Cure Alveolar Soft Part Sarcoma International (iCureASPS)

Induced mitotic recombination of p53 in vivo

Wei Wang, Madhuri Warren, and Allan Bradley
PNAS March 13, 2007 104 (11) 4501-4505; https://doi.org/10.1073/pnas.0607953104
Edited by Kathryn V. Anderson, Sloan–Kettering Institute, New York, NY, and approved January 18, 2007 (received for review September 12, 2006)



Abstract

Genetic mosaics produced by FLP/FRT induced mitotic recombination have been widely used in Drosophila to study gene function in development. Recently, the Cre/loxP system has been applied to induce mitotic recombination in mouse embryonic stem cells and in many adult mouse tissues. We have used this strategy to generate a previously undescribed p53 mouse model in which expression of a ubiquitously expressed recombinase in a heterozygous p53 knockout animal produces mitotic recombinant clones homozygous for the p53 mutation. The induction of loss of heterozygosity in a few cells in an otherwise normal tissue mimics genetic aspects of tumorigenesis more closely than existing models and has revealed the possible cell autonomous nature of Wnt3. Our results suggest that inducible mitotic recombination can be used for clonal analysis of mutants in the mouse.

https://www.pnas.org/content/104/11/4501

Definition of recombination
: the formation by the processes of crossing-over and independent assortment of new combinations of genes in progeny that did not occur in the parents

Meiotic versus Mitotic Recombination: Two Different Routes for Double-Strand Break Repair

Summary

Studies in the yeast Saccharomyces cerevisiae have validated the major features of the double-strand break repair (DSBR) model as an accurate representation of the pathway through which meiotic crossovers are produced. This success has led to this model being invoked to explain double-strand break (DSB) repair in other contexts. However, most non-crossover recombinants generated during S. cerevisiae meiosis do not arise via a DSBR pathway. Furthermore, and it is becoming increasing clear that DSBR is a minor pathway for recombinational repair of DSBs that occur in mitotically proliferating cells; rather, the synthesis-dependent strand annealing (SDSA) model appears to describe mitotic DSB repair more accurately. Fundamental dissimilarities between meiotic and mitotic recombination are not unexpected, since meiotic recombination serves a very different purpose (accurate chromosome segregation, which requires crossovers) than mitotic recombination (repair of DNA damage, which typically generates non-crossovers).

Keywords: meiotic recombination, mitotic recombination, double-strand break repair

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3090628/


“Cells divide and reproduce in two ways, mitosis and meiosis. Mitosis results in two identical daughter cells, whereas meiosis results in four sex cells. Below we highlight the keys differences and similarities between the two types of cell division.May 17, 2017

https://www.yourgenome.org/facts/mitosis-versus-meiosis
Mitosis versus meiosis | Facts | yourgenome.org

“Similarities

Mitosis
Diploid parent cell
Consists of interphase, prophase, metaphase, anaphase and telophase
In metaphase individual chromosomes (pairs of chromatids) line up along the equator.
During anaphase the sister chromatids are separated to opposite poles.
Ends with cytokinesis.

Meiosis
Diploid parent cell
Consists of interphase, prophase, metaphase, anaphase and telophase (but twice!)
In metaphase II individual chromosomes (pairs of chromatids) line up along the equator.
During anaphase II the sister chromatids are separated to opposite poles.
Ends with cytokinesis.”

“Differences
Mitosis
Involves one cell division?
Results in two daughter cells
Results in diploid? daughter cells? (chromosome? number remains the same as parent cell)
Daughter cells are genetically identical
Occurs in all organisms except viruses
Creates all body cells (somatic?) apart from the germ cells? (eggs and sperm)
Prophase is much shorter
No recombination/crossing over occurs in prophase.

In metaphase individual chromosomes (pairs of chromatids) line up along the equator.
During anaphase the sister chromatids are separated to opposite poles.”