JAK2 exon 14 skipping in patients with primary myelofibrosis: A minor splice variant modulated by the JAK2-V617F allele burden

Paolo Catarsi, Vittorio Rosti, Giacomo Morreale, Valentina Poletto, Laura Villani, Roberto Bertorelli, Matteo Pedrazzini, Michele Zorzetto, Giovanni Barosi

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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. Materials and 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, 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.

Original languageEnglish
Article numbere0116636
JournalPLoS One
Volume10
Issue number1
DOIs
Publication statusPublished - Jan 24 2015

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ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

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