Characterization of the heme synthesis enzyme coproporphyrinogen oxidase (CPO) in zebrafish erythrogenesis.
Hemoglobin consists of heme and globin proteins and is essential for oxygen transport in all vertebrates. Although biochemical features of heme synthesis enzymes have been well characterized, the function of these enzymes in early embryogenesis is not fully understood. We found that the sixth heme synthesis enzyme, coproporphyrinogen oxidase (CPO), is predominantly expressed in the intermediate cell mass (ICM) that is a major site of zebrafish primitive hematopoiesis. Knockdown of zebrafish CPO using anti-sense morpholinos (CPO-MO) leads to a significant suppression of hemoglobin production without apparent reduction of blood cells. Injection of human CPO RNA, but not a mutant CPO RNA that is similar to a mutant responsible for a hereditary coproporphyria (HCP), restores hemoglobin production in the CPO-MO-injected embryos. Furthermore, expression of CPO in the ICM is severely suppressed in both vlad tepes/gata1 mutants and in biklf-MO-injected embryos. In contrast, over-expression of biklf and gata1 significantly induces ectopic CPO expression. The function of CPO in heme biosynthesis is apparently conserved between zebrafish and human, suggesting that CPO-MO-injected zebrafish embryos might be a useful in vivo assay system to measure the biological activity of human CPO mutations.
Laboratory of Developmental Molecular Genetics, Horizontal Medical Research Organization, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-Ku, Kyoto, 606-8501, Japan.
Ryuki
R
Hanaoka
Shiori
S
Katayama
Igor B
IB
Dawid
Atsuo
A
Kawahara
D000595:Amino Acid Sequence; D000818:Animals; D001773:Blood Cells / Q000378:metabolism; D003304:Coproporphyrinogen Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004625:Embryo, Nonmammalian; D004920:Erythropoiesis; D050982:GATA1 Transcription Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006410:Hematopoiesis; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D051741:Kruppel-Like Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008845:Microinjections; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D050982:GATA1 Transcription Factor; D006454:Hemoglobins; D051741:Kruppel-Like Transcription Factors; D016376:Oligonucleotides, Antisense; D029961:Zebrafish Proteins; C494691:gata1a protein, zebrafish; C418487:klf4 protein, zebrafish; D003304:Coproporphyrinogen Oxidase