Every cell must have a nucleus. But sometimes, a cell may have more nuclei. Let us know more about them.
Multinucleated cell is the term given to the cells that contain more than one nucleus in them. This means, one single cytoplasm in a cell is shared by several nucleus. Multinucleated cells maybe defined as polynuclear cells too.
Let us discuss if a cell have multiple nucleus, why they have multiple nucleus, how are they formed, what are they called and many more related questions in this article.
Can a cell have multiple nucleus?
In cytoplasm, almost all the cells in human body have only one nucleus. But in some cases, there are certain exceptions Let us see in detail.
Due to some specific conditions, few cells might have multiple nucleus in them. These types of cells are known as the multinucleated cells. Multiple nuclei help the cells to perform better in some cases.
Normal cells including liver cells, muscle fibers, and osteoclasts frequently have many nuclei. Multiple nuclei can occasionally be found in virally infected and cancerous cells.
Which cells have multiple nucleus?
Cells come in two different varieties: eukaryotic cells and prokaryotic cells. Number of nuclei in cytoplasm might vary in both types of cells. Let us know the fact in detail.
Eukaryotic cells are believed to contain several nuclei. DNA is found organized in chromosomes in the nucleus of eukaryotic cells. Prokaryotic cells are devoid of a nucleus. Their genetic material is thought to be floating in the nucleoid.
With the aid of nucleus, which contains the genetic material and is encircled by the nuclear envelope, prokaryotic cells such as bacteria and archaea are distinguished from eukaryotic cells by a distinct membrane-bound structure.
Why do some cells have multiple nucleus?
Since, nucleus contains all of the genetic information needed to produce proteins, it is typically regarded as the control centre of the cell. Let us see why some cells have multiple nucleus.
Few animal cells can be multinucleated, sometimes due to malfunction and sometimes to work better. The rate of productivity between the cells with one nucleus and the cells with multiple nuclei is greater to the latter.
How are multinucleated cells formed?
Multinucleated cells are formed when there is a fusion of monocytes or macrophages. Let us see some of the reasons behind this.
The reasons how multinucleated cells are formed are given below:
- Few cells such as the skeletal muscle cells are multinucleated cells because after the process of mitosis, cell division in them stops and the cell does not go through cytokinesis, thus producing more than one nucleus.
- During cancer or viral diseases, the cell cycle of these cells become unregulated. In these cases, these kinds of cells cannot divide properly and thus, results in having two or more nuclei in them.
- There is a case to be made for the existence of many nuclei in schizonts, that is, human liver cells which are infected with numerous rapidly multiplying malaria parasites in them.
What are multinucleated cells called?
Multinucleated cells, can be of two types that depends on the procedure by which they are formed- syncytia or coenocytes. Let us discuss more about these types in detail.
The animal cells with many nuclei are known as syncytial cells because they are multinucleated, which implies they have more than one nucleus as respect to one cell. The word “syncytia” refers to the cells formed by cell fusion. In other words, multi nuclei share a common cytoplasm in a cell.
Multinuclear cells known as syncytia can develop either naturally, as in the case of the mammalian placenta, or as a result of some disease causing species, which cause the plasma membrane to fuse. The coenocytes are the multinuclear cells that are not formed by cytokinesis but through the process of nuclear division.
Example of multinucleated cells
Below are some of the examples given for multinucleated cells:
1. Liver cells-
- Hepatocytes are cells that are found in the liver.
- They produce the proteins necessary for digestion. By the process of detoxification, they help removing toxic stuff from our body, generate enzymes that can digest fat and carbohydrates and store them in the body in the form of energy.
- The two nuclei present in liver cells are like the two blueprint sets, by which the cells can produce two proteins simultaneously.
- Thus, liver cells consist of two nuclei so that they can perform all these functions efficiently.
2. Muscles fibers-
- Muscle cells and muscle fibers contains too many nuclei in them as they are formed by the fusion of myoblasts.
- The myoblasts consist of their individual nucleus before getting fused.
- After fusion, many myoblasts come together to form the muscle fibers that contain multiple nuclei.
3. Skeletal muscle-
- The cells that make up skeletal muscles are lengthy and fibre-like. These cells combine to generate these muscles.
- As they are fused together (many combined cells) each muscle cell contains multiple nuclei.
- These muscle cells are attached to our skeleton and they help our body to move and they have multiple nuclei in them.
- Myotubes and osteoclasts are two uncommon instances of multinucleated cells observed in higher vertebrates. These cells are produced when mononucleated progenitors from the monocyte/macrophage lineage fuse.
- Human osteoclasts generally have five nuclei and their typical size range from 150 to 200 m on bone. They are big multinucleated cells that are known as osteoclasts.
- Under the control of osteoblastic cells in the bone marrow, these osteoclast precursors (OCPs) are drawn to areas on bone surfaces that are intended for resorption and merge with one another to create the multinucleated cells that resorb calcified matrixes.
5. Cancer cells-
- Cancer cells are referred to those cells that can divide continuously, this result in solid tumours or a proliferation of aberrant cells in the blood.
- In cancerous or malignant cells, there is denaturation of cell that destroys the shape, size, texture of nucleus and al the protein composition of the cell.
- Chromatin can clump together or spread out, the nucleolus can grow, and the nucleus can develop grooves, folds, or indentations.
- The cancer cells are generally formed when the genes that are taking part in regulating the process of cell division gets damaged.
- The usual equilibrium between cell growth and cell death is disrupted by variation and epimutation of the genetic information of normal cells, which results in carcinogenesis.
- As a result, the cells in the body start to divide uncontrollably.
- These uncontrolled and excessively fast growth of the cells may result in formation of the benign or malignant tumors (cancer).
Why are liver cells multinucleated?
Hepatocytes, the cells that make up our livers, are typically binucleated. The reason for the additional nucleus is connected to several tasks that the liver does. Let us discuss.
The reasons behind the liver cells being multinucleated are as follows:
- Liver does functions like detoxification of several xenobiotic compounds, produces enzymes necessary for fat, carbohydrates and proteins for digestion.
- All these functions can be possibly done while having two nuclei in a cell.
- The presence of two sets of blueprints will help direct and translate proteins more effectively for various liver activities because the nucleus contains DNA, which serves as our cells’ blueprint.
- This is because cytokinesis, or the division of the cytoplasm, did not occur during the cell cycle, leaving a cell with two nuclei.
- The reason for the additional nucleus is connected to several tasks that the liver does.
Which organism has multiple nucleus?
In some of the species, each cell contains more than one nucleus. Let us discuss more of such organisms in detail.
Fungi like coenocytic hyphae of Rhizopus and slime mould plasmodium, mammalian osteoclasts and skeletal muscle cells are examples of organisms that exhibit the multinucleate stage.
These multinucleate cells of filamentous fungi can span hundreds of meters, resulting in radically diverse microenvironments in various parts of a single cell.
Multinucleated giant cells are important mediators of tissue remodeling and repair and are also responsible for removal or sequestration of foreign material, intracellular bacteria and non-phagocytose pathogens, such as parasites and fungi.