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Maturation-promoting factor (abbreviated MPF, also called mitosis-promoting factor or M-Phase-promoting factor) is the cyclin–Cdk complex that was discovered first in frog eggs. [1] [2] It stimulates the mitotic and meiotic phases of the cell cycle.
Cells with a defective G 2-M checkpoint will undergo apoptosis or death after cell division if they enter the M phase before repairing their DNA. [1] The defining biochemical feature of this checkpoint is the activation of M-phase cyclin-CDK complexes, which phosphorylate proteins that promote spindle assembly and bring the cell to metaphase. [2]
A promoter is induced in response to changes in abundance or conformation of regulatory proteins in a cell, which enable activating transcription factors to recruit RNA polymerase. [4] [5] Given the short sequences of most promoter elements, promoters can rapidly evolve from random sequences.
The cell cycle is a series of complex, ordered, sequential events that control how a single cell divides into two cells, and involves several different phases. The phases include the G1 and G2 phases, DNA replication or S phase, and the actual process of cell division, mitosis or M phase. [1]
Promoters in eukaryotes contain one or more of these core promotes elements (but any of them are absolutely essential for promoter function), [9] these elements are binding sites for subunits of the transcriptional machinery and are involve in the initiation of the transcription, but also they have some specific enhancer functions. [10] In ...
At the end of G2, the cell transitions into mitosis, where the nucleus divides. The G2 to M transition is dramatic; there is an all-or-nothing effect, and the transition is irreversible. This is advantageous to the cell because entering mitosis is a critical step in the life cycle of a cell.
Three types of cell division: binary fission (taking place in prokaryotes), mitosis and meiosis (taking place in eukaryotes).. When cells are ready to divide, because cell size is big enough or because they receive the appropriate stimulus, [20] they activate the mechanism to enter into the cell cycle, and they duplicate most organelles during S (synthesis) phase, including their centrosome.
These regions often correspond to promoter regions of genes that were active in that cell type prior to chromatin formation. The lack of compaction of these regions is called bookmarking , which is an epigenetic mechanism believed to be important for transmitting to daughter cells the "memory" of which genes were active prior to entry into ...