Differentiation of cells in an embryo

In summary, embryonic cells cannot start differentiating until after the embryo is implanted in the uterus. The differentiation usually starts at the time of implantation. Blastocysts are implanted, these are already on their path of differentiation (trophoblast/inner cell mass). Embryoes likely begin differentiating with the first division.
  • #1
sontag
42
0
Can embryo cells start to differentiate before the embryo
is implanted in the uterus? The differentiation usually starts
at the time of implantation.
 
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  • #2
Blastocysts are implanted, these are already on their path of differentiation (trophoblast/inner cell mass).
 
  • #3
Embryoes likely begin differentiating with the first division. In order for areas of the body to develop in the appropriate position on the body the cells need to know their position in the body. This would most likely be accomplished by cells initially having a mechanism to turn groups of genes on or off so that they develop for the appropriate portion of the body.

Some research indicates that embryonic cells cannot each develop into all different cells. For example, an experiment to develop heart cells had to rely on watching for some of the embryonic cells in a dish to develop into cells that acted like heart cells.

http://www.washingtonpost.com/wp-dyn/articles/A52471-2004Sep26.html
 
  • #4
In vertebrates, the cells do not begin differentiating until after the 8-cell stage. Up until this point, the embryo could split in half and form twins.
 
  • #5
What stops cells differentiating in vertebrates before the 8 cell stage?
 
  • #6
VERY good question :) I'm not sure if there is a definative answer to that. Schultz et. al. (1999) proposed that a transcriptionally repressive state develops during the 2-cell stage (that transforms highly differentiated oocytes into totipotent blastomeres), where an increased histone deacetylation represses transcription.

The whole transcription machinery needs to be started again, which is sensitive to signals from the cells it is surrounded with. For me it is speculation what exactly happens at these very early stages, probably it is competition where the cells are competing against chemokines excreted by the others, when one cell takes the overhand it starts producing negative regulatory proteins that inhibit the other cells to differentiate in the same way. This then sets off a cascade that triggers the other cells to undertake other developmental routes.

You can read up on developmental biology to understand exactly how cells communicate are able to create complex architectures.
 
  • #7
nipwoni said:
In vertebrates, the cells do not begin differentiating until after the 8-cell stage. Up until this point, the embryo could split in half and form twins.

If no differentiation occurs, how do you explain conjoined twins? they develop as mirror images connected at different locations, typically the torso or head, and occasionally share organs. Something in the programming causes both to develop heads at the same end and feet at the same end, unless you know of cases in which one develops upside down compared to the other.
 
  • #8
That is the whole point: you get conjoined twins if the egg incompletely splits around the 8-cell stage (not sure exactly what the time window is).
 

Related to Differentiation of cells in an embryo

1. What is differentiation of cells in an embryo?

Differentiation is the process by which cells in an embryo become specialized and take on specific functions. This allows for the development of different tissues and organs in the body.

2. How does differentiation occur in an embryo?

Differentiation occurs through a complex process involving genetic factors, environmental cues, and cell signaling. Cells receive signals that activate specific genes, causing them to develop into different cell types.

3. What are the different types of cells that can be differentiated in an embryo?

There are three main types of cells that can be differentiated in an embryo: ectoderm, mesoderm, and endoderm. These cells give rise to different tissues and organs in the body, including the nervous system, muscles, and internal organs.

4. Can cells be re-differentiated in an embryo?

Yes, in some cases, cells can be re-differentiated. This process is known as transdifferentiation and involves changing the cell's fate to become a different cell type. However, this is a complex and rare occurrence in embryos.

5. Why is differentiation of cells in an embryo important?

Differentiation is crucial for the development of a healthy embryo and ultimately, a functioning organism. It allows for the formation of different tissues and organs, each with their specific functions, which are necessary for the proper functioning of the body.

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