HOXA9 regulates miR-155 in hematopoietic cells |
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Authors: | Yu-Long Hu Stephen Fong Corey Largman Wei-Fang Shen |
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Affiliation: | Department of Medicine, Department of Veterans Affairs Medical Center and University of California, San Francisco, CA 94143, USA |
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Abstract: | HOXA9-mediated up-regulation of miR-155 was noted during an array-based analysis of microRNA expression in Hoxa9−/−bone marrow (BM) cells. HOXA9 induction of miR-155 was confirmed in these samples, as well as in wild-type versus Hoxa9-deficient marrow, using northern analysis and qRT–PCR. Infection of wild-type BM with HOXA9 expressing or GFP+ control virus further confirmed HOXA9-mediated regulation of miR-155. miR-155 expression paralleled Hoxa9 mRNA expression in fractionated BM progenitors, being highest in the stem cell enriched pools. HOXA9 capacity to induce myeloid colony formation was blunted in miR-155-deficient BM cells, indicating that miR-155 is a downstream mediator of HOXA9 function in blood cells. Pu.1, an important regulator of myelopoiesis, was identified as a putative down stream target for miR-155. Although miR-155 was shown to down-regulate the Pu.1 protein, HOXA9 did not appear to modulate Pu.1 expression in murine BM cells. |
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