Sitio CpG: Diferenzas entre revisións
Contido eliminado Contido engadido
Liña 101:
[[Ficheiro:Initiation of DNA demethylation at a CpG site.svg|miniatura|400 px|Iniciación da [[desmetilación do ADN]] nun sitio CpG. En células somáticas adultas a metilación do ADN ocorre tipicamente no contexto de dinucleótidos CpG (sitios CpG), formando [[5-metilcitosina]]-pG ou 5mCpG. As [[especie reactiva do oxíxeno|especies reactivas do oxíxeno]] poden atacar a guanina no sitio do dinucleótido, formando [[8-oxo-2'-desoxiguanosina|8-hidroxi-2'-desoxiguanosina]] (8-OHdG), orixinando nun sitio dinucleótido 5mCp-8-OHdG. O encima de [[reparación por escisión de bases]] [[oxoguanina glicosilase|OGG1]] ten como diana a 8-OHdG e únese á lesión sen escisión inmediata. A OGG1, presente no sitio 5mCp-8-OHdG recruta a [[Tet metilcitosina dioxixenase 1|TET1]] e TET1 oxida a 5mC adxacente á 8-OHdG. Isto inicia a desmetilación de 5mC.<ref name=Zhou>{{cite journal |vauthors=Zhou X, Zhuang Z, Wang W, He L, Wu H, Cao Y, Pan F, Zhao J, Hu Z, Sekhar C, Guo Z |title=OGG1 is essential in oxidative stress induced DNA demethylation |journal=Cell. Signal. |volume=28 |issue=9 |pages=1163–71 |date=September 2016 |pmid=27251462 |doi=10.1016/j.cellsig.2016.05.021 |url=}}</ref>]]
[[Ficheiro:Demethylation of 5-methylcytosine.svg|miniatura|400 px|Desmetilación de [[5-metilcitosina]] (5mC) en ADN de neuronas. Como se revisou en 2018,<ref name="pmid29875631">{{cite journal |vauthors=Bayraktar G, Kreutz MR |title=The Role of Activity-Dependent DNA Demethylation in the Adult Brain and in Neurological Disorders |journal=Front Mol Neurosci |volume=11 |issue= |pages=169 |date=2018 |pmid=29875631 |pmc=5975432 |doi=10.3389/fnmol.2018.00169 |url=}}</ref> en neuronas do cerebro, a 5mC é oxidado pola familia da translocación dez-once (TET) de dioxixenases ([[
<!--
Two reviews<ref name="pmid20649473">{{cite journal |vauthors=Massaad CA, Klann E |title=Reactive oxygen species in the regulation of synaptic plasticity and memory |journal=Antioxid. Redox Signal. |volume=14 |issue=10 |pages=2013–54 |date=May 2011 |pmid=20649473 |pmc=3078504 |doi=10.1089/ars.2010.3208 |url=}}</ref><ref name="pmid27625575">{{cite journal |vauthors=Beckhauser TF, Francis-Oliveira J, De Pasquale R |title=Reactive Oxygen Species: Physiological and Physiopathological Effects on Synaptic Plasticity |journal=J Exp Neurosci |volume=10 |issue=Suppl 1 |pages=23–48 |date=2016 |pmid=27625575 |pmc=5012454 |doi=10.4137/JEN.S39887 |url=}}</ref> summarize the large body of evidence for the critical and essential role of [[reactive oxygen species|ROS]] in [[memory]] formation. The [[DNA demethylation]] of thousands of CpG sites during memory formation depends on initiation by ROS. In 2016, Zhou et al.,<ref name=Zhou/> showed that ROS have a central role in [[DNA demethylation]].
| |||