PMID- 26972759 OWN - NLM STAT- MEDLINE DCOM- 20170531 LR - 20171109 IS - 1742-4658 (Electronic) IS - 1742-464X (Linking) VI - 283 IP - 10 DP - 2016 May TI - Polypyrimidine tract-binding protein binds to the 5' untranslated region of the mouse mammary tumor virus mRNA and stimulates cap-independent translation initiation. PG - 1880-901 LID - 10.1111/febs.13708 [doi] AB - The 5' untranslated region (UTR) of the full-length mRNA of the mouse mammary tumor virus (MMTV) harbors an internal ribosomal entry site (IRES). In this study, we show that the polypyrimidine tract-binding protein (PTB), an RNA-binding protein with four RNA recognition motifs (RRMs), binds to the MMTV 5' UTR stimulating its IRES activity. There are three isoforms of PTB: PTB1, PTB2, and PTB4. Results show that PTB1 and PTB4, but not PTB2, stimulate MMTV-IRES activity. PTB1 promotes MMTV-IRES-mediated initiation more strongly than PTB4. When expressed in combination, PTB1 further enhanced PTB4 stimulation of the MMTV-IRES, while PTB2 fully abrogates PTB4-induced stimulation. PTB1-induced stimulation of MMTV-IRES was not altered in the presence of PTB4 or PTB2. Mutational analysis reveals that stimulation of MMTV-IRES activity is abrogated when PTB1 is mutated either in RRM1/RRM2 or RRM3/RRM4. In contrast, a PTB4 RRM1/RRM2 mutant has reduced effect over MMTV-IRES activity, while stimulation of the MMTV-IRES activity is still observed when the PTB4 RRM3/RMM4 mutant is used. Therefore, PTB1 and PTB4 differentially stimulate the IRES activity. In contrast, PTB2 acts as a negative modulator of PTB4-induced stimulation of MMTV-IRES. We conclude that PTB1 and PTB4 act as IRES trans-acting factors of the MMTV-IRES. CI - (c) 2016 Federation of European Biochemical Societies. FAU - Caceres, Carlos J AU - Caceres CJ AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. FAU - Contreras, Nataly AU - Contreras N AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. FAU - Angulo, Jenniffer AU - Angulo J AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. FAU - Vera-Otarola, Jorge AU - Vera-Otarola J AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. FAU - Pino-Ajenjo, Constanza AU - Pino-Ajenjo C AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. FAU - Llorian, Miriam AU - Llorian M AD - Department of Biochemistry, University of Cambridge, UK. FAU - Ameur, Melissa AU - Ameur M AD - Centre national de la Recherche Scientifique, Unite Mixte de Recherche 8015, Laboratoire de Cristallographie et RMN Biologique, Universite Paris Descartes, France. FAU - Lisboa, Francisco AU - Lisboa F AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. FAU - Pino, Karla AU - Pino K AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. FAU - Lowy, Fernando AU - Lowy F AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. FAU - Sargueil, Bruno AU - Sargueil B AD - Centre national de la Recherche Scientifique, Unite Mixte de Recherche 8015, Laboratoire de Cristallographie et RMN Biologique, Universite Paris Descartes, France. FAU - Lopez-Lastra, Marcelo AU - Lopez-Lastra M AD - Laboratorio de Virologia Molecular, Instituto Milenio de Inmunologia e Inmunoterapia, Centro de Investigaciones Medicas, Departamento de Enfermedades Infecciosas e Inmunologia Pediatrica, Escuela de Medicina, Pontificia Universidad Catolica de Chile, Santiago, Chile. LA - eng GR - 092900/Wellcome Trust/United Kingdom PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20160405 PL - England TA - FEBS J JT - The FEBS journal JID - 101229646 RN - 0 (5' Untranslated Regions) RN - 0 (Internal Ribosome Entry Sites) RN - 0 (RNA Caps) RN - 0 (RNA, Messenger) RN - 139076-35-0 (Polypyrimidine Tract-Binding Protein) SB - IM MH - *5' Untranslated Regions MH - Binding Sites MH - Gene Knockdown Techniques MH - Genes, Viral MH - HEK293 Cells MH - Humans MH - Internal Ribosome Entry Sites MH - Mammary Tumor Virus, Mouse/*genetics MH - Polypyrimidine Tract-Binding Protein/genetics/*metabolism MH - *RNA Caps MH - RNA, Messenger/*genetics OTO - NOTNLM OT - IRES trans-acting factor OT - internal ribosomal entry site OT - mouse mammary tumor virus OT - polypyrimidine tract-binding protein EDAT- 2016/03/15 06:00 MHDA- 2017/06/01 06:00 CRDT- 2016/03/15 06:00 PHST- 2016/01/21 00:00 [received] PHST- 2016/03/01 00:00 [revised] PHST- 2016/03/08 00:00 [accepted] PHST- 2016/03/15 06:00 [entrez] PHST- 2016/03/15 06:00 [pubmed] PHST- 2017/06/01 06:00 [medline] AID - 10.1111/febs.13708 [doi] PST - ppublish SO - FEBS J. 2016 May;283(10):1880-901. doi: 10.1111/febs.13708. Epub 2016 Apr 5.