{"id":5295,"date":"2017-10-21T10:23:12","date_gmt":"2017-10-21T08:23:12","guid":{"rendered":"https:\/\/ellipse.prbb.org\/?p=5295"},"modified":"2024-06-03T12:44:46","modified_gmt":"2024-06-03T10:44:46","slug":"de-gens-proteines-i-arn-no-codificants","status":"publish","type":"post","link":"https:\/\/ellipse.prbb.org\/ca\/de-gens-proteines-i-arn-no-codificants\/","title":{"rendered":"De gens, prote\u00efnes i ARN no codificants"},"content":{"rendered":"<p>L\u2019<strong>ADN <\/strong>es podria definir com el <strong>manual d\u2019instruccions<\/strong> per a la vida. Especifica les ordres per fabricar les prote\u00efnes, els \u201cblocs\u201d de construcci\u00f3 dels \u00e9ssers vius. Quan diem que un gen s\u2019expressa, vol dir que un tros d\u2019ADN es \u201ctradueix\u201d en una mol\u00e8cula d\u2019<strong>ARN<\/strong> \u2014en un proc\u00e9s anomenat \u201c<strong>traducci\u00f3<\/strong>\u201d\u2014, que al seu torn es \u201ctranscriu\u201d en una prote\u00efna \u2014en un proc\u00e9s anomenat \u201c<strong>transcripci\u00f3<\/strong>\u201d. Aquest va ser durant d\u00e8cades el dogma de la biologia molecular: cada gen codifica per a una prote\u00efna.<\/p>\n<p>&nbsp;<\/p>\n<blockquote><p>El dogma de la biologia molecular: l&#8217;<strong>ADN<\/strong> (els gens) es transcriu a l&#8217;<strong>ARN<\/strong>, i aquest es tradueix per donar lloc a una <strong>prote\u00efna<\/strong>.<\/p><\/blockquote>\n<p>&nbsp;<\/p>\n<p>Ja fa anys, per\u00f2, que es va descobrir l\u2019exist\u00e8ncia de l\u2019<a href=\"https:\/\/ellipse.prbb.org\/ca\/lsplicing-o-empalmament\/\" target=\"_blank\" rel=\"noopener noreferrer\"><em>splicing<\/em> (o empalmament) alternatiu<\/a>, un proc\u00e9s que \u201ctalla i enganxa\u201d trossos d\u2019ARN de diferents maneres, fent que un sol ARN pugui donar lloc a diferents prote\u00efnes.<\/p>\n<p>En els darrers temps, un altre fenomen ha alterat de nou el dogma. Ara sabem que hi ha milers de <strong>fragments d\u2019ARN que no donen lloc a cap prote\u00efna<\/strong>. S\u00f3n els anomenats \u201c<strong>ARN no codificants<\/strong>\u201d (ARNnc), i n\u2019hi ha de molts tipus. Ja entre els anys 60 i 80 es van descobrir els ARN de transfer\u00e8ncia (<strong>ARNt<\/strong>) i els ribosomals (<strong>ARNr<\/strong>); per\u00f2 ha estat la darrera d\u00e8cada la que ha vist un augment exponencial d\u2019aquests ARNnc, que s\u2019han anat classificant segons les seves caracter\u00edstiques en diferents tipus: <strong>microARNs, siARNs, piARNs, snoARNs, snARN, exARNs, scaARNs<\/strong>, etc.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_5276\" aria-describedby=\"caption-attachment-5276\" style=\"width: 847px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-5276 size-large\" src=\"https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2017\/10\/dna-rna-847x600.png\" alt=\"Els gens es transcriuen a un intermediari mRNA, que despr\u00e9s es tradueix a una prote\u00efna funcional. Els gens d'ARN, per\u00f2, es transcriuen a un ARN no codificant funcional. \" width=\"847\" height=\"600\" srcset=\"https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2017\/10\/dna-rna-847x600.png 847w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2017\/10\/dna-rna-316x224.png 316w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2017\/10\/dna-rna-768x544.png 768w, https:\/\/ellipse.prbb.org\/wp-content\/uploads\/2017\/10\/dna-rna.png 1228w\" sizes=\"auto, (max-width: 847px) 100vw, 847px\" \/><figcaption id=\"caption-attachment-5276\" class=\"wp-caption-text\">Els gens es transcriuen a un intermediari mRNA, que despr\u00e9s es tradueix a una prote\u00efna funcional. Els gens d&#8217;ARN, per\u00f2, es transcriuen a un ARN no codificant funcional. Imatge de Thomas Shafee. CC BY 4.0<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<blockquote><p>Ara sabem que hi ha milers de fragments d\u2019ARN que no donen lloc a cap prote\u00efna; s\u00f3n els \u201c<strong>ARN no codificants<\/strong>\u201d (ARNnc).<\/p><\/blockquote>\n<p>&nbsp;<\/p>\n<p>Tot i que les funcions d\u2019aquests ARNnc no estan del tot clares \u2014i alguns d\u2019ells pot ser que ni tan sols tinguin una funci\u00f3, sin\u00f3 que siguin conseq\u00fc\u00e8ncia d\u2019una traducci\u00f3 aleat\u00f2ria de l\u2019ADN\u2014, molts d\u2019ells estan <strong>conservats<\/strong> en totes les esp\u00e8cies i han estat implicats en molts processos cel\u00b7lulars importants, com la <strong>regulaci\u00f3<\/strong> de l\u2019<strong>expressi\u00f3 g\u00e8nica<\/strong>, aix\u00ed com en diverses malalties, com el <strong>c\u00e0ncer<\/strong>, l\u2019<strong>autisme<\/strong> i l\u2019<strong>Alzheimer<\/strong>.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>El dogma central de la biologia diu que l&#8217;ADN es tradueix en ARN, que despr\u00e9s es transcriu en prote\u00efnes. Per\u00f2 la realitat ens mostra una altra cosa&#8230; us presentem els ARN no codificants.<\/p>\n","protected":false},"author":6,"featured_media":5291,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[30],"tags":[275,320,555,297,312,513,332,329],"new-type":[35],"class_list":["post-5295","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ciencia-i-societat","tag-adn","tag-alzheimer","tag-arn","tag-biologia-molecular","tag-cancer-ca","tag-ciencia-al-descobert","tag-gens","tag-proteines","new-type-noticies"],"acf":[],"_links":{"self":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/5295","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/comments?post=5295"}],"version-history":[{"count":3,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/5295\/revisions"}],"predecessor-version":[{"id":42924,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/posts\/5295\/revisions\/42924"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/media\/5291"}],"wp:attachment":[{"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/media?parent=5295"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/categories?post=5295"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/tags?post=5295"},{"taxonomy":"new-type","embeddable":true,"href":"https:\/\/ellipse.prbb.org\/ca\/wp-json\/wp\/v2\/new-type?post=5295"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}