Telophase In Mitosis And Meiosis (Telophase I, II)

Telophase In Mitosis And Meiosis (Telophase I, II) Overview

What is Telophase?

The telophase is both, the last phase of meiosis and the fifth phase of mitosis.

Meiosis comprises two stages: telophase I and telophase II. Separation of the duplicate genetic material, which was contained in the nucleus of the parent cells. They eventually divide into two similar daughter cells. Once the paired chromosomes have finished replicating, telophase begins as they are dragged to the opposite poles of the cell.

What happens during Telophase?

During this phase, a nuclear membrane grows around every pair of chromosomes. This process separates the cytoplasm from nuclear DNA. The chromosomes subsequently unwind, becoming less compact and more scattered. This phase is followed by cytokinesis, which divides the cytoplasm of the mother cell into two daughter cells.

Telophase in Mitosis

The mitotic cyclin-dependent kinase (CDK) substrate is dephosphorylated to initiate telophase, which is essentially an extension of anaphase and metaphase. During this stage, a number of processes contribute to the development of new daughter cells. These consist of:

The substrate of mitotic Cyclin-Dependent Kinase is dephosphorylated (Cdk)

  • Spindle assembly, chromosome condensation, and nuclear envelope collapse occur as a result of the phosphorylation of the mitotic Cyclin-dependent Kinase substrate during the early phases of mitosis.
  • While telophase, the last stage of the mitotic cell cycle, is when dephosphorylation takes place. This enables the division of new daughter cells, repair of the nuclear membrane, and disassembling the spindles.
  • The Cdc-14, one of the most important Cdks, is initially activated by being exported to the cytoplasm from the nucleolus and released into the nucleus.
  • Its primary involvement occurs in the early phases of anaphase, maintaining the mitotic spindles and allowing more Cdc-14 to enter the nucleus, where it becomes constrained.
  • Afterward, while the restriction in the nucleus plays a substantial part in the Mitotic Exit Network, the restriction in the nucleus is essential (MEN), which initiates spindle disassembly and nuclear envelope formation during telophase. The restriction in the nucleus is seen.
  • Additionally, it facilitated dephosphorylation by activating downstream regulatory proteins unique to telophase, such as CHD1 dephosphorylation proteins, which can increase cellular switching activity and eventually the G1 phase of interphase by targeting proteolysis.
  • Dephosphorylation also leads to the following:
  • Chromosome separation from the metaphase plate causes early telophase.
  • By activating ubiquitination in the proteasomes, Cdc48 also initiates the telophase procedures of spindle disassembly, nuclear envelope construction, and chromosomal condensation.

Mitotic spindle disassembly

The chromosomes are pulled to the cell poles and separated from the chromosomes due to the shrinking kinetochore microtubules.

Nuclear envelop reassembly

  • This results in the internal nuclear lamina forming into the inner nuclear membrane, the nuclear pore complexes forming, and the rebuilding of the double nuclear membrane.
  • Prophase and metaphase are the times when these organelles are broken down.
  • The endoplasmic membrane absorbs the nuclear membrane during metaphase, but during telophase, the endoplasmic reticulum targets the nuclear membrane protein-containing vesicles to the chromatin. The development of the double-layered nuclear membrane and the nuclear envelope are influenced by this.

Chromosome condensation

  • Expanded chromatin is created by chromosome condensation (or decompaction). The preparation of the cell and the beginning of the interphase rely on compact chromosomes.
  • Condensation occurs simultaneously with the development of the nuclear envelope, which is mediated by the dephosphorylation of Cyclin-Dependent Kinase in the Mitotic-Exit Network (MEN), which restarts interphase.

Telophase in mitosis: Summary

  • The last stage of mitosis is known as telophase.
  • Creating a new nuclear membrane, unfolding chromosomes into chromatins, the reappearance of cell nucleoli, and resumption of cell growth all occur simultaneously. This is the reverse of what occurred during anaphase and metaphase.
  • In this phase, the sister chromatids approach the opposite poles of the cell.
  • During the completion of the cell cycle, the nuclear vesicles assemble around the chromosomes.
  • In one of the new cells, the nuclear membrane reforms by joining with the chromosomes to create two nuclei.
  • In this phase, the polar microtubules keep growing while the kinetochore microtubules are also disintegrated.
  • While the nuclear membrane underwent reformation, the chromosomes started to shrink and disperse.

Telophase in Meiosis

Telophase I

  • During telophase I, homologous chromosomes split into separate nuclei.
  • The cell restores its nuclear membrane, deconstructs the microtubules and spindle fibers, and then initiates cytokinesis.
  • The cell then moves into the interkinesis period of rest.

Telophase II

  • At this stage, the sister chromatids of every chromosome are completely separate, and a fresh nuclear membrane is forming around them.
  • Although the concept is that the cells exchange the identical chromosome, differentiation happens at recombination, which involves a partial exchange of homologous chromosomes during prophase 1.
  • By the time meiosis is complete, there are two alleles for each gene present in each of the four cells, which are then split up in various ways and combined with alleles from other genes.

Reference and Source

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