The goal of this application is to understand how trans-acting factors and coregulators function through the beta-globin locus control region (LCR) to confer strong transcription to the beta-globin genes over a long distance on a chromosome. We discovered that RNA polymerase II (pol II) resides at the LCR in erythroid cells and formulated a new model of LCR function called long-range pol II transfer (LPT). This model proposes that LCR-bound pol II relocalizes to beta-globin promoters in a regulated fashion, thereby constituting a critical step in activation. The following Specific Aims will address how pol II is recruited to the LCR and the resulting functional consequences.
Aim 1. To define the role of GATA-1 and Friend of GATA-1 (FOG-l) in pol II recruitment to the LCR. Pol II associates with the LCR in erythroid cells, and GATA-1 induces pol II recruitment. We hypothesize that GATA-1 functions with other factors to recruit pol II. GATA-I-null cells will be used to define how GATA-1 recruits pol II. Cells lacking the GATA-1 coregulator FOG-1 will be used to define if FOG-1 is required. Experiments will address whether single hypersensitive sites autonomously recruit pol II.
Aim 2. To determine if pol II recruitment to the LCR is dynamic during erythropoiesis. As the concentrations and activities of erythroid-specific factors change during erythropoiesis, we hypothesize that pol II loading on the LCR is developmentally dynamic. Experiments will assess if pol II recruitment to the LCR differs between embryonic and adult erythroid cells.
Aim 3. To discriminate among models for understanding the function of pol II at the LCR. Besides LPT, LCR-bound pol II might engage in transcription-dependent chromatin remodeling or the generation of regulatory transcripts. Experiments will discriminate among models to explain the function of pol II at the LCR. These studies will increase our understanding of how the LCR regulates the beta-globin genes, which should have broad relevance to mechanisms controlling diverse cellular and organismal processes. The long-term objective is to therapeutically control beta-globin genes in humans with hemoglobinopathies by regulating specific steps of the LCR mechanism.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK055700-05
Application #
6619970
Study Section
Hematology Subcommittee 2 (HEM)
Program Officer
Badman, David G
Project Start
1999-05-01
Project End
2007-02-28
Budget Start
2003-05-01
Budget End
2004-02-29
Support Year
5
Fiscal Year
2003
Total Cost
$285,087
Indirect Cost
Name
University of Wisconsin Madison
Department
Pharmacology
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
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Kim, S-I; Bresnick, E H (2007) Transcriptional control of erythropoiesis: emerging mechanisms and principles. Oncogene 26:6777-94
Johnson, Kirby D; Boyer, Meghan E; Kang, Jeong-Ah et al. (2007) Friend of GATA-1-independent transcriptional repression: a novel mode of GATA-1 function. Blood 109:5230-3
Kim, Shin-Il; Bultman, Scott J; Jing, Huie et al. (2007) Dissecting molecular steps in chromatin domain activation during hematopoietic differentiation. Mol Cell Biol 27:4551-65
Martowicz, Melissa L; Grass, Jeffrey A; Bresnick, Emery H (2006) GATA-1-mediated transcriptional repression yields persistent transcription factor IIB-chromatin complexes. J Biol Chem 281:37345-52
Johnson, Kirby D; Kim, Shin-Il; Bresnick, Emery H (2006) Differential sensitivities of transcription factor target genes underlie cell type-specific gene expression profiles. Proc Natl Acad Sci U S A 103:15939-44
Bresnick, Emery H; Johnson, Kirby D; Kim, Shin-Il et al. (2006) Establishment and regulation of chromatin domains: mechanistic insights from studies of hemoglobin synthesis. Prog Nucleic Acid Res Mol Biol 81:435-71
Bresnick, Emery H; Martowicz, Melissa L; Pal, Saumen et al. (2005) Developmental control via GATA factor interplay at chromatin domains. J Cell Physiol 205:1-9
Im, Hogune; Grass, Jeffrey A; Johnson, Kirby D et al. (2005) Chromatin domain activation via GATA-1 utilization of a small subset of dispersed GATA motifs within a broad chromosomal region. Proc Natl Acad Sci U S A 102:17065-70
Pal, Saumen; Nemeth, Michael J; Bodine, David et al. (2004) Neurokinin-B transcription in erythroid cells: direct activation by the hematopoietic transcription factor GATA-1. J Biol Chem 279:31348-56

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