title: Aberrant eukaryotic translation initiation factor 4E-dependent mRNA transport impedes hematopoietic differentiation and contributes to leukemogenesis.
abstract: The eukaryotic translation initiation factor 4E (eIF4E) acts as both a key translation factor and as a promoter of nucleocytoplasmic transport of specific transcripts. Traditionally, its transformation capacity in vivo is attributed to its role in translation initiation in the cytoplasm. Here, we demonstrate that elevated eIF4E impedes granulocytic and monocytic differentiation. Our subsequent mutagenesis studies indicate that this block is a result of dysregulated eIF4E-dependent mRNA transport. These studies indicate that the RNA transport function of eIF4E could contribute to leukemogenesis. We extended our studies to provide the first evidence that the nuclear transport function of eIF4E contributes to human malignancy, specifically in a subset of acute and chronic myelogenous leukemia patients. We observe an increase in eIF4E-dependent cyclin D1 mRNA transport and a concomitant increase in cyclin D1 protein levels. The aberrant nuclear function of eIF4E is due to abnormally large eIF4E bodies and the loss of regulation by the proline-rich homeodomain PRH. We developed a novel tool to modulate this transport activity. The introduction of IkappaB, the repressor of NF-kappaB, leads to suppression of eIF4E, elevation of PRH, reorganization of eIF4E nuclear bodies, and subsequent downregulation of eIF4E-dependent mRNA transport. Thus, our findings indicate that this nuclear function of eIF4E can contribute to leukemogenesis by promoting growth and by impeding differentiation.
authors.affiliation: Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, New York University, One Gustave Levy Place, New York, NY 10029, USA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Topisirovic
authors.forename: Monica L
authors.initials: ML
authors.lastname: Guzman
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: McConnell
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Licht
authors.forename: Biljana
authors.initials: B
authors.lastname: Culjkovic
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Neering
authors.forename: Craig T
authors.initials: CT
authors.lastname: Jordan
authors.forename: Katherine L B
authors.initials: KL
authors.lastname: Borden
mesh_terms: D021581:Active Transport, Cell Nucleus; D001483:Base Sequence; D002454:Cell Differentiation; D019938:Cyclin D1 / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D039561:Eukaryotic Initiation Factor-4E / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc; D006410:Hematopoiesis / Q000235:genetics / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007938:Leukemia / Q000209:etiology* / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors
chemical_list: D018076:DNA, Complementary; D004273:DNA, Neoplasm; D039561:Eukaryotic Initiation Factor-4E; C078492:HHEX protein, human; D018398:Homeodomain Proteins; D016328:NF-kappa B; D012333:RNA, Messenger; D014157:Transcription Factors; D019938:Cyclin D1