Exonic splicing enhancer

In

).

Introduction

Short sequences of DNA are transcribed to

out the introns, sections of RNA that do not code for the protein. The presence of exonic splicing enhancers is essential for proper identification of splice sites by the cellular machinery.

Role in splicing

SR proteins bind to and promote exon splicing in regions with ESEs, while heterogeneous ribonucleoprotein particles (hnRNPs) bind to and block exon splicing in regions with exonic splicing silencers. Both types of proteins are involved in the assembly and proper functioning of spliceosomes.^[1]

During RNA splicing, U2 small nuclear RNA auxiliary factor 1 (U2AF35) and U2AF2 (U2AF65) interact with the branch site and the 3' splice site of the intron to form the lariat. It is thought that SR proteins that bind to ESEs promote exon splicing by increasing interactions with U2AF35 and U2AF65.^[2]

Mutation of exonic splicing enhancer motifs is a significant contributor to genetic disorders and some cancers. Simple point mutations in ESEs can inhibit affinity for splicing factors and alter alternative splicing, leading to altered mRNA sequence and protein translation. A field of genetic research is dedicated to determining the location and significance of ESE motifs in vivo.^[3]

Research

Computational methods were used to identify 238 candidate ESEs.

located in an ESEs can lead to exon skipping and the production of a non functioning protein.

Disruption of an exon splicing enhancer in exon 3 of

There is evidence that these 236 hexamers that signal splicing are evolutionarily conserved.[6]

See also

• Exonic splicing silencer (ESS)

References

External links

• ESE finder