Hemoglobin production is an evolutionarily conserved process that is specific to the red blood cell lineage. We have utilized the zebrafish as a model for studying this process. Our analysis of mutant fish with a hypochromic microcytic anemia has provided key insights into factors that regulate hemoglobin synthesis. These factors fall into four categories: the production of heme, iron utilization, globin expression, and iron sulfur cluster production. We have found several novel genes involved in hemoglobin production, including ferroportin, mitoferrin, and glutaredoxin 5. The first two of these factors were found to be mutated in patients with human disorders, establishing the zebrafish system as a model for human disease. To date, we have uncovered over eight complementation groups of hypochromic anemia. In this proposal, we plan to extend our observations by characterizing the globin locus of the zebrafish, including its associated chromatin structure. Regulatory elements will also be examined. The zebrafish locus control region (LCR) is representative of an ?LCR. In transgenics, bringing the zebrafish LCR into apposition with globin genes drives high level of expression within erythroid cells. Transgenic fish are being created with human globin BACs to evaluate conservation of regulatory elements. The mutant zinfandel lacks embryonic globin production, but recovers and has normal adult hemoglobin formation. This gene was mapped to the globin locus on chromosome 3 and no globin coding regions are mutated. A high-resolution positional cloning project is underway to define this novel embryonic-specific globin regulatory mutation. We also developed a method for genetically analyzing chromatin factors that regulate hemoglobin production. The technology of morpholinos in which antisense oligonucleotides against specific genes are injected into the one cell embryo can knock-down gene function and will reveal changes in erythropoiesis. A compendium of over 300 chromatin remodeling factors that are orthologs of human genes has been created, and each will be studied by gene knock-down in zebrafish embryos. The effect of gene knock-down on erythroid gene expression (including LCR activation and globin gene expression) will be evaluated. These factors will be studied genetically in the zebrafish and interactions with specific transcription factors will be investigated by double knock-down and overexpression studies. Using human erythroid cells, we plan to biochemically purify a complex of chromatin factor orthologs found through this genetic screen. The understanding of chromatin factors that affect hemoglobin production will have a tremendous impact on our understanding of hemoglobin production and for the treatment of patients with thalassemia, sickle cell anemia, and globin mutations.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK053298-15
Application #
8214628
Study Section
Erythrocyte and Leukocyte Biology Study Section (ELB)
Program Officer
Bishop, Terry Rogers
Project Start
1998-02-01
Project End
2014-01-31
Budget Start
2012-02-01
Budget End
2014-01-31
Support Year
15
Fiscal Year
2012
Total Cost
$351,978
Indirect Cost
$143,707
Name
Children's Hospital Boston
Department
Type
DUNS #
076593722
City
Boston
State
MA
Country
United States
Zip Code
02115
Rost, Megan S; Shestopalov, Ilya; Liu, Yang et al. (2018) Nfe2 is dispensable for early but required for adult thrombocyte formation and function in zebrafish. Blood Adv 2:3418-3427
Mandelbaum, Joseph; Shestopalov, Ilya A; Henderson, Rachel E et al. (2018) Zebrafish blastomere screen identifies retinoic acid suppression of MYB in adenoid cystic carcinoma. J Exp Med 215:2673-2685
Kapp, Friedrich G; Perlin, Julie R; Hagedorn, Elliott J et al. (2018) Protection from UV light is an evolutionarily conserved feature of the haematopoietic niche. Nature 558:445-448
Blaser, Bradley W; Zon, Leonard I (2018) Making HSCs in vitro: don't forget the hemogenic endothelium. Blood 132:1372-1378
Perlin, Julie R; Robertson, Anne L; Zon, Leonard I (2017) Efforts to enhance blood stem cell engraftment: Recent insights from zebrafish hematopoiesis. J Exp Med 214:2817-2827
Wiley, D S; Redfield, S E; Zon, L I (2017) Chemical screening in zebrafish for novel biological and therapeutic discovery. Methods Cell Biol 138:651-679
Perlin, Julie R; Sporrij, Audrey; Zon, Leonard I (2017) Blood on the tracks: hematopoietic stem cell-endothelial cell interactions in homing and engraftment. J Mol Med (Berl) 95:809-819
Henninger, Jonathan; Santoso, Buyung; Hans, Stefan et al. (2017) Clonal fate mapping quantifies the number of haematopoietic stem cells that arise during development. Nat Cell Biol 19:17-27
Theodore, Lindsay N; Hagedorn, Elliott J; Cortes, Mauricio et al. (2017) Distinct Roles for Matrix Metalloproteinases 2 and 9 in Embryonic Hematopoietic Stem Cell Emergence, Migration, and Niche Colonization. Stem Cell Reports 8:1226-1241
Choudhuri, Avik; Fast, Eva M; Zon, Leonard I (2017) Using Zebrafish to Study Pathways that Regulate Hematopoietic Stem Cell Self-Renewal and Migration. Stem Cell Reports 8:1465-1471

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