MPLW515L Is a Novel Somatic Activating Mutation in Myelofibrosis with Myeloid Metaplasia (original) (raw)
Figure 1
MPLW515L Mutation Is Found in JAK2V617F-Negative MF and Causes Cytokine-Independent Growth in 32D and UT7 Cells, and Constitutively Activates the JAK-STAT Signaling Pathway
(A) Forward (middle trace) and reverse (lower trace) sequence traces demonstrating a heterozygous guanine to thymine substitution (arrows) present in granulocyte DNA from a patient with MF. The mutation is not present in buccal DNA from the same patient (upper trace).
(B) DNA sequence and protein translation for both the wild-type and mutant MPL alleles. The mutation results in a tryptophan-to-leucine substitution at codon 515.
(C) Upper: 32D cells transduced with MPLW515L exhibit cytokine-independent growth compared with MPLWT (left). Cell lines grown in the presence of IL3 show equal rates of growth (right). Error bars denote the standard deviation for each sample measured in triplicate. Lower: UT7 cells transformed with MPLW515L exhibit cytokine-independent growth compared with MPLWT (left). Cell lines grown in the presence of TPO (5 ng/mL) show equal rates of growth (right). Error bars denote the standard deviation for each sample measured in triplicate.
(D) 32D cells, 32D MPLWT cells, and 32D MPLW515L cells were deprived of cytokines and then analyzed by Western blots, demonstrating phosphorylation of JAK2, STAT5, STAT3, AKT, and ERK in MPLW515L compared with MPLWT.