title: JAK2 exon 14 skipping in patients with primary myelofibrosis: a minor splice variant modulated by the JAK2-V617F allele burden.
abstract: BACKGROUND
  Primary myelofibrosis (PMF) is an acquired clonal disease of the hematopoietic stem cell compartment, characterized by bone marrow fibrosis, anemia, splenomegaly and extramedullary hematopoiesis. About 60% of patients with PMF harbor a somatic mutation of the JAK2 gene (JAK2-V617F) in their hematopoietic lineage. Recently, a splicing isoform of JAK2, lacking exon 14 (JAK2Δ14) was described in patients affected by myeloproliferative diseases.
  
  
  METHODS
  By using a specific RT-qPCR method, we measured the ratio between the splicing isoform and the JAK2 full-length transcript (JAK2+14) in granulocytes, isolated from peripheral blood, of forty-four patients with PMF and nine healthy donors.
  
  
  RESULTS
  We found that JAK2Δ14 was only slightly increased in patients and, at variance with published data, the splicing isoform was also detectable in healthy controls. We also found that, in patients bearing the JAK2-V617F mutation, the percentage of mutated alleles correlated with the observed increase in JAK2Δ14. Homozygosity for the mutation was also associated with a higher level of JAK2+14. Bioinformatic analysis indicates the possibility that the G>T transversion may interfere with the correct splicing of exon 14 by modifying a splicing regulatory sequence.
  
  
  CONCLUSIONS
  Increased levels of JAK2 full-length transcript and a small but significant increase in JAK2 exon 14 skipping, are associated with the JAK2-V617F allele burden in PMF granulocytes. Our data do not confirm a previous claim that the production of the JAK2Δ14 isoform is related to the pathogenesis of PMF.
authors.affiliation: Center for the Study and Treatment of Myelofibrosis, Biotechnology Research Laboratories, Fondazione IRCCS "Policlinico San Matteo", Pavia (PV), Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Catarsi
authors.affiliation: Center for the Study and Treatment of Myelofibrosis, Biotechnology Research Laboratories, Fondazione IRCCS "Policlinico San Matteo", Pavia (PV), Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Rosti
authors.affiliation: Viticulture Research Center, Consiglio per la Ricerca e la sperimentazione in Agricoltura, Conegliano (TV), Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Morreale
authors.affiliation: Center for the Study and Treatment of Myelofibrosis, Biotechnology Research Laboratories, Fondazione IRCCS "Policlinico San Matteo", Pavia (PV), Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Poletto
authors.affiliation: Center for the Study and Treatment of Myelofibrosis, Biotechnology Research Laboratories, Fondazione IRCCS "Policlinico San Matteo", Pavia (PV), Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Villani
authors.affiliation: Laboratory of Biomolecular Sequence and Structure Analysis for Health, Fondazione "Bruno Kessler", Trento (TN), Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Bertorelli
authors.affiliation: Cardiovascular Genetics Laboratory, Biomedical and Technology Research Centre, Istituto Auxologico Italiano, Cusano Milanino (MI), Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Pedrazzini
authors.affiliation: Laboratory of Biochemistry and Genetics, Division of Pneumology, Department of Molecular Medicine, Fondazione IRCCS "Policlinico San Matteo", Pavia (PV), Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Zorzetto
authors.affiliation: Center for the Study and Treatment of Myelofibrosis, Biotechnology Research Laboratories, Fondazione IRCCS "Policlinico San Matteo", Pavia (PV), Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Barosi
mesh_terms: D002460:Cell Line; D019295:Computational Biology; D005091:Exons; D020869:Gene Expression Profiling; D006801:Humans; D053614:Janus Kinase 2 / Q000737:chemistry / Q000235:genetics*; D009154:Mutation; D055728:Primary Myelofibrosis / Q000235:genetics*; D012326:RNA Splicing; D012044:Regression Analysis; D017384:Sequence Deletion
chemical_list: C507924:JAK2 protein, human; D053614:Janus Kinase 2