Evo Devo

Evolutionary development - at the biological interface between genetic regulatory mechanisms and biological evolution.


Exonic splicing silencers.
Exonal sequences have a prominent role in promoting exon definition and inclusion in mature transcripts (mRNA). Sequences that act as exonic splicing silencers (ESSs) have been described (611) but are less well characterized than ESEs. In some instances, ESSs have been shown to bind negative regulators belonging to the heterogeneous nuclear ribonucleoprotein (hnRNP) family (11,12).

The best understood exonic elements include the so-called exonic splicing enhancers (ESEs). ESEs provide binding sites for serine rich, SR proteins, which are thought to have a role in the initial steps of spliceosome assembly (35).

ESEs and the ESSs are capable of regulating splicing of heterologous pre-mRNAs containing suboptimal splice sites. The function of ESEs and ESSs appears to be especially important for the regulation of alternative splicing events, but these sequences probably also play a relevant role in the definition of constitutive exons.


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