The objectives of this proposal are to identify and characterize novel proteins involved in mitochondrial iron/heme metabolism identified from differentiating fetal liver population by mRNA sequencing (RNAseq) and bioinformatics approaches. Heme serves as a prosthetic group in hemo-proteins for a wide array of crucial cellular processes, and of these, hemoglobin synthesis in red cells is the most well known. Despite advances in our understanding of cytosolic iron trafficking and proto-prophyrin biosynthesis, significant gaps remain, especially, with respect to components involving the egress of iron from the endosomes to the mitochondria, the trafficking of iron/heme within the mitochondria, and the eventual export of heme from the mitochondria for its incorporation in hemoglobin. In recent years, we have characterized the role ofthe l /litoferrin1 (l /lfrn1, Slc25a37) iron importer and its interaction with other mitochondrial proteins, AbcblO and ferrochelatase, in the acquisition of mitochondrial iron and its utilization in heme synthesis. In an attempt to dentify additional, unknown components important for heme synthesis, we screened thousands of microarrays for genes that were tightly co-expressed and co-regulated with previously known heme biosynthesis genes to identify potentially interesting, novel candidate genes. Follow up studies of these candidate genes in the zebrafish showed that gene-specific knockdown, using anti-sense morpholinos, resulted in profound anemia in all cases. In a complementary approach, we recently analyzed the expression of structural proteins with predicted transmembrane motifs, transporter function, or localization to the mitochondria, which were identified by RNAseq analysis from differentiating fetal liver cells. We identified 9 additional strongly induced genes, whose function in erythroid iron/heme metabolism has not been previously studied. We propose to study the expression and loss-of-function phenotype of these 9 structural genes (c20orf108, Snx3, Slc43a1, Slc43a3, Slc7a5, Ehbplll, Tmcc2, Slc38a5, Tmem14c) in the zebrafish and mammalian cells. In particular, we plan to focus on one of these newly identified genes from the two bioinformatics screens, Tmem14c, a small mitochondrial membrane protein of unknown function.

Public Health Relevance

Elucidating the function of these 8 structural proteins, Tmem14c and its interacting protein partners may give insight into unknown steps in mitochondrial heme metabolism and provide new genetic tools for exploring human disorders of iron/heme metabolism and erythropoiesis.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Program Projects (P01)
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Heart, Lung, and Blood Initial Review Group (HLBP)
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Children's Hospital Boston
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Chung, Jacky; Wittig, Johannes G; Ghamari, Alireza et al. (2017) Erythropoietin signaling regulates heme biosynthesis. Elife 6:
Kafina, Martin D; Paw, Barry H (2017) Intracellular iron and heme trafficking and metabolism in developing erythroblasts. Metallomics 9:1193-1203
Doulatov, Sergei; Vo, Linda T; Macari, Elizabeth R et al. (2017) Drug discovery for Diamond-Blackfan anemia using reprogrammed hematopoietic progenitors. Sci Transl Med 9:
Seguin, Alexandra; Takahashi-Makise, Naoko; Yien, Yvette Y et al. (2017) Reductions in the mitochondrial ABC transporter Abcb10 affect the transcriptional profile of heme biosynthesis genes. J Biol Chem 292:16284-16299
Grillo, Anthony S; SantaMaria, Anna M; Kafina, Martin D et al. (2017) Restored iron transport by a small molecule promotes absorption and hemoglobinization in animals. Science 356:608-616
Yien, Yvette Y; Ducamp, Sarah; van der Vorm, Lisa N et al. (2017) Mutation in human CLPX elevates levels of ?-aminolevulinate synthase and protoporphyrin IX to promote erythropoietic protoporphyria. Proc Natl Acad Sci U S A 114:E8045-E8052
Gao, Xiaofei; Lee, Hsiang-Ying; Li, Wenbo et al. (2017) Thyroid hormone receptor beta and NCOA4 regulate terminal erythrocyte differentiation. Proc Natl Acad Sci U S A 114:10107-10112
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
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
van Rooij, Frank J A; Qayyum, Rehan; Smith, Albert V et al. (2017) Genome-wide Trans-ethnic Meta-analysis Identifies Seven Genetic Loci Influencing Erythrocyte Traits and a Role for RBPMS in Erythropoiesis. Am J Hum Genet 100:51-63

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