Direct Reprogramming of Fibroblasts into Neural Stem Cells by Defined Factors
CELL STEM CELL
Authors: Han, Dong Wook; Tapia, Natalia; Hermann, Andreas; Hemmer, Kathrin; Hoeing, Susanne; Arauzo-Bravo, Marcos J.; Zaehres, Holm; Wu, Guangming; Frank, Stefan; Moritz, Soeren; Greber, Boris; Yang, Ji Hun; Lee, Hoon Taek; Schwamborn, Jens C.; Storch, Alexander; Schoeler, Hans R.
Abstract
Recent studies have shown that defined sets of transcription factors can directly reprogram differentiated somatic cells to a different differentiated cell type without passing through a pluripotent state, but the restricted proliferative and lineage potential of the resulting cells limits the scope of their potential applications. Here we show that a combination of transcription factors (Brn4/Pou3f4, Sox2, Klf4, c-Myc, plus E47/Tcf3) induces mouse fibroblasts to directly acquire a neural stem cell identity which we term as induced neural stem cells (iNSCs). Direct reprogramming of fibroblasts into iNSCs is a gradual process in which the donor transcriptional program is silenced over time. iNSCs exhibit cell morphology, gene expression, epigenetic features, differentiation potential, and self-renewing capacity, as well as in vitro and in vivo functionality similar to those of wild-type NSCs. We conclude that differentiated cells can be reprogrammed directly into specific somatic stem cell types by defined sets of specific transcription factors.
A novel TCF3-HLF fusion transcript in acute lymphoblastic leukemia with a t(17;19)(q22;p13)
CANCER GENETICS
Authors: Panagopoulos, Ioannis; Micci, Francesca; Thorsen, Jim; Haugom, Lisbeth; Tierens, Anne; Ulvmoen, Aina; Heim, Sverre
Abstract
A 10-year-old boy was admitted to the hospital because of anemia detected after a two week history of fatigue, dizziness, nausea, headaches, and weight loss. A bone marrow investigation confirmed a diagnosis of acute lymphoblastic leukemia of the B-cell precursor phenotype. Chromosome G-banding analysis yielded the karyotype 46,XY,t(17;19)(q22;p13), and fluorescence in situ hybridization (FISH) analysis showed rearrangement of the genes TCF3 (on 19p13; accession number NM_03200 version 3) and HLF (on 17q22; accession number NM_002126 version 4) with the generation of a TCF3-HLF chimera. Polymerase chain reaction and sequencing analyses demonstrated the presence of two in-frame chimeric TCF3-HLF transcripts. In the first one, which corresponds to a type 2 fusion, exon 15 of TCF3 is fused to exon 4 of HLF. In the second, described here for the first time and named type 3, exon 14 of TCF3 is fused to exon 4 of HLF. Whether the type 3 chimeric transcript has the same DNA binding and transcriptional regulatory effect as type 1 and type 2 TCF3-HLF chimeras remains to be seen.