Exon Topics

• untranslated sequences
• target gene
• dna template
• human genes
• exon structure
• exons
• amino acids
• reporter gene
• splices
• mrna
• orf
• chromosome
• rna
• stretches
• half life
• scientist
• transcripts
• translation

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• wpedia_genetics
• wpedia_genomics
• exon
• mrna
• dna
• uolmb1001-08

Exon, Exon

This is incorrect, since many noncoding exons are known in human genes (Zhang 1998).

Exons can include both sequences that code for amino acids (red) and untranslated sequences (grey). Stretches of unused sequence called introns (blue) are removed, and the exons are joined together to form the final functional mRNA. The notation 5' and 3' refer to the direction of the DNA template in the chromosome and is used to distinguish between the two untranslated regions (grey).

The untranslated regions are important for efficient translation of the transcript and for controlling the rate of translation and half life of the transcript. Furthermore, transcripts made from the same gene may not have the same exon structure since parts of the mRNA could be removed by the process of alternative splicing. Some mRNA transcripts have exons with no ORF's and thus are sometimes referred to as non-coding RNA.

The first exon of a 'trapped' gene splices into the exon that is contained in the insertional DNA. This new exon contains the ORF for a reporter gene that can now be expressed using the enhancer that control the target gene. A scientist knows that a new gene has been trapped when the reporter gene is expressed.

Source: Wikipedia > Exon