Second growth phase in the eukaryotic cell cycle, prior to mitosis
Mitosis in an animal cell (phases ordered counter-clockwise), with G2 labeled at bottom.Schematic karyogram of the human chromosomes, showing their usual state in the G0 and G1 phase of the cell cycle. At top center it also shows the chromosome 3 pair after having undergone DNA synthesis, occurring in the S phase (annotated as S) of the cell cycle. This interval includes the G2 phase and metaphase (annotated as "Meta.").
Further information: Karyotype
G2 phase, Gap 2 phase, or Growth 2 phase, is the third subphase of interphase in the cell cycle directly preceding mitosis. It follows the successful completion of S phase, during which the cell’s DNA is replicated. G2 phase ends with the onset of prophase, the first phase of mitosis in which the cell’s chromatin condenses into chromosomes.
G2 phase is a period of rapid cell growth and protein synthesis during which the cell prepares itself for mitosis. Curiously, G2 phase is not a necessary part of the cell cycle, as some cell types (particularly young Xenopus embryos[1] and some cancers[2]) proceed directly from DNA replication to mitosis. Though much is known about the genetic network which regulates G2 phase and subsequent entry into mitosis, there is still much to be discovered concerning its significance and regulation, particularly in regards to cancer. One hypothesis is that the growth in G2 phase is regulated as a method of cell size control. Fission yeast (Schizosaccharomyces pombe) has been previously shown to employ such a mechanism, via Cdr2-mediated spatial regulation of Wee1 activity.[3] Though Wee1 is a fairly conserved negative regulator of mitotic entry, no general mechanism of cell size control in G2 has yet been elucidated.
Biochemically, the end of G2 phase occurs when a threshold level of active cyclin B1/CDK1 complex, also known as Maturation promoting factor (MPF) has been reached.[4] The activity of this complex is tightly regulated during G2. In particular, the G2 checkpoint arrests cells in G2 in response to DNA damage through inhibitory regulation of CDK1.
^Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2002). "An Overview of the Cell Cycle". Molecular Biology of the Cell (4th ed.). New York: Garland Science. ISBN 978-0-8153-3218-3.
^Liskay RM (April 1977). "Absence of a measurable G2 phase in two Chinese hamster cell lines". Proceedings of the National Academy of Sciences of the United States of America. 74 (4): 1622–5. Bibcode:1977PNAS...74.1622L. doi:10.1073/pnas.74.4.1622. PMC 430843. PMID 266201.)
^Moseley JB, Mayeux A, Paoletti A, Nurse P (June 2009). "A spatial gradient coordinates cell size and mitotic entry in fission yeast". Nature. 459 (7248): 857–60. Bibcode:2009Natur.459..857M. doi:10.1038/nature08074. PMID 19474789. S2CID 4330336.
^Sha W, Moore J, Chen K, Lassaletta AD, Yi CS, Tyson JJ, Sible JC (February 2003). "Hysteresis drives cell-cycle transitions in Xenopus laevis egg extracts". Proceedings of the National Academy of Sciences of the United States of America. 100 (3): 975–80. Bibcode:2003PNAS..100..975S. doi:10.1073/pnas.0235349100. PMC 298711. PMID 12509509.
G2phase, Gap 2 phase, or Growth 2 phase, is the third subphase of interphase in the cell cycle directly preceding mitosis. It follows the successful completion...
S phase (Synthesis phase) is the phase of the cell cycle in which DNA is replicated, occurring between G1 phase and G2phase. Since accurate duplication...
cycle time is spent in the G1 phase. G1 phase together with the S phase and G2phase comprise the long growth period of the cell cycle cell division called...
cell cycle is divided into four distinct phases: G1, S, G2, and M. The G phase – which is the cell growth phase – makes up approximately 95% of the cycle...
and G2phases, where the cell grows, replicates its DNA, and prepares for mitosis, respectively. Interphase was formerly called the "resting phase," but...
methionine, some cells arrest in early G1 phase. S phase follows G1 phase via the G1/S transition and precedes G2phase in interphase and is the part of the...
during the S phase. Thus, a cell grows (G1), continues to grow as it duplicates its chromosomes (S), grows more and prepares for mitosis (G2), and finally...
course with the super massive black hole at the center of the Milky Way G2phase, part of the cell cycle ATC code G02 Other gynecologicals, a subgroup of...
mitosis (the M phase) from the G2phase by phosphorylating multiple proteins needed during mitosis. MPF is activated at the end of G2 by a phosphatase...
appropriate cell size and any DNA damage . The second check point is in the G2phase, this checkpoint also checks for cell size but also the DNA replication...
The G0 phase describes a cellular state outside of the replicative cell cycle. Classically[when?], cells were thought to enter G0 primarily due to environmental...
is metabolically active and continuously grows; S phase, during which DNA replication takes place; G2, during which cell growth continues and the cell...
specific phases: S and G2phases. Since HR pathway requires sister chromatids for activation, this event only happens in the G2 and S phases of the cell...
S-phase can be referred to as "premeiotic S-phase" or "meiotic S-phase". Immediately following DNA replication, meiotic cells enter a prolonged G2-like...
and also initiates the condensation of the chromatin in the late G2phase. The G2/M phase transition is regulated by the formation of the Cdk1/cyclin B complex...
initially identified Chk1 as a serine/threonine kinase which regulates the G2/M phase transition in fission yeast. Constitutive expression of Chk1 in fission...
divide, they enter a phase called interphase. Interphase is the longest part of the cell cycle and is composed of G1, S, and G2phases. During this time...
phase, the DNA content (and thereby intensity of fluorescence) of cells in the G0 phase and G1 phase (before S), in the S phase, and in the G2phase and...
activity, which causes DNA double-strand breaks during the cell cycle G2phase, leading eventually to cell apoptosis in HeLa and Caco-2 cells. Campylobacter...
Hep G2 (or HepG2) is a human liver cancer cell line. Hep G2 is an immortal cell line which was derived in 1975 from the liver tissue of a 15-year-old...
CDT is characterized by its ability to arrest epithelial cells in the G2phase of the cell cycle and combats T cells by inducing apoptosis. Together,...
dyad. A full set of sister chromatids is created during the synthesis (S) phase of interphase, when all the chromosomes in a cell are replicated. The two...
link the inner and outer nuclear membranes.[citation needed] During the G2phase of interphase, the nuclear membrane increases its surface area and doubles...
maturation in the G2phase, centrosome separation in the mitotic phase, and centrosome disorientation in the late mitotic phase—G1 phase. Centrioles are...
undergone DNA synthesis, occurring in the S phase (annotated as S) of the cell cycle. This interval includes the G2phase and metaphase (annotated as "Meta.")...
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