CAF-1
CAF-1 (chromatin assembly factor-1) is a complex, including Chaf1a (p150), Chaf1b (p60) and p50 subunits that assembles histone tetramers onto replicating DNA in vitro[1][2][3] This complex is histone chaperone involved in creating cellular memory of somatic cell identity - cellular differentiation.
CAF-1 is required for the spatial organization and epigenetic marking of heterochromatin domains in pluripotent embryonic cells.[4]
Cells resembling 2-cell-stage mouse embryos (totipotent cells) can be induced in vitro through downregulation of the chromatin-assembly activity of CAF-1 in embryonic stem cells.[5]
Optimal modulation of both CAF-1 and transcription factor levels increases reprogramming efficiency by several orders of magnitude and facilitated iPS cell formation in as little as 4 days. Mechanistically, CAF-1 suppression led to a more accessible chromatin structure at enhancer elements early during reprogramming. These changes were accompanied by a decrease in somatic heterochromatin domains, increased binding of Sox2 to pluripotency-specific targets and activation of associated genes. Suppression of CAF-1 also enhance the direct conversion of B cells into macrophages and fibroblasts into neurons..[6]
References
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Smith, S., & Stillman, B. (1989). Purification and characterization of CAF-I, a human cell factor required for chromatin assembly during DNA replication in vitro. Cell, 58(1), 15-25.DOI: http://dx.doi.org/10.1016/0092-8674(89)90398-X
- ↑ Hoek, M. & Stillman, B. (2003). Chromatin assembly factor 1 is essential and couples chromatin assembly to DNA replication in vivo. Proc. Natl Acad. Sci. USA 100, 12183–12188
- ↑ Houlard M, Berlivet S, Probst AV, Quivy J-P, Héry P, Almouzni G, et al. (2006). CAF-1 Is Essential for Heterochromatin Organization in Pluripotent Embryonic Cells. PLoS Genet 2(11): e181. doi:10.1371/journal.pgen.0020181
- ↑ Ishiuchi, T., Enriquez-Gasca, R., Mizutani, E., Bošković, A., Ziegler-Birling, C., Rodriguez-Terrones, D., ... & Torres-Padilla, M. E. (2015). Early embryonic-like cells are induced by downregulating replication-dependent chromatin assembly. Nature Structural & Molecular Biology 22, 662–671 doi:10.1038/nsmb.3066
- ↑ Cheloufi S., Elling U., Hopfgartner B. et al., & Zuber J., Hochedlinger K. (2015). The histone chaperone CAF-1 safeguards somatic cell identity. Nature 528, 218–224 doi:10.1038/nature15749
Further reading
- Memory loss enables the production of stem cells. ScienceDaily
- Yu, Z., Liu, J., Deng, W. M., & Jiao, R. (2015). Histone chaperone CAF-1: essential roles in multi-cellular organism development. Cellular and Molecular Life Sciences, 72(2), 327-337. doi:10.1007/s00018-014-1748-3
- Kaufman, P. D. (2015). Want reprogramming? Cut back on the chromatin assembly!. Nature structural & molecular biology, 22(9), 648-650. doi:10.1038/nsmb.3081
- Polo, S. E., & Almouzni, G. (2015). Chromatin dynamics after DNA damage: The legacy of the access–repair–restore model. DNA repair. 36, 114–121 doi:10.1016/j.dnarep.2015.09.014
