Chance does things right!

Chance does things right!


© Nicolas Allègre and Claire Chazaud

We all come from a single cell that first multiplies into identical cells and then differentiates from each other. After many stages of differentiation, cells as diverse as the skin (The skin is an organ made up of several layers of tissue. It plays, among other things, the …) ointestine (The intestine is the part of the digestive tract that extends from the exit of the stomach to …) occur. In a study published in the journal NaturaComunicacionesscientists show that the opportunity (In normal language, the word random is used to express a lack of efficiency, otherwise …) can decide the future identity of the cell.

During cell differentiation, identity changes are finely regulated by gene induction cascades, usually by internal upstream changes (e.g. activate (Activation can refer to 🙂 sequence of transcription factors) or external (molecular and / or mechanical exchanges with neighboring cells) in the cell. It is these upstream changes that determine the path of differentiation. However, in some cases chance may decide the future identity of the cell.

Some days (The day or the day is the interval that separates the sunrise from the sunset; it is the …) After the fertilization (Fertilization, for organized living beings, is the stage of reproduction …) (3 days al mouse (The term mouse is an ambiguous vernacular name that can designate, for Francophones, before …) and 6 in humans), the first cell differentiation of theembryo (An embryo (from the ancient Greek ἔμϐρυον / embruon) is …)separating future cells from placenta (The placenta is a unique organ that physically and biologically connects the embryo to …)it is done according to the position intern (In France, this name designates a doctor, a pharmacist or a dental surgeon, in …) or external to the cell, while the second cell differentiation of the epiblast (which produces all the cells of the future individual) depends on a random mechanism. To become an epiblast, a cell has need (The needs are at the level of the interaction between the individual and the environment. It is …) several specific transcription factors that cooperate to initiate differentiation. However, in progenitor cells prior to differentiation, these transcription factors have varying levels of expression from one cell to another in an uncoordinated manner. Chance will cause these factors to be found in a few cells out of about 25 together (In set theory, a set intuitively designates a collection …) at levels sufficient to cause differentiation. Only these cells can be transformed into an epiblast. Therefore, it is the random co-expression of these factors that would imply cell differentiation.

Scientists have identified one of these differentiating factors for epiblasts, NANOG, and have shown that without this factor there is no differentiation, the cells remain blocked in stage (A stadium (from the ancient Greek στ? Διον stadion, from the verb …) of progenitor, the development of the embryo stops. However, NANOG alone does not appear to be able to induce differentiation, demonstrating that only cooperation with other, as yet unknown, factors allows for this differentiation.

This random decision mechanism has been studied mainly in bacteria (Bacteria (bacteria) are living prokaryotic unicellular living organisms, characterized …) o al drosophila (Drosophila (from the Greek drosos: dew and philos: who loves) is an insect …) but it is still little explored in mammals although it is involved in hematopoiesis.

This discovery is closely linked to the research (Scientific research first designates all the actions carried out with the aim of …) on ES embryonic stem cells (2007 Nobel Prize by Evans, Capecchi and Smithies) and induced pluripotent cells iPS (Ips is a genus of insects of the order of beetles, subfamily …) (2012 Nobel Prize for Yamanaka) because they are equivalent in vitro epiblast cells. ES and iPS cells can produce any a cell individual (Wiktionary is a free open source dictionary project similar to Wikipedia (both …) and are therefore important actors for the cell therapy (In the context of biotherapies, cell therapy aims to treat cells …). Thus, understanding how these epiblast cells are produced provides advances in the knowledge and use of ES and iPS stem cells.


At three days of development in mice (or 6 in humans), the progenitor cells have a random composition of NANOG (N) and different factors (F1, F2, etc.). Only cells with the correct combination of factors (N, F1, and F2; circled in green) will differentiate at the next stage in an epiblast. Right panel: Immunostaining of a mouse embryo at three days of development with epiblast cells (red). Ladder bar: 10 microns.
© Nicolas Allègre and Claire Chazaud

To find out more:
NANOG initiates the fate of epiblast by coordinating the expression of pluripotency genes

Nicolas Allègre, Sabine Chauveau, Cynthia Dennis, Yoan Renaud, Dimitri Meistermann, Lorena Valverde Estrella, Pierre Pouchin, Michel Cohen-Tannoudji, Laurent David and Claire Chazaud.
Nature Communications June 21, 2022. https://doi.org/10.1038 / s41467-022-30858-8

Laboratories:
high school Genetics (Genetics (from the Greek genno γεννώ = to give birth) is …), reproduction and development – GReD (Inserm / CNRS / Clermont Auvergne University) – 28th place Dunant. 63000 Clermont-Ferrand.

Contact:
Claire Chazaud – Inserm Research Director – claire.chazaud at uca (Uca is a genus of crabs in the Ocypodidae family. It includes about a hundred species of …).Fr

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