Embryologic studies have shown that extrinsic signals produced by non-hematopoietic tissues are required for blood development, but the identity of the signaling molecule (s) that transmit this information are unknown. We have shown that Bone morphogenetic protein (BMP) function is required in ectodermal cells to generate a secondary signal (s) that act across gem layers to enable blood progenitors to commit to the erythroid pathway and to protect pathways from apoptosis. Furthermore, calmodulin-dependent kinase IV (CaM KIV) is required to negatively regulate BMP mediated transcriptional responses during hematopoiesis. Our data support a model in which CaM KIV inhibits BMP signaling by activating a substrate that binds to CREB binding protein (CBP). This binding disrupts interactions between limiting amounts of CBP and an unidentified hematopoietic-specific DNA binding protein that functions in concert with BMP-specific transcription factors. Preliminary data suggest that this DNA binding protein is GATA-2. We will test this hypothesis and will begin to identify intrinsic factors that signal downstream of this transcription factor network by completing the following aims: 1. Preliminary data show that loss of GATA-2 in ectodermal cells of Xenopus embryos phenocopies hematopoietic defects caused by misregulation of BMP activity. We will use epistasis and biochemical analysis to determine whether these function in the same or parallel pathways. 2. We have identified stem cell factor as an ectodermally derived cytokine that is required for blood formation and have used a microarray approach to identify genes that may be transcriptionally regulated by BMP/ CaM KIV signals in ectodermal cells. We will use quantitative approaches to validate these targets and will begin to test their function in blood development in Xenopus embryos as time allows. The proposed studies will set the stage for further analysis of interactions between BMP/CamKIV and GATA-2 in transcriptional regulation of extrinsic signals required for blood development. In addition, we will identify novel components of the blood development cascade for future studies. Understanding how normal blood development occurs is crucial to understanding and preventing disease resulting from misregulation of these pathways.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Small Research Grants (R03)
Project #
1R03HD050242-01
Application #
6956109
Study Section
Pediatrics Subcommittee (CHHD)
Program Officer
Coulombe, James N
Project Start
2005-07-01
Project End
2007-06-30
Budget Start
2005-07-01
Budget End
2006-06-30
Support Year
1
Fiscal Year
2005
Total Cost
$76,250
Indirect Cost
Name
Oregon Health and Science University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
096997515
City
Portland
State
OR
Country
United States
Zip Code
97239
Green, Yangsook Song; Kwon, Sunjong; Christian, Jan L (2016) Expression pattern of bcar3, a downstream target of Gata2, and its binding partner, bcar1, during Xenopus development. Gene Expr Patterns 20:55-62
Green, Yangsook Song; Kwon, Sunjong; Mimoto, Mizuho S et al. (2016) Tril targets Smad7 for degradation to allow hematopoietic specification in Xenopus embryos. Development 143:4016-4026
Mimoto, Mizuho S; Kwon, Sunjong; Green, Yangsook Song et al. (2015) GATA2 regulates Wnt signaling to promote primitive red blood cell fate. Dev Biol 407:1-11
Mimoto, Mizuho S; Christian, Jan L (2012) Friend of GATA (FOG) interacts with the nucleosome remodeling and deacetylase complex (NuRD) to support primitive erythropoiesis in Xenopus laevis. PLoS One 7:e29882
Goldman, Devorah C; Bailey, Alexis S; Pfaffle, Dana L et al. (2009) BMP4 regulates the hematopoietic stem cell niche. Blood 114:4393-401
Dalgin, Gokhan; Goldman, Devorah C; Donley, Nathan et al. (2007) GATA-2 functions downstream of BMPs and CaM KIV in ectodermal cells during primitive hematopoiesis. Dev Biol 310:454-69
Goldman, Devorah C; Berg, Linnea K; Heinrich, Michael C et al. (2006) Ectodermally derived steel/stem cell factor functions non-cell autonomously during primitive erythropoiesis in Xenopus. Blood 107:3114-21