Determining c-Myb Protein Levels Can Isolate Functional Hematopoietic Stem Cell Subtypes. (22nd January 2015)

• Record Type: Journal Article
• Authors: Sakamoto, Hiroshi; Takeda, Naoki; Arai, Fumio; Hosokawa, Kentaro; Garcia, Paloma; Suda, Toshio; Frampton, Jon; Ogawa, Minetaro
• Is Part Of: Stem cells. Volume 33:Number 2(2015:Feb.)
• Page Start: 479
• Page End: 490
• Publication Date: 2015-01-22
• Subjects: Hematopoietic stem cells -- Proto-oncogene proteins c-myb -- Animals -- Genetically modified -- Hematopoietic stem cell transplantation -- Cell proliferation -- Hematopoiesis; Cloning -- Periodicals; Clone cells -- Periodicals; Stem cells -- Periodicals; Cell Differentiation -- Periodicals; Cell Division -- Periodicals; Clone Cells -- Periodicals; Hematopoietic Stem Cells -- Periodicals; Stem Cells -- Periodicals; 571.84
• DOI: 10.1002/stem.1855
• Languages: English
• ISSNs: 1066-5099

Abstract

Abstract: The transcription factor c-Myb was originally identified as a transforming oncoprotein encoded by two avian leukemia viruses. Subsequently, through the generation of mouse models that affect its expression, c-Myb has been shown to be a key regulator of hematopoiesis, including having critical roles in hematopoietic stem cells (HSCs). The precise function of c-Myb in HSCs although remains unclear. We have generated a novel c-myb allele in mice that allows direct observation of c-Myb protein levels in single cells. Using this reporter line we demonstrate that subtypes of HSCs can be isolated based upon their respective c-Myb protein expression levels. HSCs expressing low levels of c-Myb protein (c-Myb low HSC) appear to represent the most immature, dormant HSCs and they are a predominant component of HSCs that retain bromodeoxyuridine labeling. Hematopoietic stress, induced by 5-fluorouracil ablation, revealed that in this circumstance c-Myb-expressing cells become critical for multilineage repopulation. The discrimination of HSC subpopulations based on c-Myb protein levels is not reflected in the levels of c-myb mRNA, there being no more than a 1.3-fold difference comparing c-Myb low and c-Myb high HSCs. This illustrates how essential it is to include protein studies when aiming to understand the regulatory networks that control stem cell behavior. Stem Cells 2015;33:479–490