Coupled transcription-splicing regulation of mutually exclusive splicing events at the 5' exons of protein 4.1R gene.
The tightly regulated production of distinct erythrocyte protein 4.1R isoforms involves differential splicing of 3 mutually exclusive first exons (1A, 1B, 1C) to the alternative 3' splice sites (ss) of exon 2'/2. Here, we demonstrate that exon 1 and 2'/2 splicing diversity is regulated by a transcription-coupled splicing mechanism. We also implicate distinctive regulatory elements that promote the splicing of exon 1A to the distal 3' ss and exon 1B to the proximal 3' ss in murine erythroleukemia cells. A hybrid minigene driven by cytomegalovirus promoter mimicked 1B-promoter-driven splicing patterns but differed from 1A-promoter-driven splicing patterns, suggesting that promoter identity affects exon 2'/2 splicing. Furthermore, splicing factor SF2/ASF ultraviolet (UV) cross-linked to the exon 2'/2 junction CAGAGAA, a sequence that overlaps the distal U2AF(35)-binding 3' ss. Consequently, depletion of SF2/ASF allowed exon 1B to splice to the distal 3' ss but had no effect on exon 1A splicing. These findings identify for the first time that an SF2/ASF binding site also can serve as a 3' ss in a transcript-dependent manner. Taken together, our results suggest that 4.1R gene expression involves transcriptional regulation coupled with a complex splicing regulatory network.
Huang
Shu-Ching
SC
Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA. shu-ching_huang@dfci.harvard.edu
Cho
Aeri
A
Norton
Stephanie
S
Liu
Eva S
ES
Park
Jennie
J
Zhou
Anyu
A
Munagala
Indira D
ID
Ou
Alexander C
AC
Yang
Guang
G
Wickrema
Amittha
A
Tang
Tang K
TK
Benz
Edward J
EJ
D020121:5' Untranslated Regions; D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D001798:Blood Proteins / Q000096:biosynthesis / Q000235:genetics*; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000096:biosynthesis / Q000235:genetics*; D004257:DNA Polymerase II / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005091:Exons; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D051379:Mice; D008840:Microfilament Proteins; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics; D016601:RNA-Binding Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D000068103:Serine-Arginine Splicing Factors; D000072668:Splicing Factor U2AF; D014018:Tissue Distribution; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D020121:5' Untranslated Regions; D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D017931:DNA Primers; C514956:Epb41 protein, mouse; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D000072668:Splicing Factor U2AF; C494908:Srsf1 protein, mouse; C000607494:U2AF2 protein, human; C000607495:Zrsr1 protein, mouse; C028841:erythrocyte membrane band 4.1 protein; D000068103:Serine-Arginine Splicing Factors; D004257:DNA Polymerase II