User:Madeleine Wilson/Sandbox 1: Difference between revisions

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[https://en.wikipedia.org/wiki/Histone Histone proteins] aid in the packing of DNA for the purpose of compacting the genome in the nucleus of the cell and regulating physical accessibility of genes for transcription. The protein itself is an octamer of core proteins H2a, H2b, H3, and H4, which organize into two heterodimers; H1 and H5 act as linker proteins. About 145-157 base pairs wind around a histone heterodimer core. <ref name="DesJarlais">PMID: 26745824</ref> Modifications to histone core proteins can affect the accessibility of transcription factors in the genome, either promoting or inhibiting transcription. Some of these modifications include methylation/demethylation, acetylation/deacetylation, and ubiquitination/deubiquitination. <ref name="Lun">DOI: 10.1016/j.apsb.2013.04.007</ref>
[https://en.wikipedia.org/wiki/Histone Histone proteins] aid in the packing of DNA for the purpose of compacting the genome in the nucleus of the cell and regulating physical accessibility of genes for transcription. The protein itself is an octamer of core proteins H2a, H2b, H3, and H4, which organize into two heterodimers; H1 and H5 act as linker proteins. About 145-157 base pairs wind around a histone heterodimer core. <ref name="DesJarlais">PMID: 26745824</ref> Modifications to histone core proteins can affect the accessibility of transcription factors in the genome, either promoting or inhibiting transcription. Some of these modifications include methylation/demethylation, acetylation/deacetylation, and ubiquitination/deubiquitination. <ref name="Lun">DOI: 10.1016/j.apsb.2013.04.007</ref>


Specifically, histone methylation is associated with gene activation. <ref name="Dong">PMID: 23566087</ref> Many domain families fall under the histone methylase family, one of these enzymes being the <scene name='81/811092/Set7_domain/1'>SET7 domain</scene> family, which can target H3, H4, or H2a. Sites known for gene activation are Lysine-4, Lys-36, and Lys-79 on H3; whereas, methylation at Lys-9 and Lys- 27 on H3 and Lys-20 on H4 are known for gene inactivation.<ref name="Rizzo">PMID: 21847010</ref> Typically, methylation of some of these sites are always present on both active and inactive genes, extra methylations required for activity; specifics of this characteristic depend on site and species of organism. <ref name="Xiao">doi:10.1038/nature01378</ref> Some tumor related genes such as p53 are site specifically methylated to promote biological function <ref name = "Rizzo" />, whereas hypomethylation of CpG is linked to tumor genesis. <ref name="Lun" /> A particular enzyme in the SET7 domain family is lysine methyltransferase, which acts on the histone by adding a methyl group to Lys4 on H3; the addition results in promotion of gene unwinding and gene transcription. <ref name="Xiao" />, <ref name="Dong" />
Specifically, histone methylation is associated with gene activation. <ref name="Dong">PMID: 23566087</ref> Many domain families fall under the histone methylase family, one of these enzymes being the <scene name='81/811092/Set7_domain/2'>SET7 domain</scene> family, which can target H3, H4, or H2a. Sites known for gene activation are Lysine-4, Lys-36, and Lys-79 on H3; whereas, methylation at Lys-9 and Lys- 27 on H3 and Lys-20 on H4 are known for gene inactivation.<ref name="Rizzo">PMID: 21847010</ref> Typically, methylation of some of these sites are always present on both active and inactive genes, extra methylations required for activity; specifics of this characteristic depend on site and species of organism. <ref name="Xiao">doi:10.1038/nature01378</ref> Some tumor related genes such as p53 are site specifically methylated to promote biological function <ref name = "Rizzo" />, whereas hypomethylation of CpG is linked to tumor genesis. <ref name="Lun" /> A particular enzyme in the SET7 domain family is lysine methyltransferase, which acts on the histone by adding a methyl group to Lys4 on H3; the addition results in promotion of gene unwinding and gene transcription. <ref name="Xiao" />, <ref name="Dong" />


==Lysine Methyltransferase (KMT) Structure==
==Lysine Methyltransferase (KMT) Structure==
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