endomitotic cell cycle

Definition

Target type: biologicalprocess

A mitotic cell cycle in which chromosomes are replicated and sister chromatids separate, but spindle formation, nuclear membrane breakdown and nuclear division do not occur, resulting in an increased number of chromosomes in the cell. [GOC:curators, GOC:dos, GOC:expert_vm]

Endomitosis, also known as endoreplication, is a specialized form of cell cycle where the cell undergoes repeated rounds of DNA replication without subsequent nuclear division. This results in polyploidy, a condition where the cell possesses multiple copies of its genome. In contrast to mitosis, where the duplicated chromosomes are segregated into two daughter cells, endomitosis involves a single nucleus that continues to accumulate replicated DNA.

The process of endomitosis is driven by specific regulatory mechanisms that differ from those controlling typical mitosis. The cell cycle checkpoints, which normally ensure accurate DNA replication and chromosome segregation, are bypassed in endomitosis. This allows the cell to continue replicating its DNA without proceeding through the mitotic phases.

Endomitosis is a common phenomenon in various biological systems, including plants, animals, and fungi. It plays crucial roles in several developmental and physiological processes:

1. **Cell Growth and Differentiation:** In many tissues, endomitosis contributes to increased cell size and specialized functions. For example, in plants, endoreplication is essential for the development of large, polyploid cells in tissues such as leaves and roots.

2. **Metabolic Processes:** Endomitosis can enhance metabolic activity by increasing the number of genes and proteins involved in specific pathways. For instance, in the liver, endomitosis contributes to the production of enzymes involved in detoxification and drug metabolism.

3. **Stress Response:** Endomitosis can be induced by various environmental stresses, such as nutrient deprivation or hypoxia. In these situations, the cell may undergo endomitosis to increase its metabolic capacity or to enhance its survival under adverse conditions.

4. **Developmental Plasticity:** Endomitosis provides a mechanism for generating cellular diversity and adaptability. By varying the degree of polyploidy, cells can acquire distinct properties and contribute to the formation of specialized tissues.

Endomitosis is a fascinating and complex process that exemplifies the plasticity of the cell cycle. By bypassing the typical mitotic phases, endomitosis allows cells to accumulate multiple copies of their genome, leading to various functional and developmental consequences.'
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Proteins (2)

Compounds (94)