Downstream targets of HOXB4 in a cell line model of primitive hematopoietic progenitor cells

• Published in: Blood Vol. 116; no. 5; pp. 720 - 730
• Main Authors: Lee, Han M., Zhang, Hui, Schulz, Vincent, Tuck, David P., Forget, Bernard G.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 05-08-2010; Americain Society of Hematology; American Society of Hematology
• Series: Hematopoiesis and Stem Cells
• Subjects: Animals; Apoptosis - genetics; Biological and medical sciences; Cell Division; Cell Line, Transformed; Cell Lineage; Chromatin Immunoprecipitation; Clone Cells - cytology; Gene Expression Profiling; Gene Expression Regulation; Genes, Reporter; Hematologic and hematopoietic diseases; Hematopoiesis and Stem Cells; Hematopoietic Stem Cells - cytology; Homeodomain Proteins - genetics; Homeodomain Proteins - physiology; Leukocyte Common Antigens - biosynthesis; Leukocyte Common Antigens - genetics; Medical sciences; Mice; Myelopoiesis - genetics; Promoter Regions, Genetic - genetics; Recombinant Fusion Proteins - physiology; RNA, Messenger - biosynthesis; RNA, Messenger - genetics; Transcription Factors - genetics; Transcription Factors - physiology; Transcription, Genetic; Transduction, Genetic; Primitive; Hematology; Stem cell; Established cell line; Hematopoietic cell; Models; Target cell
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2009-11-253872

Enforced expression of the homeobox transcription factor HOXB4 has been shown to enhance hematopoietic stem cell self-renewal and expansion ex vivo and in vivo. To investigate the downstream targets of HOXB4 in hematopoietic progenitor cells, HOXB4 was constitutively overexpressed in the primitive hematopoietic progenitor cell line EML. Two genome-wide analytical techniques were used: RNA expression profiling using microarrays and chromatin immunoprecipitation (ChIP)–chip. RNA expression profiling revealed that 465 gene transcripts were differentially expressed in KLS (c-Kit+, Lin−, Sca-1+)-EML cells that overexpressed HOXB4 (KLS-EML-HOXB4) compared with control KLS-EML cells that were transduced with vector alone. In particular, erythroid-specific gene transcripts were observed to be highly down-regulated in KLS-EML-HOXB4 cells. ChIP-chip analysis revealed that the promoter region for 1910 genes, such as CD34, Sox4, and B220, were occupied by HOXB4 in KLS-EML-HOXB4 cells. Side-by-side comparison of the ChIP-chip and RNA expression profiling datasets provided correlative information and identified Gp49a and Laptm4b as candidate “stemness-related” genes. Both genes were highly ranked in both dataset lists and have been previously shown to be preferentially expressed in hematopoietic stem cells and down-regulated in mature hematopoietic cells, thus making them attractive candidates for future functional studies in hematopoietic cells.