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Replication stress and its consequences in mitosis. DNA replication stress refers to the state of a cell whose genome is exposed to various stresses. The events that contribute to replication stress occur during DNA replication, and can result in a stalled replication fork. [1] There are many events that contribute to replication stress ...
Steps of the cell cycle. The G 2-M checkpoint occurs between the G 2 and M phases. G2-M arrest. The G 2-M DNA damage checkpoint is an important cell cycle checkpoint in eukaryotic organisms that ensures that cells don't initiate mitosis until damaged or incompletely replicated DNA is sufficiently repaired.
Similar to S Phase, G2 experiences a DNA damage checkpoint. The cell is once more examined for sites of DNA damage or incomplete replication, and the kinases ATR and ATM are recruited to damage sites. Activation of Chk1 and Chk2 also transpire, as well as p53 activation, to induce cell cycle arrest and halt progression into mitosis.
Chk1 is essential for the maintenance of genomic integrity. Chk1 monitors DNA replication in unperturbed cell cycles and responds to genotoxic stress if present. [9] Chk1 recognizes DNA strand instability during replication and can stall DNA replication in order to allow time for DNA repair mechanisms to restore the genome. [8] Recently, Chk1 ...
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
The mitosis process in the cells of eukaryotic organisms follows a similar pattern, but with variations in three main details. "Closed" and "open" mitosis can be distinguished on the basis of nuclear envelope remaining intact or breaking down. An intermediate form with partial degradation of the nuclear envelope is called "semiopen" mitosis.
Interphase is the process through which a cell must go before mitosis, meiosis, and cytokinesis. [15] Interphase consists of three main phases: G 1, S, and G 2. G 1 is a time of growth for the cell where specialized cellular functions occur in order to prepare the cell for DNA replication. [16]
Chk1 signaling is vital for arresting the cell cycle and preventing cells from entering mitosis with incomplete DNA replication or DNA damage. The Chk1-dependent Cdk inhibition is important for the function of the ATR-Chk1 checkpoint and to arrest the cell cycle and allow sufficient time for completion of DNA repair mechanisms, which in turn ...