{"id":3292,"date":"2016-12-12T23:41:45","date_gmt":"2016-12-12T23:41:45","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology1\/?post_type=chapter&#038;p=3292"},"modified":"2024-04-26T00:24:42","modified_gmt":"2024-04-26T00:24:42","slug":"reading-eukaryotic-transcription-gene-regulation","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/chapter\/reading-eukaryotic-transcription-gene-regulation\/","title":{"raw":"Eukaryotic Transcription Gene Regulation","rendered":"Eukaryotic Transcription Gene Regulation"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Discuss the role of transcription factors in gene regulation<\/li>\r\n<\/ul>\r\n<\/div>\r\nLike prokaryotic cells, the transcription of genes in eukaryotes requires the actions of an RNA polymerase to bind to a sequence upstream of a gene to initiate transcription. However, unlike prokaryotic cells, the eukaryotic RNA polymerase requires other proteins, or transcription factors, to facilitate transcription initiation. <strong>Transcription factors<\/strong> are proteins that bind to the <strong>promoter<\/strong> sequence and other regulatory sequences to control the transcription of the target gene. RNA polymerase by itself cannot initiate transcription in eukaryotic cells. Transcription factors must bind to the promoter region first and recruit RNA polymerase to the site for transcription to be established.\r\n<div class=\"textbox shaded\">\r\n\r\nView the process of transcription\u2014the making of RNA from a DNA template:\r\n\r\nhttps:\/\/youtu.be\/WsofH466lqk\r\n\r\n<\/div>\r\n<h2>The Promoter and the Transcription Machinery<\/h2>\r\n[caption id=\"attachment_3898\" align=\"alignright\" width=\"345\"]<img class=\" wp-image-3898\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1087\/2016\/12\/12233554\/Figure_16_04_01.jpg\" alt=\"Eukaryotic gene expression is controlled by a promoter immediately adjacent to the gene, and an enhancer far upstream. The DNA folds over itself, bringing the enhancer next to the promoter. Transcription factors and mediator proteins are sandwiched between the promoter and the enhancer. Short DNA sequences within the enhancer called distal control elements bind activators, which in turn bind transcription factors and mediator proteins bound to the promoter. RNA polymerase binds the complex, allowing transcription to begin. Different genes have enhancers with different distal control elements, allowing differential regulation of transcription.\" width=\"345\" height=\"404\" \/> Figure 1. An enhancer is a DNA sequence that promotes transcription. Each enhancer is made up of short DNA sequences called distal control elements. Activators bound to the distal control elements interact with mediator proteins and transcription factors. Two different genes may have the same promoter but different distal control elements, enabling differential gene expression.[\/caption]\r\n\r\nGenes are organized to make the control of gene expression easier. The <strong>promoter region<\/strong> is immediately upstream of the coding sequence. The purpose of the promoter is to bind transcription factors that control the initiation of transcription.\r\n<h2>Enhancers and Transcription<\/h2>\r\nIn some eukaryotic genes, there are regions that help increase or enhance transcription. These regions, called <strong>enhancers<\/strong>, are not necessarily close to the genes they enhance. They can be located upstream of a gene, within the coding region of the gene, downstream of a gene, or may be thousands of nucleotides away.\u00a0 Enhancer regions are binding sequences, or sites, for transcription factors. When a DNA-bending protein binds, the shape of the DNA changes (Figure 1). This shape change allows for the interaction of the <strong>activators<\/strong> bound to the enhancers with the transcription factors bound to the promoter region and the RNA polymerase.\r\n<h2>Turning Genes Off: Transcriptional Repressors<\/h2>\r\nLike prokaryotic cells, eukaryotic cells also have mechanisms to prevent transcription. Transcriptional <strong>repressors<\/strong> can bind to promoter or enhancer regions and block transcription. Like the transcriptional activators, repressors respond to external stimuli to prevent the binding of activating transcription factors.\r\n<div class=\"textbox learning-objectives\">\r\n<h3>In Summary: Eukaryotic Transcription Gene Regulation<\/h3>\r\nTo start transcription, transcription factors,\u00a0 must first bind to the promoter and recruit RNA polymerase to that location. \u00a0 In addition to promoter sequences, enhancer regions help augment transcription. Enhancers can be upstream, downstream, within a gene itself, or on other chromosomes. Transcription factors bind to enhancer regions to increase or prevent transcription.\r\n\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Questions<\/h3>\r\nThe binding of ________ is required for transcription to start.\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>a protein<\/li>\r\n \t<li>DNA polymerase<\/li>\r\n \t<li>RNA polymerase<\/li>\r\n \t<li>a transcription factor<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"670222\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"670222\"]Answer c.\u00a0The binding of RNA polymerase is required for transcription to start.\r\n\r\n[\/hidden-answer]\r\n\r\nWhat will result from the binding of a transcription factor to an enhancer region?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>decreased transcription of an adjacent gene<\/li>\r\n \t<li>increased transcription of a distant gene<\/li>\r\n \t<li>alteration of the translation of an adjacent gene<\/li>\r\n \t<li>initiation of the recruitment of RNA polymerase<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"829037\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"829037\"]Answer b. Increased transcription of a distant gene\u00a0will result from the binding of a transcription factor to an enhancer region.\r\n\r\n[\/hidden-answer]\r\n\r\nA mutation within the promoter region can alter transcription of a gene. Describe how this can happen.\r\n\r\n[practice-area rows=\"2\"][\/practice-area]\r\n[reveal-answer q=\"332179\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"332179\"]A mutation in the promoter region can change the binding site for a transcription factor that normally binds to increase transcription. The mutation could either decrease the ability of the transcription factor to bind, thereby decreasing transcription, or it can increase the ability of the transcription factor to bind, thus increasing transcription.\r\n\r\n[\/hidden-answer]\r\n\r\nWhat could happen if a cell had too much of an activating transcription factor present?\r\n\r\n[practice-area rows=\"2\"][\/practice-area]\r\n[reveal-answer q=\"162780\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"162780\"]If too much of an activating transcription factor were present, then transcription would be increased in the cell. This could lead to dramatic alterations in cell function. \u00a0[\/hidden-answer]\r\n\r\n<\/div>\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/ddc36758-3e88-4fd6-ad2c-a74640bdbb59\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Discuss the role of transcription factors in gene regulation<\/li>\n<\/ul>\n<\/div>\n<p>Like prokaryotic cells, the transcription of genes in eukaryotes requires the actions of an RNA polymerase to bind to a sequence upstream of a gene to initiate transcription. However, unlike prokaryotic cells, the eukaryotic RNA polymerase requires other proteins, or transcription factors, to facilitate transcription initiation. <strong>Transcription factors<\/strong> are proteins that bind to the <strong>promoter<\/strong> sequence and other regulatory sequences to control the transcription of the target gene. RNA polymerase by itself cannot initiate transcription in eukaryotic cells. Transcription factors must bind to the promoter region first and recruit RNA polymerase to the site for transcription to be established.<\/p>\n<div class=\"textbox shaded\">\n<p>View the process of transcription\u2014the making of RNA from a DNA template:<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Transcription\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/WsofH466lqk?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<\/div>\n<h2>The Promoter and the Transcription Machinery<\/h2>\n<div id=\"attachment_3898\" style=\"width: 355px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-3898\" class=\"wp-image-3898\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1087\/2016\/12\/12233554\/Figure_16_04_01.jpg\" alt=\"Eukaryotic gene expression is controlled by a promoter immediately adjacent to the gene, and an enhancer far upstream. The DNA folds over itself, bringing the enhancer next to the promoter. Transcription factors and mediator proteins are sandwiched between the promoter and the enhancer. Short DNA sequences within the enhancer called distal control elements bind activators, which in turn bind transcription factors and mediator proteins bound to the promoter. RNA polymerase binds the complex, allowing transcription to begin. Different genes have enhancers with different distal control elements, allowing differential regulation of transcription.\" width=\"345\" height=\"404\" \/><\/p>\n<p id=\"caption-attachment-3898\" class=\"wp-caption-text\">Figure 1. An enhancer is a DNA sequence that promotes transcription. Each enhancer is made up of short DNA sequences called distal control elements. Activators bound to the distal control elements interact with mediator proteins and transcription factors. Two different genes may have the same promoter but different distal control elements, enabling differential gene expression.<\/p>\n<\/div>\n<p>Genes are organized to make the control of gene expression easier. The <strong>promoter region<\/strong> is immediately upstream of the coding sequence. The purpose of the promoter is to bind transcription factors that control the initiation of transcription.<\/p>\n<h2>Enhancers and Transcription<\/h2>\n<p>In some eukaryotic genes, there are regions that help increase or enhance transcription. These regions, called <strong>enhancers<\/strong>, are not necessarily close to the genes they enhance. They can be located upstream of a gene, within the coding region of the gene, downstream of a gene, or may be thousands of nucleotides away.\u00a0 Enhancer regions are binding sequences, or sites, for transcription factors. When a DNA-bending protein binds, the shape of the DNA changes (Figure 1). This shape change allows for the interaction of the <strong>activators<\/strong> bound to the enhancers with the transcription factors bound to the promoter region and the RNA polymerase.<\/p>\n<h2>Turning Genes Off: Transcriptional Repressors<\/h2>\n<p>Like prokaryotic cells, eukaryotic cells also have mechanisms to prevent transcription. Transcriptional <strong>repressors<\/strong> can bind to promoter or enhancer regions and block transcription. Like the transcriptional activators, repressors respond to external stimuli to prevent the binding of activating transcription factors.<\/p>\n<div class=\"textbox learning-objectives\">\n<h3>In Summary: Eukaryotic Transcription Gene Regulation<\/h3>\n<p>To start transcription, transcription factors,\u00a0 must first bind to the promoter and recruit RNA polymerase to that location. \u00a0 In addition to promoter sequences, enhancer regions help augment transcription. Enhancers can be upstream, downstream, within a gene itself, or on other chromosomes. Transcription factors bind to enhancer regions to increase or prevent transcription.<\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Practice Questions<\/h3>\n<p>The binding of ________ is required for transcription to start.<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>a protein<\/li>\n<li>DNA polymerase<\/li>\n<li>RNA polymerase<\/li>\n<li>a transcription factor<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q670222\">Show Answer<\/span><\/p>\n<div id=\"q670222\" class=\"hidden-answer\" style=\"display: none\">Answer c.\u00a0The binding of RNA polymerase is required for transcription to start.<\/p>\n<\/div>\n<\/div>\n<p>What will result from the binding of a transcription factor to an enhancer region?<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>decreased transcription of an adjacent gene<\/li>\n<li>increased transcription of a distant gene<\/li>\n<li>alteration of the translation of an adjacent gene<\/li>\n<li>initiation of the recruitment of RNA polymerase<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q829037\">Show Answer<\/span><\/p>\n<div id=\"q829037\" class=\"hidden-answer\" style=\"display: none\">Answer b. Increased transcription of a distant gene\u00a0will result from the binding of a transcription factor to an enhancer region.<\/p>\n<\/div>\n<\/div>\n<p>A mutation within the promoter region can alter transcription of a gene. Describe how this can happen.<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"2\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q332179\">Show Answer<\/span><\/p>\n<div id=\"q332179\" class=\"hidden-answer\" style=\"display: none\">A mutation in the promoter region can change the binding site for a transcription factor that normally binds to increase transcription. The mutation could either decrease the ability of the transcription factor to bind, thereby decreasing transcription, or it can increase the ability of the transcription factor to bind, thus increasing transcription.<\/p>\n<\/div>\n<\/div>\n<p>What could happen if a cell had too much of an activating transcription factor present?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"2\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q162780\">Show Answer<\/span><\/p>\n<div id=\"q162780\" class=\"hidden-answer\" style=\"display: none\">If too much of an activating transcription factor were present, then transcription would be increased in the cell. This could lead to dramatic alterations in cell function. \u00a0<\/div>\n<\/div>\n<\/div>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_ddc36758-3e88-4fd6-ad2c-a74640bdbb59\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/ddc36758-3e88-4fd6-ad2c-a74640bdbb59?iframe_resize_id=assessment_practice_id_ddc36758-3e88-4fd6-ad2c-a74640bdbb59\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-3292\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology. <strong>Provided by<\/strong>: OpenStax CNX. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":9,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology\",\"author\":\"\",\"organization\":\"OpenStax CNX\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\"}]","CANDELA_OUTCOMES_GUID":"76d25446-fc1f-444d-9e04-7ff113f3149e, 9ddacb9a-8f64-41c5-ad59-518540047ff5","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-3292","chapter","type-chapter","status-publish","hentry"],"part":3270,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/pressbooks\/v2\/chapters\/3292","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":20,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/pressbooks\/v2\/chapters\/3292\/revisions"}],"predecessor-version":[{"id":6759,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/pressbooks\/v2\/chapters\/3292\/revisions\/6759"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/pressbooks\/v2\/parts\/3270"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/pressbooks\/v2\/chapters\/3292\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/wp\/v2\/media?parent=3292"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/pressbooks\/v2\/chapter-type?post=3292"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/wp\/v2\/contributor?post=3292"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-nmbiology1\/wp-json\/wp\/v2\/license?post=3292"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}