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Suggestive evidence on the involvement of polypyrimidine-tract binding protein in regulating alternative splicing of MAP/microtubule affinity-regulating kinase 4 in glioma.
Cancer Lett. 2015 Apr 01; 359(1):87-96.CL

Abstract

MAP/microtubule affinity-regulating kinase 4 (MARK4) is a serine-threonine kinase that phosphorylates microtubule-associated proteins taking part in the regulation of microtubule dynamics. MARK4 is expressed in two spliced isoforms characterized by inclusion (MARK4S) or exclusion (MARK4L) of exon 16. The distinct expression profiles in the central nervous system and their imbalance in gliomas point to roles of MARK4L and MARK4S in cell proliferation and cell differentiation, respectively. Having ruled out mutations and transcription defects, we hypothesized that alterations in the expression of splicing factors may underlie deregulated MARK4 expression in gliomas. Bioinformatic analysis revealed four putative polypyrimidine-tract binding (PTB) protein binding sites in MARK4 introns 15 and 16. Glioma tissues and glioblastoma-derived cancer stem cells showed, compared with normal brain, significant overexpression of PTB, correlated with high MARK4L mRNA expression. Splicing minigene assays revealed a functional intronic splicing silencer in MARK4 intron 15, but mutagenesis of the PTB binding site in this region did not affect minigene splicing, suggesting that PTB may bind to a splicing silencer other than the predicted one and synergistically acting with the other predicted PTB sites. Electrophoretic mobility shift assays coupled with mass spectrometry confirmed binding of PTB to the polypyrimidine tract of intron 15, and thus its involvement in MARK4 alternative splicing. This finding, along with evidence of PTB overexpression in gliomas and glioblastoma-derived cancer stem cells and differentiated progeny, merged in pointing out the involvement of PTB in the switch to MARK4L, consistent with its established role in driving oncogenic splicing in brain tumors.

Authors+Show Affiliations

Department of Health Sciences, Medical Genetics, Università degli Studi di Milano, via Antonio di Rudinì 8, 20142 Milan, Italy.Department of Health Sciences, Medical Genetics, Università degli Studi di Milano, via Antonio di Rudinì 8, 20142 Milan, Italy.Department of Health Sciences, Medical Genetics, Università degli Studi di Milano, via Antonio di Rudinì 8, 20142 Milan, Italy.Department of Animal Pathology, Hygiene and Veterinary Public Health, Università degli Studi di Milano, Via Celoria, 10, 20133 Milan, Italy; Fondazione Filarete, Viale Ortles 22/4, 20139 Milan, Italy.Department of Animal Pathology, Hygiene and Veterinary Public Health, Università degli Studi di Milano, Via Celoria, 10, 20133 Milan, Italy; Fondazione Filarete, Viale Ortles 22/4, 20139 Milan, Italy.Department of Health Sciences, Medical Genetics, Università degli Studi di Milano, via Antonio di Rudinì 8, 20142 Milan, Italy.Department of Health Sciences, Medical Genetics, Università degli Studi di Milano, via Antonio di Rudinì 8, 20142 Milan, Italy; Laboratory of Medical Cytogenetics and Molecular Genetics, IRCCS Istituto Auxologico Italiano, Via Zucchi, 18, 20095 Cusano Milanino, Italy. Electronic address: lidia.larizza@unimi.it.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

25578778

Citation

Fontana, L, et al. "Suggestive Evidence On the Involvement of Polypyrimidine-tract Binding Protein in Regulating Alternative Splicing of MAP/microtubule Affinity-regulating Kinase 4 in Glioma." Cancer Letters, vol. 359, no. 1, 2015, pp. 87-96.
Fontana L, Rovina D, Novielli C, et al. Suggestive evidence on the involvement of polypyrimidine-tract binding protein in regulating alternative splicing of MAP/microtubule affinity-regulating kinase 4 in glioma. Cancer Lett. 2015;359(1):87-96.
Fontana, L., Rovina, D., Novielli, C., Maffioli, E., Tedeschi, G., Magnani, I., & Larizza, L. (2015). Suggestive evidence on the involvement of polypyrimidine-tract binding protein in regulating alternative splicing of MAP/microtubule affinity-regulating kinase 4 in glioma. Cancer Letters, 359(1), 87-96. https://doi.org/10.1016/j.canlet.2014.12.049
Fontana L, et al. Suggestive Evidence On the Involvement of Polypyrimidine-tract Binding Protein in Regulating Alternative Splicing of MAP/microtubule Affinity-regulating Kinase 4 in Glioma. Cancer Lett. 2015 Apr 1;359(1):87-96. PubMed PMID: 25578778.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Suggestive evidence on the involvement of polypyrimidine-tract binding protein in regulating alternative splicing of MAP/microtubule affinity-regulating kinase 4 in glioma. AU - Fontana,L, AU - Rovina,D, AU - Novielli,C, AU - Maffioli,E, AU - Tedeschi,G, AU - Magnani,I, AU - Larizza,L, Y1 - 2015/01/08/ PY - 2014/10/19/received PY - 2014/12/23/revised PY - 2014/12/26/accepted PY - 2015/1/13/entrez PY - 2015/1/13/pubmed PY - 2015/4/10/medline KW - Alternative splicing KW - Glioma KW - MARK4 KW - PTB KW - Splicing minigene SP - 87 EP - 96 JF - Cancer letters JO - Cancer Lett. VL - 359 IS - 1 N2 - MAP/microtubule affinity-regulating kinase 4 (MARK4) is a serine-threonine kinase that phosphorylates microtubule-associated proteins taking part in the regulation of microtubule dynamics. MARK4 is expressed in two spliced isoforms characterized by inclusion (MARK4S) or exclusion (MARK4L) of exon 16. The distinct expression profiles in the central nervous system and their imbalance in gliomas point to roles of MARK4L and MARK4S in cell proliferation and cell differentiation, respectively. Having ruled out mutations and transcription defects, we hypothesized that alterations in the expression of splicing factors may underlie deregulated MARK4 expression in gliomas. Bioinformatic analysis revealed four putative polypyrimidine-tract binding (PTB) protein binding sites in MARK4 introns 15 and 16. Glioma tissues and glioblastoma-derived cancer stem cells showed, compared with normal brain, significant overexpression of PTB, correlated with high MARK4L mRNA expression. Splicing minigene assays revealed a functional intronic splicing silencer in MARK4 intron 15, but mutagenesis of the PTB binding site in this region did not affect minigene splicing, suggesting that PTB may bind to a splicing silencer other than the predicted one and synergistically acting with the other predicted PTB sites. Electrophoretic mobility shift assays coupled with mass spectrometry confirmed binding of PTB to the polypyrimidine tract of intron 15, and thus its involvement in MARK4 alternative splicing. This finding, along with evidence of PTB overexpression in gliomas and glioblastoma-derived cancer stem cells and differentiated progeny, merged in pointing out the involvement of PTB in the switch to MARK4L, consistent with its established role in driving oncogenic splicing in brain tumors. SN - 1872-7980 UR - https://www.unboundmedicine.com/medline/citation/25578778/Suggestive_evidence_on_the_involvement_of_polypyrimidine_tract_binding_protein_in_regulating_alternative_splicing_of_MAP/microtubule_affinity_regulating_kinase_4_in_glioma_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0304-3835(15)00002-6 DB - PRIME DP - Unbound Medicine ER -