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What is Undifferentiated Cell?

Meaning of Undifferentiated Cell

The undifferentiated cell consists of a cell that does not yet have a biological function, since it does not yet express the characteristic proteins of a tissue. Cells with less differentiation, that is, with less gene expression, are present in the embryo.

However, in the regeneration lines of some tissues, such as blood tissue, there are cells with small degrees of differentiation, but larger than the embryonic ones, which are renewed at all times.

The functions that cells can perform in an organism are determined during the process of cell differentiation, that is, an undifferentiated cell is one that has not yet shown phenotypic characteristics of a specific cell type, so it has great potential to originate any cell type. body, provided that it receives the chemical stimulus for the production of specific proteins.

Undifferentiated cells are also called stem cells.

The term “stem cell” refers to precursor cells that have the capacity for unlimited differentiation and self-renewal, and can give rise to a variety of tissue types. In addition, stem cells can be programmed to carry out specific functions since they do not have a specialization.

What makes one cell different from another in the same organism?

All the cells of an individual have the same genetic material, called the genome, and in that material is found the code to produce the complete characteristics of the whole organism.

When cells have not yet differentiated into a specific type, it is because they have not yet expressed most of the genes for the proteins characteristic of their lineage.

But when they start the cell differentiation process, some genes will be expressed and others will be silenced. Thus, it is possible to produce differential characteristics in each tissue of the body.

Example

See the following example: the genes for the production of the protein keratin are present in the genome of all cells in the body, however its production will not occur in blood cells, liver (hepatocytes) or even cells of the intestine (enterocytes), for example.

But, in the epidermis, this protein will be produced through the expression of these genes, causing protection and waterproofing of this tissue.

This production of proteins or differential activation of genes in the different tissues of the organism is stimulated by growth factors, produced in the embryo and in adult tissues. Such factors are responsible for “turning on” or silencing genes and are characteristic of each cell line.

Undifferentiated Cells vs Stem Cells

Stem cells are classified as totipotent, pluripotent, multipotent, and unipotent, considering the difference between their levels of plasticity, how many different pathways they can follow, and what tissue they can contribute to.

However, totipotent stem cells are the most undifferentiated cells, so they give rise to the embryo and can differentiate into any cell in the body. They correspond to the zygote until the end of the morula.

They have the potential to give rise to both the cells of the embryo and those of the extraembryonic valve, which will form the placenta and other junctions. However, these cells are transient and disappear a few days after fertilization.

Successively, the pluripotent stem cells form the embryoblast into the blastocyst.

They give rise to the cells of the embryo, but are not capable of giving rise to embryonic junctions. The multipotent ones constitute the three germinal leaflets (ectoderm, mesoderm and endoderm), which, each one of them already has a phenotypic determination that will originate a group of own tissues and organs, for example, the ectoderm will form the skin, the nervous system, the mesoderm, the musculoskeletal system and endoderm, the digestive and respiratory organs.

Finally, the unipotent cells form the group for the development of specific tissues, such as blood stem cells from the bone marrow, which will give rise to myeloid and lymphoid stem cells and their derivatives, and those responsible for tissue renewal, such as cells of the basal layer of the epidermis.

Thus, it is possible to consider the ovule or zygote and the cells of the morula stage, the first cells of an embryo, as completely undifferentiated cells, since they do not yet express any specific protein of any tissue.

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