Oxygen sensing in Drosophila: Multiple isoforms of the prolyl hydroxylase fatiga have different capacity to regulate HIFαSima

• Autores: Acevedo, J.M.; Centanin, L.; Dekanty, A.; Wappner, P.
• Año de publicación: 2010
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: PLoS ONE 2010;5(8)
• Materia: hypoxia inducible factor; oxygenase; polyhistidine tag; procollagen proline 2 oxoglutarate 4 dioxygenase; prolyl 4 hydroxylase 1; prolyl 4 hydroxylase 2; prolyl 4 hydroxylase 3; unclassified drug; DNA binding protein; Drosophila protein; isoenzyme; messenger RNA; oxygen; procollagen proline 2 oxoglutarate 4 dioxygenase; Sima protein, Drosophila; alternative RNA splicing; animal cell; article; cell hypoxia; controlled study; Drosophila; embryo; gene expression regulation; gene locus; gene overexpression; imago; in vivo study; insect cell culture; intron; loss of function mutation; molecular dynamics; nonhuman; oxygen sensing; phenotypic variation; protein domain; protein localization; transcription initiation site; transgenics; animal; anoxia; chemistry; DNA responsive element; Drosophila melanogaster; enzymology; genetics; growth, development and aging; human; life cycle; metabolism; protein tertiary structure; upregulation; Mammalia; Alternative Splicing; Animals; Anoxia; DNA-Binding Proteins; Drosophila melanogaster; Drosophila Proteins; Gene Expression Regulation, Enzymologic; Genetic Loci; Humans; Isoenzymes; Life Cycle Stages; Oxygen; Procollagen-Proline Dioxygenase; Protein Structure, Tertiary; Response Elements; RNA, Messenger; Up-Regulation
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

Background: The Hypoxia Inducible Factor (HIF) mediates cellular adaptations to low oxygen. Prolyl-4-hydroxylases are oxygen sensors that hydroxylate the HIF alpha-subunit, promoting its proteasomal degradation in normoxia. Three HIFprolyl hydroxylases, encoded by independent genes, PHD1, PHD2, and PHD3, occur in mammals. PHD2, the longest PHD isoform includes a MYND domain, whose biochemical function is unclear. PHD2 and PHD3 genes are induced in hypoxia to shut down HIF dependent transcription upon reoxygenation, while expression of PHD1 is oxygen-independent. The physiologic significance of the diversity of the PHD oxygen sensors is intriguing. Methodology and Principal Findings: We have analyzed the Drosophila PHD locus, fatiga, which encodes 3 isoforms, FgaA, FgaB and FgaC that are originated through a combination of alternative initiation of transcription and alternative splicing. FgaA includes a MYND domain and is homologous to PHD2, while FgaB and FgaC are shorter isoforms most similar to PHD3. Through a combination of genetic experiments in vivo and molecular analyses in cell culture, we show that fgaB but not fgaA is induced in hypoxia, in a Sima-dependent manner, through a HIF-Responsive Element localized in the first intron of fgaA. The regulatory capacity of FgaB is stronger than that of FgaA, as complete reversion of fga loss-of-function phenotypes is observed upon transgenic expression of the former, and only partial rescue occurs after expression of the latter. Conclusions and Significance: Diversity of PHD isoforms is a conserved feature in evolution. As in mammals, there are hypoxia-inducible and non-inducible Drosophila PHDs, and a fly isoform including a MYND domain co-exists with isoforms lacking this domain. Our results suggest that the isoform devoid of a MYND domain has stronger regulatory capacity than that including this domain.
Fil:Acevedo, J.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Centanin, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Dekanty, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Wappner, P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.