esone1 introne1 esone2 introne2 esone3
esone1
esone1
introne1
esone2
esone2
introne2
esone3
esone3
SPLICING
eliminazione introni
unione esoni
GT GTAG AG
Alcuni modo di fare alternative splicing
Riconoscimento degli introni
Motivi conservati
Meccanismo dello splicing
- SnRNPs (Small nuclear ribonuclear proteins) binds critical sites on the pre-mRNA
- pronounced ‘SNURPs’
- these are complexes containing both protein and small RNAs
- the small RNAs are transcribed by RNA polymerase III
- they then associate with accessory proteins
- the complex then recognizes critical sites for splicing by base pairing
Particelle dello splicing
Particelle che intervengono nello splicing
U1 snRNP
Intron definition exon definition
Modello di exonic splicing enhancer mediato da proteine SR
Modello di exonic splicing silencer
Modelli di splicing silencing
Nell’esone si trovano motivi ESE e ESS sovrapposti, quindi c’è una competizione diretta tra i fattori che stimolano lo splicing (SR) e quelli che lo inibiscono (hnRNP). Il legame di uno o dell’altro elemento è mutuamente esclusivo. A questo punto i fattori importanti diventano la maggiore affinità di legame degli elementi regolativi e la concentrazione di questi.
Modelli di splicing silencing
Fattore inibitori per lo splicing si legano a elementi Intronic Splicing Silencer e per dimerizzazione formano un anello che esclude l’esone
Modelli di splicing silencing
Se non ci sono elementi inibitori l’esone viene incluso, se ci sono elementi inibitori e se questi si legano per primi, promuovono il legame di altri elementi inibitori (polimerizzazione) od ostacolano il legame di elementi rafforzativi
Nonsense mediated decay
Why Splicing?1. The intron-exon arrangement may facilitate the evolution of new proteins through recombination of exons.
2. Splicing increases the coding potential of the genome through alternative splicing.60% of transcripts in human are spliced in different ways.
Cell-type spcific splicing of fibronectin pre-mRNA
attggaaaccgaaacccgttggtcacctctgcaatagccctccctccctcacttctacaattttgtgacagtggtcttgttttctgcattctctgcttcacgtgcttgttttgttggagcgcgtttgcatgctgctttaaattctgaaatattaaaaaaatttcgaagtttttcagcacatgggatgggagttttgaatttcaattttttaaaaacatttttctgtgattagtgccgtcgtggcacggctgttagccgcctatccggtttattcgatactttGTGAGTTTTTTGTAACTTTATGGTCGTCGAAATGGGAAAACTTGGCCACCAATATAAGTTTGGAAAACAATTTCCTAAAAATAAAATAATTGAACTTTTCCGATGAATAAAAAAATCGATCAGATATTCTGGAAAAAAAATCGATAAATTAATCGATTTTCTTGGAAAATACATCGAAAAATTGAGAAAAATAGAAAAATGAATGTTTTTCGATTACCGATTTATTGATTTTTCGTGAAAACTGAGTTCAGATAATTTTAAAAGCAATGTTTTTCATTTTTCAAATCAGAATCACTATAGTTTTGAAAAATCAATAATTAATTTATTGATTTTTCAATATAATTTTTTGGAAAAAATAGAAAAATCCCTTTCTAAAAGTTTTAAATTTCCAAGAAAAATTCATTTTCAAAATCACCAACGCGCTCTATAGAGTAGTCGATGAAAATCTCCGTTAAGGGTGCATGGGCAAAACGCGCTCGAACGACAATTGTTATTGTATGTTTGGTCTTGCAACGAAAAGTTTGAAAAATTGAAAAAAAGTTGTGTCTGATACATTTTTTTTTGGCATTTTCTGCTATTTTACACCAGAAAAAATTTAATAAACATAAAAAATCGAAATTTTTCAAGTTGGACAATTTTCAGtgagcatcttatccatcctagttctcagttcaggacttgtgcacattcgtttagagccagatattcgcaaagccttttcaccggatgattcagatgctggataGTAAGTGACTACTGACCTTGAAGCCTCCTTCCTCCACCAGTCAGAAATAACACGTTTTTTCGCAATGTTTTTCTTTTTCTAATTCGATTTCCCTTTCTCCCTTTCTTATTGTGATTTGGTCAATGTTTGGTTGACTGGGAAGAAAATTGAATTTTTTTGGAATTCCACTTGAAGTTAAAAAACCCAAAATAAATATTTGATCAAAAATAAATAAGAAAAAAAAGAAAACTTTAAAGCAAATGAAAATTTCGTTCGTAACTATTTTGTTAATTTTTTTAAAACTCCTATTTTAAATATATGCTTTTTGCGGAAATTTCTATAAATTTTTTTACATTTTTCAGtgaaacccgtgtctggctggaatactacggactcgacatctatccggaacgagcattctgtatttttaccgccaagcgcgaaaattccagtattctccaggaaggcgcactggcagacGTAAGTTGATTCTCCGTCACGCCCACTTTTCTGGCGGGAATTTAAAAAATTTCAGatttatactgtggacaatcgactatcggcggcagttggctaccaagatggggatggacgaaaaaattgcgatccactctgcgacttgaacagcccctttcacttgttagcgGTAGGTGGTGGTCTAGGGTGTCATTTTTCGATTTTTTCAATTATTCGATGTTTTTAGTGAAAATCGAAAAATCTAAAAATTGAAAATCGAAAAATGAAAGAAACATTGTTTTTTGGGGACCAAACATCTTAATGAATTTAACAACAGGGAAAACTGAACAGAAACCTGGACGGTCTTATCCCATTTATCTATATTCTTAAAATGAATGATGGAGAAAAAAGTTAAAATAAAAACATTATCAGCTTTTTGTAAGTTTTTCTCAAAAATTGTTCGATTTTTCGATTTTCTAAAAAGTCGAAAAACCGAAACCCTTGGTGGTGGTGGTGGTGGACTAGAAAACTCTTCAACGACCACATGGCAATTTTCAGaatttgacgcggagaaacaatggtaccacaagtgtattcacctatccggatatgccatatagcggactggatattttcctgggacttcacttgagtaatgcggattttggtaagattttttttgaaatgttaaatgaaaagttgaaaaatagtttttatgatttagccactttccagttaaaatttcatttttttaactataaaaagttctggaaaaatg
aatttctAGgccgccgatcctaaaAGTgcaccatttcgcAGaAGTacGTacAGTttcccatctatccctAGTgGTcttGTtttctgcattctctgcttcacGTgcttGTtttGTtggAGcgcGTttgcatgctgctttaaattctgaaatattaaaaaaatttcgaAGTttttcAGcacatgggatgggAGTtttgaatttcaattttttaaaaacatttttctGTgattAGTgccGTcGTggcacggctGTtAGccgcctatccgGTttattcgatactttGTGAGTTTTTTGTAACTTTATGGTCGTCGAAATGGGAAAACTTGGCCACCAATATAAGTTTGGAAAACAATTTCCTAAAAATAAAATAATTGAACTTTTCCGATGAATAAAAAAATCGATCAGATATTCTGGAAAAAAAATCGATAAATTAATCGATTTTCTTGGAAAATACATCGAAAAATTGAGAAAAATAGAAAAATGAATGTTTTTCGATTACCGATTTATTGATTTTTCGTGAAAACTGAGTTCAGATAATTTTAAAAGCAATGTTTTTCATTTTTCAAATCAGAATCACTATAGTTTTGAAAAATCAATAATTAATTTATTGATTTTTCAATATAATTTTTTGGAAAAAATAGAAAAATCCCTTTCTAAAAGTTTTAAATTTCCAAGAAAAATTCATTTTCAAAATCACCAACGCGCTCTATAGAGTAGTCGATGAAAATCTCCGTTAAGGGTGCATGGGCAAAACGCGCTCGAACGACAATTGTTATTGTATGTTTGGTCTTGCAACGAAAAGTTTGAAAAATTGAAAAAAAGTTGTGTCTGATACATTTTTTTTTGGCATTTTCTGCTATTTTACACCAGAAAAAATTTAATAAACATAAAAAATCGAAATTTTTCAAGTTGGACAATTTTCAGtgAGcatcttatccatcctAGTtctcAGTtcAGgacttGTgcacattcGTttAGAGccAGatattcgcaaAGccttttcaccggatgattcAGatgctggatAGTAAGTGACTACTGACCTTGAAGCCTCCTTCCTCCACCAGTCAGAAATAACACGTTTTTTCGCAATGTTTTTCTTTTTCTAATTCGATTTCCCTTTCTCCCTTTCTTATTGTGATTTGGTCAATGTTTGGTTGACTGGGAAGAAAATTGAATTTTTTTGGAATTCCACTTGAAGTTAAAAAACCCAAAATAAATATTTGATCAAAAATAAATAAGAAAAAAAAGAAAACTTTAAAGCAAATGAAAATTTCGTTCGTAACTATTTTGTTAATTTTTTTAAAACTCCTATTTTAAATATATGCTTTTTGCGGAAATTTCTATAAATTTTTTTACATTTTTCAGTgaaacccGTGTctggctggaatactacggactcgacatctatccggaacgAGcattctGTatttttaccgccaAGcgcgaaaattccAGTattctccAGgaAGgcgcactggcAGacGTAAGTTGATTCTCCGTCACGCCCACTTTTCTGGCGGGAATTTAAAAAATTTCAGatttatactGTggacaatcgactatcggcggcAGTtggctaccaAGatggggatggacgaaaaaattgcgatccactctgcgacttgaacAGcccctttcacttGTtAGcgGTAGGTGGTGGTCTAGGGTGTCATTTTTCGATTTTTTCAATTATTCGATGTTTTTAGTGAAAATCGAAAAATCTAAAAATTGAAAATCGAAAAATGAAAGAAACATTGTTTTTTGGGGACCAAACATCTTAATGAATTTAACAACAGGGAAAACTGAACAGAAACCTGGACGGTCTTATCCCATTTATCTATATTCTTAAAATGAATGATGGAGAAAAAAGTTAAAATAAAAACATTATCAGCTTTTTGTAAGTTTTTCTCAAAAATTGTTCGATTTTTCGATTTTCTAAAAAGTCGAAAAACCGAAACCCTTGGTGGTGGTGGTGGTGGACTAGAAAACTCTTCAACGACCACATGGCAATTTTCAGaatttgacgcggAGaaacaatgGTaccacaAGTGTattcacctatccggatatgccatatAGcggactggatattttcctgggacttcacttgAGTaatgcggattttgGTaAGattttttttgaaatGTtaaatgaaaAGTtgaaaaatAGTttttatgatttAGccactttccAGTtaaaatttcatttttttaactataaaaAGTtctggaaaaatG
Distribuzione dimensioni introni C.elegans
0,00
0,01
0,02
0,03
0,04
0,05
0,06
0,07
0,08
0,09
202326293235384144475053565962656871747780838689929598101
104
107
110
113
116
119
122
125
128
131
134
137
140
143
146
149
152
155
158
161
164
167
170
dimensioni
freq
uenz
e
Sequenze in testa negli introni di C.elegans
gtaagtt
gtaattt
gtacgtt
gtaggtt
gtatgtt
gtattttgtcagtt
gtgagtt
gtgggtt
gttagtt
gtgagaa
gttcgttgttggtt
gtttgtt
gtgtgttgtgcgtt
0,00
0,02
0,04
0,06
0,08
0,10
gtaaaaa
gtaagac
gtacaag
gtacgat
gtagaca
gtaggcc
gtatacg
gtatgct
gtcaaga
gtcaggc
gtccagg
gtccggt
gtcgata
gtcggtc
gtctatg
gtctgtt
gtgacaa
gtgatac
gtgccag
gtgctat
gtggcca
gtggtcc
gtgtccg
gtgttct
gttacga
gttatgc
gttccgg
gttctgt
gttgcta
gttgttc
gtttctg
gtttttt
basi
freq
uenz
e
Sequenze in coda negli introni di C.elegans
tttccag
ttttcag
tcttcagtattcag
gtttcagctttcag
atttcag
agttcagacttcagaattcag
0,00
0,05
0,10
0,15
0,20
0,25
aaaaaag
aagaaag
acaaaag
acgaaag
agaaaag
aggaaag
ataaaag
atgaaag
caaaaag
cagaaag
ccaaaag
ccgaaag
cgaaaag
cggaaag
ctaaaag
ctgaaag
gaaaaag
gagaaag
gcaaaag
gcgaaag
ggaaaag
gggaaag
gtaaaag
gtgaaag
taaaaag
tagaaag
tcaaaag
tcgaaag
tgaaaag
tggaaag
ttaaaag
ttgaaag
basi
freq
uenz
e
Terne che precedono gli introni in C.elegans
0,00
0,02
0,04
0,06
0,08
0,10
0,12
0,14
aaa
taa
gca
cga
ata
tta
gac
ccc
agc
tgc
gtc
cag
acg
tcg
ggg
ctg
aat
tat
gct
cgt
att
ttt
basi
freq
uenz
e