{"id":1862,"date":"2024-03-03T16:14:17","date_gmt":"2024-03-03T16:14:17","guid":{"rendered":"https:\/\/cake.appscodestudio.com\/?p=1862"},"modified":"2024-03-03T17:20:09","modified_gmt":"2024-03-03T17:20:09","slug":"methylation","status":"publish","type":"post","link":"https:\/\/cake.appscodestudio.com\/index.php\/2024\/03\/03\/methylation\/","title":{"rendered":"Methylation"},"content":{"rendered":"\n<p>Three types of natural methylation have been reported in&nbsp;DNA. Cytosine can be modified either on the ring to form 5-methylcytosine or on the exocyclic amino group to form N<sup>4<\/sup>-methylcytosine. Adenine may be modified to form N<sup>6<\/sup>-methyladenine. N<sup>4<\/sup>-methylcytosine and N<sup>6<\/sup>-methyladenine are found only in&nbsp;bacteria&nbsp;and&nbsp;archaea, whereas 5-methylcytosine is widely distributed. Special enzymes called DNA methyltransferases are responsible for this methylation; they recognize specific sequences within the DNA&nbsp;molecule&nbsp;so that only a subset of the bases is modified. Other methylations of the bases or of the&nbsp;deoxyribose&nbsp;are sometimes&nbsp;induced by carcinogens. These usually lead to mispairing of the bases during replication and have to be removed if they are not to become mutagenic.<\/p>\n\n\n\n<p>Natural methylation has many cellular functions. In bacteria and archaea, methylation forms an essential part of the&nbsp;immune system&nbsp;by protecting DNA molecules from fragmentation by&nbsp;restriction endonucleases. In some organisms, methylation helps to eliminate incorrect base sequences introduced during DNA replication. By marking the parental strand with a&nbsp;methyl group, a cellular mechanism known as the mismatch repair system distinguishes between the newly replicated strand where the errors occur and the correct sequence on the template strand. In higher eukaryotes, 5-methylcytosine controls many cellular phenomena by preventing DNA transcription. Methylation is also believed to signal imprinting, a process whereby some genes inherited from one parent are selectively inactivated. Correct methylation may also repress or activate key genes that control embryonic development. On the other hand, 5-methylcytosine is potentially mutagenic because&nbsp;thymine&nbsp;produced during the methylation process converts C:G pairs to T:A pairs. In mammals, methylation takes place selectively within the dinucleotide sequence CG\u2014a rare sequence, presumably because it has been lost by mutation. In many cancers, mutations are found in key genes at&nbsp;CG dinucleotides.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Three types of natural methylation have been reported in&nbsp;DNA. Cytosine can be modified either on the ring to form 5-methylcytosine or on the exocyclic amino group to form N4-methylcytosine. Adenine may be modified to form N6-methyladenine. N4-methylcytosine and N6-methyladenine are found only in&nbsp;bacteria&nbsp;and&nbsp;archaea, whereas 5-methylcytosine is widely distributed. Special enzymes called DNA methyltransferases are responsible [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-1862","post","type-post","status-publish","format-standard","hentry","category-nucleic-acids"],"Cooking_time":"","jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1862","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/comments?post=1862"}],"version-history":[{"count":2,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1862\/revisions"}],"predecessor-version":[{"id":1940,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1862\/revisions\/1940"}],"wp:attachment":[{"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/media?parent=1862"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/categories?post=1862"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cake.appscodestudio.com\/index.php\/wp-json\/wp\/v2\/tags?post=1862"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}