Dataset Information

HIF- and non-HIF-regulated hypoxic responses require the estrogen-related receptor in Drosophila melanogaster.

ABSTRACT: Low-oxygen tolerance is supported by an adaptive response that includes a coordinate shift in metabolism and the activation of a transcriptional program that is driven by the hypoxia-inducible factor (HIF) pathway. The precise contribution of HIF-1a in the adaptive response, however, has not been determined. Here, we investigate how HIF influences hypoxic adaptation throughout Drosophila melanogaster development. We find that hypoxic-induced transcriptional changes are comprised of HIF-dependent and HIF-independent pathways that are distinct and separable. We show that normoxic set-points of carbohydrate metabolites are significantly altered in sima mutants and that these animals are unable to mobilize glycogen in hypoxia. Furthermore, we find that the estrogen-related receptor (dERR), which is a global regulator of aerobic glycolysis in larvae, is required for a competent hypoxic response. dERR binds to dHIFa and participates in the HIF-dependent transcriptional program in hypoxia. In addition, dERR acts in the absence of dHIFa in hypoxia and a significant portion of HIF-independent transcriptional responses can be attributed to dERR actions, including upregulation of glycolytic transcripts. These results indicate that competent hypoxic responses arise from complex interactions between HIF-dependent and -independent mechanisms, and that dERR plays a central role in both of these programs.

SUBMITTER: Li Y

PROVIDER: S-EPMC3561118 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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HIF- and non-HIF-regulated hypoxic responses require the estrogen-related receptor in Drosophila melanogaster.

Li Yan Y Padmanabha Divya D Gentile Luciana B LB Dumur Catherine I CI Beckstead Robert B RB Baker Keith D KD

PLoS genetics 20130131 1

Low-oxygen tolerance is supported by an adaptive response that includes a coordinate shift in metabolism and the activation of a transcriptional program that is driven by the hypoxia-inducible factor (HIF) pathway. The precise contribution of HIF-1a in the adaptive response, however, has not been determined. Here, we investigate how HIF influences hypoxic adaptation throughout Drosophila melanogaster development. We find that hypoxic-induced transcriptional changes are comprised of HIF-dependent ...[more]

PMID: 23382692

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Project description:Low-oxygen tolerance is supported by an adaptive response that includes a coordinate shift in metabolism and the activation of a transcriptional program that is driven by the hypoxia-inducible factor (HIF) pathway. The precise contribution of HIF-1 in the adaptive response, however, has not been determined. Here we investigate how HIF-1 influences hypoxic adaptation throughout Drosophila development. We find that hypoxic-induced transcriptional changes are comprised of HIF-dependent and HIF-independent pathways that are distinct and separable. We show that normoxic set-points of carbohydrate metabolites are significantly altered in dHIF mutants and that these animals are unable to mobilize glycogen in hypoxia. Furthermore, we find that the estrogen-related receptor (dERR), which is a global regulator of aerobic glycolysis in larvae, is required for a competent hypoxic response. dERR binds to dHIF and participates in the HIF-dependent transcriptional program in hypoxia. In addition, dERR acts in the absence of dHIF in hypoxia and a significant portion of HIF-independent transcriptional responses can be attributed to dERR actions, including upregulation of glycolytic transcripts. These results indicate that competent hypoxic responses arise from complex interactions between HIF-dependent and -independent mechanisms, and that dERR plays a central role in both of these programs. Fly eggs were collected onto egg caps with yeast paste . The caps were replaced after overnight incubation periods and kept at 25M-BM-:C, until mid-L2. At mid-L2, larvae were transferred to a fresh egg cap with blue yeast paste (0.3% bromophenol blue), and allowed to develop until achieving the partial clear gut L3 stage (-10 to -4 hrs prior to metamorphic onset). Appropriately staged animals were moved to fresh agar plates and allowed to age an additional 6 hours at 25M-BM-:C (normoxic treatment). Alternatively, animals were placed in an airtight Modular Incubator Chamber for 6 hours at 25M-BM-:C after a gas mixture containing 4% oxygen balanced with nitrogen was flashed into the chamber (hypoxic treatment). Mutant larvae were sorted for the absence of GFP expression using dissecting stereoscope with fluorescence at mid-L2. Microarray analyses were performed on at least three biological replicates of w1118, dHIF mutants, or dERR mutants at the partial clear gut third instar larval stage and were treated for 6 hours in normoxia or 4% O2. For each biological replicate, at least 10 larvae were collected and washed with 1M-CM-^WPBS. Larvae were placed in TRIzol (Invitrogen, Carlsbad, CA) and homogenized using VWR disposable pellet mixer. Total RNA was isolated using a TRIzol/RQ1 DNase (Promega, Madison, WI) hybrid extraction protocol. Template labelings were performed using the GeneChip 3' IVT Express Kit according to the manufacturerM-bM-^@M-^Ys specifications (Affymetrix, Santa Clara, CA). Hybridizations to Affymetrix GeneChip Drosophila Genome 2.0 arrays were performed using the manufacturers recommendations. Every chip was scanned at a high resolution by the Affymetrix GeneChipM-BM-. Scanner 3000 according to the GeneChip Expression Analysis Technical Manual procedures (Affymetrix, Santa Clara, CA).

Project description:BACKGROUND: Bursicon is a heterodimer neuropeptide responsible for regulating cuticle sclerotization and wing expansion in several insect species. Recent studies indicate that the action of bursicon is mediated by a specific G protein-coupled receptor DLGR2 and the cAMP/PKA signaling pathway. However, little is known regarding the genes that are regulated by bursicon. The identification of bursicon-regulated genes is the focus of this investigation. RESULTS: We used DNA microarray analysis to identify bursicon-regulated genes in neck-ligated flies (Drosophila melanogaster) that received recombinant bursicon (r-bursicon). Fifty four genes were found to be regulated by bursicon 1 h post r-bursicon injection, 52 being up-regulated and 2 down-regulated while 33 genes were influenced by r-bursicon 3 h post-injection (24 up-regulated and 9 down-regulated genes). Analysis of these genes by inference from the fly database http://flybase.bio.indiana.edu revealed that these genes encode proteins with diverse functions, including cell signaling, gene transcription, DNA/RNA binding, ion trafficking, proteolysis-peptidolysis, metabolism, cytoskeleton formation, immune response and cell-adhesion. Twenty eight genes randomly selected from the microarray-identified list were verified by real time PCR (qPCR) which supported the microarray data. Temporal response studies of 13 identified and verified genes by qPCR revealed that the temporal expression patterns of these genes are consistent with the microarray data. CONCLUSION: Using r-bursicon, we identified 87 genes that are regulated by bursicon, 30 of which have no previously known function. Most importantly, all genes randomly selected from the microarray-identified list were verified by real time PCR. Temporal analysis of 13 verified genes revealed that the expression of these genes was indeed induced by bursicon and correlated well with the cuticle sclerotization process. The composite data suggest that these genes play important roles in regulating the cuticle sclerotization and wing expansion processes. The data obtained here will form the basis for future studies aimed at elucidating the exact mechanisms upstream from the secretion of bursicon and its binding to target cells.

Dataset Information

HIF- and non-HIF-regulated hypoxic responses require the estrogen-related receptor in Drosophila melanogaster.

Publications

HIF- and non-HIF-regulated hypoxic responses require the estrogen-related receptor in Drosophila melanogaster.

Similar Datasets

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