Table 2

Known auxiliary intronic elements that regulate alternative splicing

Exon or intron that is regulated

Type of splice site choice

Specificity of splicing*

Type of element (name)

Sequence

Location of element (nucleotide number relative to alternative exon)

Associated trans factor(s)

Reference


4.1R exon 16 (human)

Cassette

Developmental stage-specific

Enhancer

AUUUAUUuuuAAAUAUuuuUUGGUUUGCCAAUUUUCAGUuuuUCCCG

Upstream (-106 to -59)

Unknown

[53]

4.1R exon 16 (human)

Cassette

Developmental stage-specific

Enhancer

UGUAUgaAcUUGAagcUUAUUUCAgUuGgUUGCCUGgAacCUUCUGCAUUcuUugCUGAUCCCCUUUUCUUCAUUCUgUgcugCAUUUGGUUUugCaUGCAAUUgCauGAAGGGACUUuAGgUuUAAAAUGCuUuUGcAUGUU

Downstream (+4 to 146)

Unknown

[53]

α-actinin NM/SM exons (rat)

Mutually exclusive exons

Smooth muscle-specific

Silencer

Not defined

Upstream of SM exon

PTB

[54]

α-actinin NM/SM exons (rat)

Mutually exclusive exons

Smooth muscle-specific

Enhancer (BP-URE)

CCUUGUCUGUGUGUCUAACUGUGUGCAC

Upstream of NM exon

ETR-3, Brul

[55]

Agrin Y exon (exon 28, mouse)

Cassette

Neuron-specific

Enhancer

uuaccCAACUcaacucaCC

Downstream (+15 to 33)

Unknown

[56]

Agrin Y exon (exon 28, mouse)

Cassette

Neuron-specific

Enhancer

aucuuuuguAGCCAUUCCuagagAGCccuuuccc

Downstream (+34 to 68)

Unknown

[56]

AMP deaminase 1 exon 2 (human)

Cassette

Developmental Stage-specific

Enhancer (ExRE)

GCCCAGGCUGGAGUGCAGUA

Downstream (about +1.7 kb)

Unknown

[57]

AMP deaminase 1 exon 2 (human)

Cassette

Developmental stage-specific

Enhancer (ExRE)

CCAUCGAAUGCAUUUACUU

Downstream (about +3 kb)

Unknown

[57]

Amyloid precursor protein exon 8 (human)

Cassette

Neuron-specific

Enhancer

AUGUUU

Upstream (-47 to -42)

Unknown

[58]

Amyloid precursor protein exon 8 (human)

Cassette

Neuron-specific

Silencer

UUU

Upstream (-38 to -36)

Unknown

[58]

Calcitonin/CGRP exon 4 (human)

Cassette (contains alternative poly(A) site)

Cell type-specific

Enhancer (rep1)

CCAAGGGAAAgcaugGGUUAACCUA

Upstream (-254 to -230)

Unknown

[59]

Calcitonin/CGRP exon 4 (human)

Cassette (contains alternative poly(A) site)

Cell type-specific

Enhancer (rep2)

CAGCCCUGGugcaugGCACUGCCUC

Upstream (-34 to -10)

Unknown

[59]

Calcitonin/ CGRP exon 4 (human)

Cassette (contains alternative poly-A site)

Cell type-specific

Enhancer

CUCCGCUCCUCUUCcagguaagac

Downstream (+204 to 238)

PTB, ASF/SF2 U1 snRNP, SRp20

, [60,61,62]

Cardiac troponin T exon 5 (chicken)

Cassette

Embryonic, muscle-specific

Silencer (MSE1)

CCUCUGCGCUUCUUCCCUUCCCUCCUCCCUGGCUCA

Upstream (-36 to -1)

PTB, U2AF65

[17,63]

Cardiac troponin T exon 5 (chicken)

Cassette

Embryonic, muscle-specific

Enhancer, Silencer (MSE2)

ACUGCACCUUUCUUUGUUCCAUCUCUCCACCUCUGCUGUG

Downstream (+7 to +46)

PTB, ETR-3

[17,64]

Cardiac troponin T exon 5 (chicken)

Cassette

Embryonic, muscle-specific

Enhancer (MSE3)

UCGCGGGUCGGUGUGUCCUGUGCCUUUCCCUGCUU

Downstream (+53 to 87)

ETR-3, PurH

[17,64,65]

Cardiac troponin T exon 5 (chicken)

Cassette

Embryonic muscle-specific

Silencer (MSE4)

CGCUUUCCUUUCAU UCUUUCACUUCUCUGCUGCUUUU

Downstream (+81 to 117)

PTB

[17,64]

Caspase-2 exon 9 (mouse)

Cassette

Brain and skeletal muscle-specific; associated with apoptosis

Silencer (In50 up)

GCUuauuaacUGCAAUGUAcuuuuuauuguuuuucauuccaGUUAAGG

Downstream (+141 to 188)

U2 snRNP

[66,67]

Caspase-2 exon 9 (mouse)

Cassette

Brain and skeletal muscle-specific; associated with apoptosis

Silencer (In50dn)

AUUUCUGCUUGACUCUUCCAAAUCUUCCUUCUCUUACCCUUGCAUUUUCUCUCUGU

Downstream (+189 to 244)

PTB

[66,67]

Chloride channel ClC-1 intron 2 (human)

Intron retention

Aberrant inclusion in myotonic dystrophy

Enhancer

UCUUGGGUAUAGCACCCAAAGUAAAGUAGUGACUCGUUAGCUGCUUUUCUCUCUCUCUCUCUCUCUCUCUCUCUCUCUCUGUCUCUACAUAUAUAUAUUUUUGUUUGUUUGUUUGUUUGUUGUUUGUUUGUUUGUUUUUUCCCUCAUCUC UUCCUAG

Upstream of exon 3 (-156 to -1)

CUG-BP

[2]

Clathrin light chain B exon EN (rat)

Cassette

Neuron-specific

Silencer

CUCUUUCUCUUUAACCCUGUGCCUGCCUGUCUUGCUGUCUGUCUUCCCCCACCUAACUCCUUCUCCUAACGGUUUUCCUCAAG

Upstream (-85 to -1)

PTB, CUG-BP

[68]

c-src N1 exon (mouse)

Cassette

Neuron-specific

Silencer

GGGCCCUGUCUUCGCACCUCAGCCUCUCCUUCUCUCUGCUUCUCUCUCGCUGGCCCUU

Upstream (-60 to -3)

PTB/nPTB

[69]

c-src N1 exon (mouse)

Cassette

Neuron-specific

Enhancer, silencer (DCS)

UGAGGCUGGGGGCUGCUCUCUGCAUGUGCUUCCU

Downstream (+37 to 70)

PTB/nPTB, KSRP, FBP, hnRNP H, hnRNP F

[69,70,71]

Cystic fibrosis transmembrane regulator exon 9 (human)

Cassette

Aberrantly skipped in cystic fibrosis

Silencer (ISS)

Not published

Downstream (+117 to 264)

SR proteins

[72]

Dopa decarboxylase exon B (Drosophila)

Cassette

Tissue-specific

Silencer

Not published

Upstream (+84 to 528)

Unknown

[73]

DMPK exon 16 (human)

Alternative terminal exon

Developmental stage-specific; skipped in DM

Enhancer

(CUG)n

Upstream (about 35 nucleotides)

Unknown

[74]

Fibroblast growth factor receptor 1 α exon (human)

Cassette

Skipped in glial cell tumors

Silencer (ISS-1)

AAugcugcUACAGCUGC UUCCUAACUUUGCCUCUUUCUUC

Upstream (-242 to -281)

PTB*

[75,76]

Fibroblast growth factor receptor 1 α exon (human)

Cassette

Skipped in glial cell tumors

Silencer (ISS-2)

AUCUGCCCCCACUCUGCUUCAGAAACugcugcCCACUAACAUUGCUCCCugccugcCGCGUG

Downstream (+98 to 159)

Unknown

[77]

Fibroblast growth factor receptor 2 BEK/K-SAM (IIIb/IIIc) exons (human)

Mutually exclusive exons

Cell-type specific

Enhancer (IAS1)

CUUUCAUUUUUGUCUUUUUUU

Downstream of K-SAM (+10 to 29)

TIA-1

[78,79]

Fibroblast growth factor receptor 2 BEK/K-SAM (IIIb/IIIc) exons (human)

Mutually exclusive exons

Cell-type specific

Enhancer (IAS2)

CCAUGGAAAAAUGCC CACAAC

Downstream of K-SAM (+168 to 188)

Unknown

[80]

Fibroblast growth factor receptor 2 BEK/K-SAM (IIIb/IIIc) exons (human)

Mutually exclusive exons

Cell-type specific

Enhancer (IAS3)

UGUGGGUUGAUUUUUUCCAUGCGUUUGAUUGCGUGCAUGUGUAGGAGGUGAAGCCGGUGU

Downstream of K-SAM (+963 to 1021)

Unknown

[80]

Fibroblast growth factor receptor 2 IIIb/IIIc exons (rat)

Mutually exclusive exons

Cell-type specific

Enhancer (IIIb), silencer (IIIc) (ISAR)

CAAACAAAUUCAAAGAGAACGGACUCUGUgggcugauuuuuccauguGUUCAAUCGC

Downstream of IIIb (+915 to 978)

Unknown

[81]

Fibroblast growth factor receptor 2 IIIb/IIIc exons (rat)

Mutually exclusive exons

Cell-type specific

Silencer (ISS1)

CUCAUUGUGAUCUCCUCCCUCCCACAGCUCUUUAGGUGUA

Upstream of IIIb (-143 to -112)

PTB

[82]

Fibroblast growth factor receptor 2 IIIb/IIIc exons (rat)

Mutually exclusive exons

Cell-type specific

Silencer (ISS2)

UGGUGGGACCAUAGGCAGCAC

Upstream of IIIb

Unknown

[82]

Fibronectin exon EIIIB (rat)

Cassette

Cell-type specific

Enhancer (ICR)

UCUUAAAGGUUCUCUGCCCugcaugGGAAGAAACAUUGCUGAGAACCACUGugcaugAACCCCCUCACUUGUGAUACGAGUUCACUGAAUGACAUUACGGCAAUGCAGUAGUGUGUAGAUAC

Downstream (+519 to 640)

Unknown

[83,84]

GABAA receptor subunit γ2 24 nucleotide exon (rat)

Cassette

Neuron-specific

Silencer (rs1)

UGUUUCUCUUUCUCUCCUUU

Upstream (-89 to -70)

PTB

[85]

GABAA receptor subunit γ2 24 nucleotide exon (rat)

Cassette

Neuron-specific

Silencer (rs2)

CCUUUUCCUUCUUCUUAUU

Upstream (-69 to -51)

PTB

[85]

GABAA receptor subunit γ2 24 nucleotide exon (rat)

Cassette

Neuron-specific

Silencer (rs3)

GCAAUUCUCUUUUCUGUCU

Upstream (-31 to -13)

PTB

[85]

GABAA receptor subunit γ2 24 nucleotide exon (rat)

Cassette

Neuron-specific

Enhancer

ACAAAUCCA

Upstream (-12 to -4)

Unknown

[85,86]

gag gene (Rous sarcoma virus)

Spliced versus unspliced

Infection stage-specific

Silencer (NRS)

CCGGAGUGCUCGAGAAACCAGCAACGGAGCGGCGAAUCGACAAAGGGGAGGAAGUGGGAGAAACAACUGUGCAGCGAGAUGCGAAGAUGGCGCCGGAGGAAACGGCCACACCUAAAACCGUUGGCACAUCCUGCUAUCAUUGCGGAACAGCUAUUGGCUGUAAUUGCGccacagccucggcucccuccuccuccuuauguggggagugguuuguauccuucccu

Downstream of 5 splice site (about 300 nucleotides)

hnRNP H, SF2/ASF

[87,88,89]

Glycine receptor α2 exon 3A (human)

Cassette

Neuron-specific

Enhancer

UCAUCAUCAUUUCAU

Upstream (about 80 nucleotides)

Nova-1

[31,90]

hnRNP A1 exon 7B (mouse)

Cassette

Auto-regulated

Enhancer (CE1)

UAAGGAGUCUGUAAGUAAUGGUUUCUGGAAAACCUGUACCUUUAGAGUAGGCUAGUAGAAACUAAACUUAGUGCAUGACAAAGUUCGAUCAGUCCCAUAAAUGUGCAUG

Upstream (-194 to -86)

hnRNP A1

[21]

hnRNP A1 exon 7B (mouse)

Cassette

Auto-regulated

Enhancer (CE4)

AGCUAGAUUAGACUU CUAGAGUUU

Downstream (+35 to 58)

hnRNP A1

[21,91]

hnRNP A1 exon 7B (mouse)

Cassette

Auto-regulated

Silencer (CE6IO)

CCUGCUCUGCUGUGCUACCUCCUCCUGGCUUUAAGCUGGGGCCGCCUCCCCAAAAUAAGUAGGUGAAUGAGUGGUUA

Downstream (+128 to 204)

Unknown

[11]

hnRNP A1 exon 7B (mouse)

Cassette

Auto-regulated

Silencer (CE9)

CUGGAUUAUUAACUGAAUGCCUCACUCAGAGAAUGAA

Downstream (+372 to 418)

Unknown

[92]

Major late region 1 (L1) 52,55K/IIIa (adenovirus)

Alternative 3' splice sites

Infection stage-specific

Silencer

GCGUGGAGGAAUAUGACGAGGACGAUGAGUACGAGCCAGAGGACGGCGA

Upstream of IIIa splice site (-76 to -28)

SR proteins

[93]

Major late region 1 (L1) 52,55K/IIIa (adenovirus)

Alternative 3' splice sites

Infection stage-specific

Enhancer

AGUACUAAGCggugauguuucugaucag

Upstream of IIIa splice site (-28 to -1)

Unknown

[94]

MVM NS2-specific exon and small intron (parvovirus)

Cassette, alternative 5' and 3' splice sites

Infection stage-specific

Enhancer (IES)

GUUUAAGggAUgGUUgGUUgGUGgggU

Downstream of NS2 exon, small intron D2 5 splice site

Unknown

[95]

Myosin heavy chain exon 11e (Drosophila)

Mutually exclusive exons 11a-e

Muscle type-specific

Silencer (CIE1)

AUGUACCAUGUACC

Downstream of exon 11e

Unknown

[96]

Myosin heavy chain exon 11e (Drosophila)

Mutually exclusive exons 11a-e

Muscle type-specific

Enhancer (CIE2)

AGUGCUGUGU

Downstream of exon 11e

Unknown

[96]

Myosin heavy chain exon 11e (Drosophila)

Mutually exclusive exons 11a-e

Muscle type-specific

Enhancer (CIE3)

AUCCAUCCCUCUAUCUAUCCCAGUUCAACCUGUCCAAAAGUGUUUUUGAAGAACCGCUUAAGCAUAAGCAAAAAAA

Upstream of exon 12 (about -200 nucleotides)

Unknown

[96]

NCAM MSDb exon (mouse)

Cassette

Muscle-specific, developmental stage-specific

Silencer (DSRE)

GACCUCACUGACCCAGCUGGGCCUUUGUCACAUUGGGGGAGCCUGGUUCUUUUCCUCUCAUUCUCUUAACUGUCUAUACUUUAGUUCUUUGAAUCUGGAGGAGUGGAACAGGUCCACUCUUUGGAAACUUGAACCUGGCUUUCUAGU

Downstream (+626 to 771)

Unknown

[97]

NMDA exon 5 (rat)

Cassette

Neuron-specific

Silencer

GCUUUAGCGCCGUCAUUUUCAACCGUUUAUAAUCUUCUUCUGUGUCUGCAUAUUUUCUCUGUGCACAUUAUUCAUCAG

Upstream (-78 to -1)

PTB, CUG-BP

[68]

Non-muscle myosin II heavy chain B exon N30 (human)

Cassette

Neuron-specific

Enhancer (IDDE)

GAUUugcaugucguacugcauguGUCCACUGUGCACACAAUC

Downstream (+1.5 kb)

Unknown

[98]

Nova-1 exon H (mouse)

Cassette

Neuron-specific

Enhancer

GCCAAUCAGGUACAGUAUCAUCCUCUCAUCCUACACCAUACUUUCACAGCGGUUG

Downstream (+8 to 62)

Nova-1

[31]

sex lethal exon 3 (Drosophila)

Cassette

Male-specific

Silencer

UUUUUUUU

Upstream (-6 to -13)

Sxl

[99]

Slo K+ channel STREX exon (mouse)

Cassette

Ca2+-dependent in neurons

Silencer (CaRRE)

CCUUGCCAUUAACCGCGcUcUUCcUcUCCUCCCAUCCACCACAUGGUUAUAG

Upstream (-53 to -1)

Unknown

[100]

tat intron 2 (HIV-1)

Intron retention

Variable

Silencer (ISS)

UAGUGAAUAGAGUUAGGCAGGGA

Upstream of SA7 splice site (-44 to -22)

hnRNP A1

[101]

tau exon 10 (human)

Cassette

Aberrantly spliced in disease

Silencer (ISS)

UCACACGU

Downstream (+11 to 18)

Unknown

[102]

tau exon 10 (human)

Cassette

Aberrantly spliced in disease

Enhancer (ISM)

CCCAUGCG

Downstream (+19 to 26)

Unknown

[103]

Thyroid hormone receptor exon 9 (rat)

Alternative 5' splice site

Tissue and developmental stage-specific

Enhancer (SEα2)

GGCGGCCAGAgggUGUGCggagcugguggggaggagCUUggagagaagggaCAAAGCUgggggCUgagggagaaCCCCCA

Downstream (+130 to 210)

SF2/ASF, hnRNP H

[104,105]

transformer exon 2 (Drosophila)

Alternative 3' splice site

Sex-specific

Enhancer

Not published

Downstream of non-sex-specific 3 splice site (about 40 nucleotides)

Unknown

[106]

transformer exon 2 (Drosophila)

Alternative 3' splice site

Sex-specific

Silencer of non-sex-specific 3 splice site

UUUUUUUU

Upstream of non-sex-specific 3 splice site (-4 to -11)

Sxl, U2 snRNP

[107,108]

α-tropomyosin exons 2/3 (rat)

Mutually exclusive exons

Smooth muscle-specific

Silencer (URE)

aucacgcugccugcugcaCCCCACCCCCUUCCCCCUUCCUUCCCCCCACCCCCGUACUCCACUGCCAACUCCC

Upstream of exon 3 (-75 to -1)

Unknown

[109,110,111]

α-tropomyosin exons 2/3 (rat)

Mutually exclusive exons

Smooth muscle-specific

Silencer (DRE)

CUGGAUGCCGCCUCUGCUGCUGCGCACAUUUCAUUUAUAUUCUGUCCUUUCCCCUUUUUCUCCUCUUCUUUACCUCCUCCCCUUUGGUUG

Downstream of exon 3 (+142 to 231)

PTB

[109,110,111]

β-tropomyosin exons 6A/6B (chicken)

Mutually exclusive exons

Skeletal muscle-specific

Enhancer (S4)

CCCCUCUCUCUAUCGCUGUCUCUUGAGCCACGC

Downstream of exon 6A (+37 to 69)

ASF/SF2, SC35, PTB, hnRNP K

[112,113,114,115]

β-tropomyosin exons 6A/6B (chicken)

Mutually exclusive exons

Skeletal muscle-specific

Enhancer (IVS B7)

GCUGGGGCUGGGCAGAGCGCGCAGGGUUGAGGGGAGCAGGGUCCUUCACUGGGGUGAA

Downstream of exon 6B (+19 to 76)

TLS

[116,117]

β-tropomyosin exons 6/7 (rat)

Mutually exclusive exons

Striated muscle-specific

Silencer (IRE)

AACCCCACCCCCUCACCCCGUCGUCGCGCCACCCCACUGUCUCACCUCACUGUGCCCUCACGCUCCAUCCUGCCACACGCCCCUGCAG

Upstream of exon 7 (-88 to -1)

PTB, Sam68, FBP

[118,119]


*Elements listed may not have been shown to regulate the specificity of alternative splicing. Sequences that have been shown to be important for element function but that have not yet been demonstrated to bind to specific trans-acting factors are shown in lower-case letters. Indicates that the factor has been shown to bind directly to the element (for example, by ultraviolet-induced crosslinking) and has had binding confirmed (for example, by mutational analysis). Specific binding sequences for trans-actingfactors are indicated in bold, italics or underlined when known.

Ladd and Cooper Genome Biology 2002 3:reviews0008.1   doi:10.1186/gb-2002-3-11-reviews0008