Name: genes, introns, and regulatory dna
Uploaded: 2026-08-26T08:20:12.834Z
Duration: 2 min 39 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

Structure and Function

3.1.9-12.A

Organization of Genes

- [Instructeur] Naast de complexe rangschikking van genetisch materiaal in de kern van een cel, tonen menselijke genen ook hun eigen unieke organisatie.
 Verspreid tussen de chromosomen zijn meer dan 20.000 genen, soms gescheiden door enorme stukken niet-coderend DNA, of dat wat eiwitten niet codeert.
Sleutel tot de organisatie van een individueel gen is de promotor waaraan machines, met name RNA-polymerase, kunnen hechten.
 Wanneer dit enzym een nabijgelegen transcriptie-initiatieplaats herkent, begint het een streng RNA te genereren, met behulp van DNA als sjabloon.
 De polymerase doorkruist dan het genetische materiaal en blijft RNA opleveren, totdat het de transcriptie-terminatiesequentie van een gen identificeert, waardoor het proces stopt.
Belangrijk is dat tussen deze begin- en eindpunten gebieden liggen die introns en exons worden genoemd, die beide worden weerspiegeld in het RNA-product.
 Volgende processen verwijderen echter introns uit dit transcript.
 Omdat dit RNA zal worden gebruikt om eiwitten te genereren, worden exons aangeduid als coderende regio&#x27;s en introns zijn een voorbeeld van niet-coderend materiaal.
Interessant is dat andere soorten niet-coderend DNA, zoals dempers, ook associ&#xEB;ren met genen.
 Eiwitten, repressoren genoemd, binden aan deze regio&#x27;s, wat de associatie tussen polymerase en promotor voorkomt en transcriptie remt.
 Als gevolg hiervan helpen dempers genexpressie te reguleren.
Een gen bestaat dus uit verschillende componenten, waaronder een promotor, exons, introns en regulerende elementen, die samen helpen met het bepalen van de eiwitexpressie in een cel.

organisatie van genen

<h4>Overzicht</h4>

De genomen van eukaryoten kunnen in verschillende functionele categorie&#xEB;n worden gestructureerd. Een DNA-streng bestaat uit genen en intergene regio&#x27;s. Genen zelf bestaan uit eiwitcoderende exons en niet-coderende introns. Introns worden uitgesneden zodra de sequentie is getranscribeerd naar mRNA, waardoor alleen exons overblijven om voor eiwitten te coderen.

<h4>Eukaryotische genen worden gescheiden door intergene regio&#x27;s</h4>

In eukaryote genomen worden genen gescheiden door grote ketens DNA die niet coderen voor eiwitten. Deze intergene regio&#x27;s bevatten echter belangrijke elementen die de genactiviteit reguleren, zoals de promotor, waar de transcriptie begint, en versterkers en geluiddempers die genexpressie verfijnen. Soms kunnen deze bindingsplaatsen zich ver weg van het bijbehorende gen bevinden.

<h4>Eiwitcoderende exons worden afgewisseld door introns</h4>

Toen onderzoekers het proces van gentranscriptie in eukaryoten onderzochten, realiseerden ze zich dat het uiteindelijke mRNA dat codeert voor een eiwit korter is dan het DNA waarvan het is afgeleid. Dit lengteverschil wordt veroorzaakt door een proces dat splicing wordt genoemd. Zodra pre-mRNA uit het DNA in de kern is getranscribeerd, worden door splitsing onmiddellijk de introns verwijderd en de exons met elkaar verbonden. Het resultaat is eiwitcoderend mRNA dat naar het cytoplasma beweegt en in eiwit wordt vertaald.

<h4>Het aantal introns per gen kan aanzienlijk vari&#xEB;ren</h4>

Een van de grootste menselijke genen, DMD, is meer dan twee miljoen basenparen lang. Dit gen codeert voor het spiereiwit dystrofine. Mutaties in DMD veroorzaken spierdystrofie, een aandoening die wordt gekenmerkt door progressieve spierverslechtering. Dit gen bevat 79 exons en 103 introns. Aan de andere kant van het spectrum ligt het histone H1A-gen, een van de kleinste genen in het menselijk genoom met een lengte van slechts 781 basenparen, met &#xE9;&#xE9;n exon en geen introns.

<h4>Introns vervullen belangrijke functies</h4>

Zijn introns afval-DNA dat moet worden verwijderd? Interessant genoeg kunnen introns elementen bevatten die belangrijk zijn voor genregulatie. Bovendien maakt het knippen van het initi&#xEB;le transcript en het opnieuw samenvoegen van exons het mogelijk dat DNA-sequenties worden geschud. Dit proces van het mixen en matchen van exons staat bekend als alternatieve splicing. Het maakt het mogelijk om meerdere eiwitvarianten te produceren uit &#xE9;&#xE9;n enkele coderende sequentie.

<h4>De overgrote meerderheid van het menselijk genoom codeert niet voor eiwitten</h4>

Wist je dat 99% van je genoom niet codeert voor eiwitten? In de begindagen van het genoomonderzoek bedachten biologen de pakkende term &#x22;junk-DNA&#x22; voor deze schijnbaar niet-functionele sequenties. Ondertussen hebben we geleerd dat een groot deel van het niet-coderende DNA belangrijke functies vervult. Minstens 9% van het menselijk genoom is betrokken bij genregulatie &#x2013; dat is negen keer meer dan eiwitcoderende sequenties.

Organisatie van genen

Overview

The genomes of eukaryotes can be structured in several functional categories. A strand of DNA is comprised of genes and intergenic regions. ...

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genes, introns, and regulatory dna

Eukaryotic genes are arranged within DNA along with non-coding regions that help control gene activity. A DNA strand includes genes and intergenic regions, which are the stretches between genes. These regions do not code for proteins, but they can contain important regulatory elements such as promoters, enhancers, and silencers.

A gene itself is not a single continuous coding block. It usually contains protein-coding exons and non-coding introns. After DNA is transcribed into pre-mRNA in the nucleus, splicing removes the introns and joins the exons together. The shorter mRNA then moves to the cytoplasm, where it is translated into protein.

The number of introns in a gene can vary a lot. The human DMD gene is more than two million base pairs long and encodes dystrophin, a muscle protein. Mutations in DMD can cause muscular dystrophy, a disease that leads to progressive muscle deterioration. This gene has 79 exons and 103 introns. In contrast, the histone H1A gene is only 781 base pairs long and has one exon and no introns.

Introns are not always useless DNA. Some introns contain elements that help regulate genes. They also support alternative splicing, a process that mixes and matches exons after transcription. This lets one coding sequence produce several protein variants.

Most of the human genome does not code for proteins. Early genome research called many of these sequences junk DNA, but scientists now know that much of this non-coding DNA has important roles. At least 9% of the human genome is involved in gene regulation, which is far more than the protein-coding portion.

Genes, Introns, and Regulatory DNA

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organization of genes

Eukaryotic genes are arranged within DNA along with non-coding regions that help control gene activity. A DNA strand includes genes and intergenic regions, which are the stretches between genes. These regions do not code for proteins, but they can contain important regulatory elements such as promoters, enhancers, and silencers. A gene itself is not a single continuous coding block. It usually contains protein-coding exons and non-coding introns. After DNA is transcribed into pre-mRNA in the...

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mismatch repair

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DNA mismatch repair fixes copying errors that happen during DNA replication. When DNA polymerase makes a mistake, the cell can detect a wrong base pair, such as A with G or T with C, and replace it with the correct nucleotide. This repair system works in both prokaryotes and eukaryotes and depends on several proteins. The Mutator protein family plays a central role in this process. In bacteria such as Escherichia coli, MutS first binds the mismatch. MutL then helps identify which strand is the...

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transcription

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Transcription and gene control explain how cells make RNA from DNA and decide which genes are active. RNA polymerase copies a DNA sequence into RNA, and this is the first step in making a protein from a gene. Many other proteins and control sequences help make messenger RNA, or mRNA, correctly. In eukaryotes, the DNA is first copied into a primary RNA, also called pre-mRNA. This RNA can then be processed into mature mRNA, which serves as the template for protein synthesis. In prokaryotes such...

translation

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Griffith’s Mouse Experiment and DNA

Bacterial transformation explains how DNA can move into bacteria and change their traits. Frederick Griffith first noticed this in 1928 while studying pneumonia-causing Streptococcus pneumoniae in mice. He compared one pathogenic strain with one non-pathogenic strain and found that only the pathogenic strain killed the host mice. Griffith made an unexpected discovery when he killed the pathogenic bacteria and mixed their remains with live, non-pathogenic bacteria. The mixture killed the mice,...

key terms and concepts

Explore how eukaryotic genes are organized with exons, introns, intergenic regions, and regulatory DNA, plus how splicing and alternative splicing work.

Genes, Introns, and Regulatory DNA | JoVE K12

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Genes, Introns, and Regulatory DNA

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