Selected by 16 August 2024

Reinier Prosee

Developmental Biology

preLists in the developmental biology category:

BSDB/GenSoc Spring Meeting 2024

A list of preprints highlighted at the British Society for Developmental Biology and Genetics Society joint Spring meeting 2024 at Warwick, UK.

 



List by Joyce Yu, Katherine Brown

GfE/ DSDB meeting 2024

This preList highlights the preprints discussed at the 2024 joint German and Dutch developmental biology societies meeting that took place in March 2024 in Osnabrück, Germany.

 



List by Joyce Yu

‘In preprints’ from Development 2022-2023

A list of the preprints featured in Development's 'In preprints' articles between 2022-2023

 



List by Alex Eve, Katherine Brown

preLights peer support – preprints of interest

This is a preprint repository to organise the preprints and preLights covered through the 'preLights peer support' initiative.

 



List by preLights peer support

The Society for Developmental Biology 82nd Annual Meeting

This preList is made up of the preprints discussed during the Society for Developmental Biology 82nd Annual Meeting that took place in Chicago in July 2023.

 



List by Joyce Yu, Katherine Brown

CSHL 87th Symposium: Stem Cells

Preprints mentioned by speakers at the #CSHLsymp23

 



List by Alex Eve

Journal of Cell Science meeting ‘Imaging Cell Dynamics’

This preList highlights the preprints discussed at the JCS meeting 'Imaging Cell Dynamics'. The meeting was held from 14 - 17 May 2023 in Lisbon, Portugal and was organised by Erika Holzbaur, Jennifer Lippincott-Schwartz, Rob Parton and Michael Way.

 



List by Helen Zenner

9th International Symposium on the Biology of Vertebrate Sex Determination

This preList contains preprints discussed during the 9th International Symposium on the Biology of Vertebrate Sex Determination. This conference was held in Kona, Hawaii from April 17th to 21st 2023.

 



List by Martin Estermann

Alumni picks – preLights 5th Birthday

This preList contains preprints that were picked and highlighted by preLights Alumni - an initiative that was set up to mark preLights 5th birthday. More entries will follow throughout February and March 2023.

 



List by Sergio Menchero et al.

CellBio 2022 – An ASCB/EMBO Meeting

This preLists features preprints that were discussed and presented during the CellBio 2022 meeting in Washington, DC in December 2022.

 



List by Nadja Hümpfer et al.

2nd Conference of the Visegrád Group Society for Developmental Biology

Preprints from the 2nd Conference of the Visegrád Group Society for Developmental Biology (2-5 September, 2021, Szeged, Hungary)

 



List by Nándor Lipták

Fibroblasts

The advances in fibroblast biology preList explores the recent discoveries and preprints of the fibroblast world. Get ready to immerse yourself with this list created for fibroblasts aficionados and lovers, and beyond. Here, my goal is to include preprints of fibroblast biology, heterogeneity, fate, extracellular matrix, behavior, topography, single-cell atlases, spatial transcriptomics, and their matrix!

 



List by Osvaldo Contreras

EMBL Synthetic Morphogenesis: From Gene Circuits to Tissue Architecture (2021)

A list of preprints mentioned at the #EESmorphoG virtual meeting in 2021.

 



List by Alex Eve

EMBL Conference: From functional genomics to systems biology

Preprints presented at the virtual EMBL conference "from functional genomics and systems biology", 16-19 November 2020

 



List by Jesus Victorino

Single Cell Biology 2020

A list of preprints mentioned at the Wellcome Genome Campus Single Cell Biology 2020 meeting.

 



List by Alex Eve

Society for Developmental Biology 79th Annual Meeting

Preprints at SDB 2020

 



List by Irepan Salvador-Martinez, Martin Estermann

FENS 2020

A collection of preprints presented during the virtual meeting of the Federation of European Neuroscience Societies (FENS) in 2020

 



List by Ana Dorrego-Rivas

Planar Cell Polarity – PCP

This preList contains preprints about the latest findings on Planar Cell Polarity (PCP) in various model organisms at the molecular, cellular and tissue levels.

 



List by Ana Dorrego-Rivas

Cell Polarity

Recent research from the field of cell polarity is summarized in this list of preprints. It comprises of studies focusing on various forms of cell polarity ranging from epithelial polarity, planar cell polarity to front-to-rear polarity.

 



List by Yamini Ravichandran

TAGC 2020

Preprints recently presented at the virtual Allied Genetics Conference, April 22-26, 2020. #TAGC20

 



List by Maiko Kitaoka et al.

3D Gastruloids

A curated list of preprints related to Gastruloids (in vitro models of early development obtained by 3D aggregation of embryonic cells). Updated until July 2021.

 



List by Paul Gerald L. Sanchez and Stefano Vianello

ASCB EMBO Annual Meeting 2019

A collection of preprints presented at the 2019 ASCB EMBO Meeting in Washington, DC (December 7-11)

 



List by Madhuja Samaddar et al.

EDBC Alicante 2019

Preprints presented at the European Developmental Biology Congress (EDBC) in Alicante, October 23-26 2019.

 



List by Sergio Menchero et al.

EMBL Seeing is Believing – Imaging the Molecular Processes of Life

Preprints discussed at the 2019 edition of Seeing is Believing, at EMBL Heidelberg from the 9th-12th October 2019

 



List by Dey Lab

SDB 78th Annual Meeting 2019

A curation of the preprints presented at the SDB meeting in Boston, July 26-30 2019. The preList will be updated throughout the duration of the meeting.

 



List by Alex Eve

Lung Disease and Regeneration

This preprint list compiles highlights from the field of lung biology.

 



List by Rob Hynds

Young Embryologist Network Conference 2019

Preprints presented at the Young Embryologist Network 2019 conference, 13 May, The Francis Crick Institute, London

 



List by Alex Eve

Pattern formation during development

The aim of this preList is to integrate results about the mechanisms that govern patterning during development, from genes implicated in the processes to theoritical models of pattern formation in nature.

 



List by Alexa Sadier

BSCB/BSDB Annual Meeting 2019

Preprints presented at the BSCB/BSDB Annual Meeting 2019

 



List by Dey Lab

Zebrafish immunology

A compilation of cutting-edge research that uses the zebrafish as a model system to elucidate novel immunological mechanisms in health and disease.

 



List by Shikha Nayar
Close