Difference between revisions of "Intron"
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| − | An '''Intron''' is a non-protein-coding sequence of [[DNA]] that is initially copied into [[RNA]] but is cut out of the final RNA transcript (mature mRNA). They are found in most multicellular eukaryotes. They are rare or absent in most unicellular eukaryotes and prokaryotes, but present in the DNA of viruses that infect eukaryotic cells. In contrast to introns, the protein-coding segments of DNA are called [[exon]]s. The presence of introns in many genes can cause problems with protein purification when bacteria are used to propagate a protein, as they lack the machinery to excise introns from genes. The gene containing the protein to be purified must have its introns excised before being subcloned into a suitable plasmid. This is often done using a cDNA library. | + | An '''Intron''' is a non-protein-coding sequence of [[DNA]] that is initially copied into [[RNA]] but is cut out of the final RNA transcript (mature mRNA). They are found in most multicellular eukaryotes. They are rare or absent in most unicellular eukaryotes and prokaryotes, but present in the DNA of viruses that infect eukaryotic cells. In contrast to introns, the protein-coding segments of DNA are called [[exon]]s. The presence of introns in many genes can cause problems with protein purification when bacteria are used to propagate a protein, as they lack the machinery to excise introns from genes. The gene containing the protein to be purified must have its introns excised before being subcloned into a suitable plasmid. This is often done using a [[cDNA library]]. |
== Sources == | == Sources == | ||
Revision as of 23:45, May 18, 2008
An Intron is a non-protein-coding sequence of DNA that is initially copied into RNA but is cut out of the final RNA transcript (mature mRNA). They are found in most multicellular eukaryotes. They are rare or absent in most unicellular eukaryotes and prokaryotes, but present in the DNA of viruses that infect eukaryotic cells. In contrast to introns, the protein-coding segments of DNA are called exons. The presence of introns in many genes can cause problems with protein purification when bacteria are used to propagate a protein, as they lack the machinery to excise introns from genes. The gene containing the protein to be purified must have its introns excised before being subcloned into a suitable plasmid. This is often done using a cDNA library.
Sources
http://www.genome.gov/glossary.cfm?key=intron
Molecular Cell Biology, 5th ed. Lodish et al. New York: W. H. Freeman and Co, 2004. pp 111-112.
