251
|
Tanaka Y. Recent topics on the regulatory mechanism of ecdysteroidogenesis by the prothoracic glands in insects. Front Endocrinol (Lausanne) 2011; 2:107. [PMID: 22645515 PMCID: PMC3355830 DOI: 10.3389/fendo.2011.00107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 12/06/2011] [Indexed: 11/30/2022] Open
Abstract
Molting and metamorphosis are strictly regulated by steroid hormones known as ecdysteroids. It is now widely recognized that ecdysteroid biosynthesis (ecdysteroidogenesis) in the prothoracic gland (PG) is regulated by the tropic factor prothoracicotropic hormone (PTTH). However, the importance of PTTH in the induction of molting and metamorphosis remains unclear, and other mechanisms are thought to be involved in the regulation of ecdysteroidogenesis by the PG. Recently, new regulatory mechanisms, prothoracicostatic factors, and neural regulation have been explored using the silkworm, Bombyx mori, and two circulating prothoracicostatic factors, prothoracicostatic peptide (PTSP) and Bommo-myosuppressin (BMS), have been identified. Whereas PTTH and BMS are secreted from the brain, PTSP is secreted from the peripheral neurosecretory system - the epiproctodeal gland - during the molting stage. The molecular basis of neural regulation of ecdysteroidogenesis has been revealed for the first time in B. mori. The innervating neurons supply both Bommo-FMRF related peptide (BRFa) and orcokinin to maintain low levels of ecdysteroids during the feeding stage. These complex regulatory mechanisms - involving tropic and static factors, peripheral neurosecretory cells as well as the central neuroendocrine system, and neural regulation in addition to circulating factors collaborate to regulate ecdysteroidogenesis. Thus, together they create the finely tuned fluctuations in ecdysteroid titers needed in the hemolymph during insect development.
Collapse
Affiliation(s)
- Yoshiaki Tanaka
- Insect Growth Regulation Research Unit, Division of Insect Science, National Institute of Agrobiological SciencesTsukuba, Japan
| |
Collapse
|
252
|
Lin JI, Mitchell NC, Kalcina M, Tchoubrieva E, Stewart MJ, Marygold SJ, Walker CD, Thomas G, Leevers SJ, Pearson RB, Quinn LM, Hannan RD. Drosophila ribosomal protein mutants control tissue growth non-autonomously via effects on the prothoracic gland and ecdysone. PLoS Genet 2011; 7:e1002408. [PMID: 22194697 PMCID: PMC3240600 DOI: 10.1371/journal.pgen.1002408] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 10/20/2011] [Indexed: 11/30/2022] Open
Abstract
The ribosome is critical for all aspects of cell growth due to its essential role in protein synthesis. Paradoxically, many Ribosomal proteins (Rps) act as tumour suppressors in Drosophila and vertebrates. To examine how reductions in Rps could lead to tissue overgrowth, we took advantage of the observation that an RpS6 mutant dominantly suppresses the small rough eye phenotype in a cyclin E hypomorphic mutant (cycEJP). We demonstrated that the suppression of cycEJP by the RpS6 mutant is not a consequence of restoring CycE protein levels or activity in the eye imaginal tissue. Rather, the use of UAS-RpS6 RNAi transgenics revealed that the suppression of cycEJP is exerted via a mechanism extrinsic to the eye, whereby reduced Rp levels in the prothoracic gland decreases the activity of ecdysone, the steroid hormone, delaying developmental timing and hence allowing time for tissue and organ overgrowth. These data provide for the first time a rationale to explain the counter-intuitive organ overgrowth phenotypes observed for certain members of the Minute class of Drosophila Rp mutants. They also demonstrate how Rp mutants can affect growth and development cell non-autonomously. Ribosomes are required for protein synthesis, which is essential for cell growth and division, thus mutations that reduce Rp expression would be expected to limit cell growth. Paradoxically, heterozygous deletion or mutation of certain Rps can actually promote growth and proliferation and in some cases bestow predisposition to cancer. The underlying mechanism(s) behind these unexpected overgrowth phenotypes despite impairment of ribosome biogenesis has remained obscure. We have addressed this question using the power of Drosophila genetics, taking advantage of our observation that four different Rp mutants, or Minutes, are able to suppress a small rough eye phenotype associated with a mutation of the essential controller of cell proliferation cyclin E (cycEJP). Our findings demonstrate that suppression of cycEJP by the RpS6 mutant is exerted via a tissue non-autonomous mechanism whereby reduced Rp in the prothoracic gland decreases activity of the steroid hormone ecdysone, delaying development and hence allowing time for compensatory growth. These data provide for the first time a rationale to explain the counter-intuitive organ overgrowth phenotypes observed for certain Drosophila Minutes. Our findings also have implications for the effect of Rp mutants on endocrine related control of tissue growth in higher organisms.
Collapse
Affiliation(s)
- Jane I. Lin
- Peter MacCallum Cancer Centre, East Melbourne, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Australia
| | - Naomi C. Mitchell
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Australia
| | - Marina Kalcina
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Australia
| | | | - Mary J. Stewart
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, United States of America
| | - Steven J. Marygold
- Growth Regulation Laboratory, Cancer Research UK London Research Institute, London, United Kingdom
| | - Cherryl D. Walker
- Growth Regulation Laboratory, Cancer Research UK London Research Institute, London, United Kingdom
| | - George Thomas
- University of Cincinnati Medical Center, Cincinnati, Ohio, United States of America
| | - Sally J. Leevers
- Growth Regulation Laboratory, Cancer Research UK London Research Institute, London, United Kingdom
| | - Richard B. Pearson
- Peter MacCallum Cancer Centre, East Melbourne, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Cell Biology, Monash University, Clayton, Australia
| | - Leonie M. Quinn
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Australia
- * E-mail: (LMQ); (RDH)
| | - Ross D. Hannan
- Peter MacCallum Cancer Centre, East Melbourne, Australia
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Cell Biology, Monash University, Clayton, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
- * E-mail: (LMQ); (RDH)
| |
Collapse
|
253
|
Monsalve GC, Van Buskirk C, Frand AR. LIN-42/PERIOD controls cyclical and developmental progression of C. elegans molts. Curr Biol 2011; 21:2033-45. [PMID: 22137474 DOI: 10.1016/j.cub.2011.10.054] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 10/07/2011] [Accepted: 10/31/2011] [Indexed: 01/06/2023]
Abstract
BACKGROUND Biological timing mechanisms that integrate cyclical and successive processes are not well understood. C. elegans molting cycles involve rhythmic cellular and animal behaviors linked to the periodic reconstruction of cuticles. Molts are coordinated with successive transitions in the temporal fates of epidermal blast cells, which are programmed by genes in the heterochronic regulatory network. It was known that juveniles molt at regular 8-10 hr intervals, but the anticipated pacemaker had not been characterized. RESULTS We find that inactivation of the heterochronic gene lin-42a, which is related to the core circadian clock gene PERIOD (PER), results in arrhythmic molts and continuously abnormal epidermal stem cell dynamics. The oscillatory expression of lin-42a in the epidermis peaks during the molts. Further, forced expression of lin-42a leads to anachronistic larval molts and lethargy in adults. CONCLUSIONS Our results suggest that rising and falling levels of LIN-42A allow the start and completion, respectively, of larval molts. We propose that LIN-42A and affiliated factors regulate molting cycles in much the same way that PER-based oscillators drive rhythmic behaviors and metabolic processes in mature mammals. Further, the combination of reiterative and stage-specific functions of LIN-42 may coordinate periodic molts with successive development of the epidermis.
Collapse
Affiliation(s)
- Gabriela C Monsalve
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | | |
Collapse
|
254
|
Gancz D, Lengil T, Gilboa L. Coordinated regulation of niche and stem cell precursors by hormonal signaling. PLoS Biol 2011; 9:e1001202. [PMID: 22131903 PMCID: PMC3222635 DOI: 10.1371/journal.pbio.1001202] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 10/17/2011] [Indexed: 11/19/2022] Open
Abstract
In the developing Drosophila ovary, the ecdysone signaling pathway controls the differentiation of both niche and germ line stem cell precursors. Stem cells and their niches constitute units that act cooperatively to achieve adult body homeostasis. How such units form and whether stem cell and niche precursors might be coordinated already during organogenesis are unknown. In fruit flies, primordial germ cells (PGCs), the precursors of germ line stem cells (GSCs), and somatic niche precursors develop within the larval ovary. Together they form the 16–20 GSC units of the adult ovary. We show that ecdysone receptors are required to coordinate the development of niche and GSC precursors. At early third instar, ecdysone receptors repress precocious differentiation of both niches and PGCs. Early repression is required for correct morphogenesis of the ovary and for protecting future GSCs from differentiation. At mid-third instar, ecdysone signaling is required for niche formation. Finally, and concurrent with the initiation of wandering behavior, ecdysone signaling initiates PGC differentiation by allowing the expression of the differentiation gene bag of marbles in PGCs that are not protected by the newly formed niches. All the ovarian functions of ecdysone receptors are mediated through early repression, and late activation, of the ecdysone target gene broad. These results show that, similar to mammals, a brain-gland-gonad axis controls the initiation of oogenesis in insects. They further exemplify how a physiological cue coordinates the formation of a stem cell unit within an organ: it is required for niche establishment and to ensure that precursor cells to adult stem cells remain undifferentiated until the niches can accommodate them. Similar principles might govern the formation of additional stem cell units during organogenesis. Tissue-specific stem cells reside in specialized microenvironments (niches). How the generation of niche cells and resident stem cells is coordinated, and how their correct numerical ratios are regulated, remains poorly understood. Here, we examine the potential mechanisms of this process by analyzing the formation of the fly ovary. Specifically, we uncover a role for ecdysone, which is a steroid hormone renowned for its role in insect molting but that also controls many aspects of larval development in flies and mammals. We find that ecdysone signaling in fly larvae coordinates the development of niche cells relative to their resident germ line stem cells (GSCs). Ecdysone receptors initially serve as repressors of differentiation, allowing precursor cells of both niches and GSCs time to proliferate and attain correct cell numbers. Later, ecdysone receptors allow differentiation of niches while simultaneously maintaining GSC precursors in an undifferentiated state, until the newly formed niches can accommodate them. Finally, ecdysone induces the differentiation of GSC precursors that are not incorporated in niches. Our work exemplifies one possible solution to coordinating stem cell and niche development: using a common signal to affect both cell types. A further understanding of these and other mechanisms will offer novel insights into regeneration and could help guide cell-based therapies for various diseases.
Collapse
Affiliation(s)
- Dana Gancz
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Lengil
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Lilach Gilboa
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
- * E-mail:
| |
Collapse
|
255
|
Ou Q, Magico A, King-Jones K. Nuclear receptor DHR4 controls the timing of steroid hormone pulses during Drosophila development. PLoS Biol 2011; 9:e1001160. [PMID: 21980261 PMCID: PMC3181225 DOI: 10.1371/journal.pbio.1001160] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 08/15/2011] [Indexed: 12/15/2022] Open
Abstract
Pulses of the steroid hormone ecdysone are turned off periodically through nucleo-cytoplasmic oscillations of a nuclear receptor that counteracts the neuropeptide signaling pathway responsible for activating hormone pulses in Drosophila melanogaster. In insects, precisely timed periodic pulses of the molting hormone ecdysone control major developmental transitions such as molts and metamorphosis. The synthesis and release of ecdysone, a steroid hormone, is itself controlled by PTTH (prothoracicotopic hormone). PTTH transcript levels oscillate with an 8 h rhythm, but its significance regarding the timing of ecdysone pulses is unclear. PTTH acts on its target tissue, the prothoracic gland (PG), by activating the Ras/Raf/ERK pathway through its receptor Torso, however direct targets of this pathway have yet to be identified. Here, we demonstrate that Drosophila Hormone Receptor 4 (DHR4), a nuclear receptor, is a key target of the PTTH pathway and establishes temporal boundaries by terminating ecdysone pulses. Specifically, we show that DHR4 oscillates between the nucleus and cytoplasm of PG cells, and that the protein is absent from PG nuclei at developmental times when low titer ecdysone pulses occur. This oscillatory behavior is blocked when PTTH or torso function is abolished, resulting in nuclear accumulation of DHR4, while hyperactivating the PTTH pathway results in cytoplasmic retention of the protein. Increasing DHR4 levels in the PG can delay or arrest development. In contrast, reducing DHR4 function in the PG triggers accelerated development, which is caused by precocious ecdysone signaling due to a failure to repress ecdysone pulses. Finally, we show that DHR4 negatively regulates the expression of a hitherto uncharacterized cytochrome P450 gene, Cyp6t3. Disruption of Cyp6t3 function causes low ecdysteroid titers and results in heterochronic phenotypes and molting defects, indicating a novel role in the ecdysone biosynthesis pathway. We propose a model whereby nuclear DHR4 controls the duration of ecdysone pulses by negatively regulating ecdysone biosynthesis through repression of Cyp6t3, and that this repressive function is temporarily overturned via the PTTH pathway by removing DHR4 from the nuclear compartment. Steroid hormones play fundamental roles in development and disease. They are often released as pulses, thereby orchestrating multiple physiological and developmental changes throughout the body. Hormone pulses must be regulated in a way so that they have a defined beginning, peak, and end. In Drosophila, pulses of the steroid hormone ecdysone govern all major developmental transitions, such as the molts or the transformation of a larva to a pupa. While we have a relatively good understanding of how an ecdysone pulse is initiated, little is known about how hormone production is turned off. In this study, we identify a critical regulator of this process, the nuclear receptor DHR4. When we interfere with the function of DHR4 specifically in the ecdysone-producing gland, we find that larvae develop much faster than normal, and that this is caused by the inability to turn off ecdysone production. We show that DHR4 oscillates between cytoplasm and nucleus of ecdysone-producing cells under the control of a neuropeptide that regulates ecdysone production. When the neuropeptide pathway is inactive, DHR4 enters the nucleus and represses another gene, Cyp6t3, for which we show a novel role in the production of ecdysone.
Collapse
Affiliation(s)
- Qiuxiang Ou
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Adam Magico
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Kirst King-Jones
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
| |
Collapse
|
256
|
Control of body size by oxygen supply reveals size-dependent and size-independent mechanisms of molting and metamorphosis. Proc Natl Acad Sci U S A 2011; 108:14664-9. [PMID: 21873228 DOI: 10.1073/pnas.1106556108] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Body size profoundly affects many aspects of animal biology, including metamorphosis, allometry, size-dependent alternative pathways of gene expression, and the social and ecological roles of individuals. However, regulation of body size is one of the fundamental unsolved problems in developmental biology. The control of body size requires a mechanism that assesses size and stops growth within a characteristic range of sizes. Under normal growth conditions in Manduca sexta, the endocrine cascade that causes the brain to initiate metamorphosis starts when the larva reaches a critical weight. Metamorphosis is initiated by a size-sensing mechanism, but the nature of this mechanism has remained elusive. Here we show that this size-sensing mechanism depends on the limited ability of a fixed tracheal system to sustain the oxygen supply to a growing individual. As body mass increases, the demand for oxygen also increases, but the fixed tracheal system does not allow a corresponding increase in oxygen supply. We show that interinstar molting has the same size-related oxygen-dependent mechanism of regulation as metamorphosis. We show that low oxygen tension induces molting at smaller body size, consistent with the hypothesis that under normal growth conditions, body size is regulated by a mechanism that senses oxygen limitation. We also found that under poor growth conditions, larvae may never attain the critical weight but eventually molt regardless. We show that under these conditions, larvae do not use the critical weight mechanism, but instead use a size-independent mechanism that is independent of the brain.
Collapse
|
257
|
Stojković B, Jovanović DŠ, Perovanović J, Tucić N. Sexual Activity and Reproductive Isolation Between Age-specific Selected Populations of Seed Beetle. Ethology 2011. [DOI: 10.1111/j.1439-0310.2011.01936.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
258
|
Parker NF, Shingleton AW. The coordination of growth among Drosophila organs in response to localized growth-perturbation. Dev Biol 2011; 357:318-25. [PMID: 21777576 DOI: 10.1016/j.ydbio.2011.07.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 06/30/2011] [Accepted: 07/02/2011] [Indexed: 11/25/2022]
Abstract
The developmental mechanisms by which growth is coordinated among developing organs are largely unknown and yet are essential to generate a correctly proportioned adult. In particular, such coordinating mechanisms must be able to accommodate perturbations in the growth of individual organs caused by environmental or developmental stress. By autonomously slowing the growth of the developing wing discs within Drosophila larvae, we show that growing organs are able to signal localized growth perturbation to the other organs in the body and slow their growth also. Growth rate is so tightly coordinated among organs that they all show approximately the same reduction in growth rate as the developing wings, thereby maintaining their correct size relationship relative to one another throughout development. Further, we show that the systemic growth effects of localized growth-perturbation are mediated by ecdysone. Application of ecdysone to larvae with growth-perturbed wing discs rescues the growth rate of other organs in the body, indicating that ecdysone is limiting for their growth, and disrupts the coordination of their growth with growth of the wing discs. Collectively our data demonstrate the existence of a novel growth-coordinating mechanism in Drosophila that synchronizes growth among organs in response to localized growth perturbation.
Collapse
Affiliation(s)
- Nathan F Parker
- Department of Zoology, Michigan State University, East Lansing, Michigan 48824, USA
| | | |
Collapse
|
259
|
Cáceres L, Necakov AS, Schwartz C, Kimber S, Roberts IJH, Krause HM. Nitric oxide coordinates metabolism, growth, and development via the nuclear receptor E75. Genes Dev 2011; 25:1476-85. [PMID: 21715559 DOI: 10.1101/gad.2064111] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nitric oxide gas acts as a short-range signaling molecule in a vast array of important physiological processes, many of which include major changes in gene expression. How these genomic responses are induced, however, is poorly understood. Here, using genetic and chemical manipulations, we show that nitric oxide is produced in the Drosophila prothoracic gland, where it acts via the nuclear receptor ecdysone-induced protein 75 (E75), reversing its ability to interfere with its heterodimer partner, Drosophila hormone receptor 3 (DHR3). Manipulation of these interactions leads to gross alterations in feeding behavior, fat deposition, and developmental timing. These neuroendocrine interactions and consequences appear to be conserved in vertebrates.
Collapse
Affiliation(s)
- Lucía Cáceres
- Banting and Best Department of Medical Research, Department of Molecular Biology, University of Toronto, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
260
|
Ohtsuka K, Atsumi T, Fukushima Y, Shiomi K. Identification of a cis-regulatory element that directs prothoracicotropic hormone gene expression in the silkworm Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:356-361. [PMID: 21324358 DOI: 10.1016/j.ibmb.2011.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 01/19/2011] [Accepted: 02/07/2011] [Indexed: 05/30/2023]
Abstract
In the silkworm Bombyx mori and other insects, prothoracicotropic hormone (PTTH) plays a central role in controlling molting and metamorphosis by stimulating the prothoracic glands to synthesize and release the molting hormone ecdysone. Using an AcNPV (Autographa californica nucleopolyhedrovirus)-mediated transient gene transfer system, we identified a cis-regulatory element that participates in the decision to switch expression of PTTH on or off in PTTH-producing neurosecretory cells (PTPCs). The nucleotide sequence of this cis-regulatory element is similar to a cis-regulatory element that participates in direction of expression of diapause hormone-pheromone biosynthesis activating neuropeptide gene (DH-PBAN) (Shiomi et al., 2007). Furthermore, we found that B. mori Pitx (BmPitx), a bicoid-like homeobox transcription factor, binds the element and activates PTTH expression. Therefore, we propose that the cell-specific expression of two neuropeptide hormone genes, PTTH and DH-PBAN, is activated by the Pitx transcription factor, which may act as a pan-activator in the insect neuroendocrine system and in vertebrate pituitary cells.
Collapse
Affiliation(s)
- Kazunori Ohtsuka
- Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan
| | | | | | | |
Collapse
|
261
|
Gibbens YY, Warren JT, Gilbert LI, O'Connor MB. Neuroendocrine regulation of Drosophila metamorphosis requires TGFbeta/Activin signaling. Development 2011; 138:2693-703. [PMID: 21613324 DOI: 10.1242/dev.063412] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In insects, initiation of metamorphosis requires a surge in the production of the steroid hormone 20-hydroxyecdysone from the prothoracic gland, the primary endocrine organ of juvenile larvae. Here, we show that blocking TGFβ/Activin signaling, specifically in the Drosophila prothoracic gland, results in developmental arrest prior to metamorphosis. The terminal, giant third instar larval phenotype results from a failure to induce the large rise in ecdysteroid titer that triggers metamorphosis. We further demonstrate that activin signaling regulates competence of the prothoracic gland to receive PTTH and insulin signals, and that these two pathways act at the mRNA and post-transcriptional levels, respectively, to control ecdysone biosynthetic enzyme expression. This dual regulatory circuitry may provide a cross-check mechanism to ensure that both developmental and nutritional inputs are synchronized before initiating the final genetic program leading to reproductive adult development. As steroid hormone production in C. elegans and mammals is also influenced by TGFβ/Activin signaling, this family of secreted factors may play a general role in regulating developmental transitions across phyla.
Collapse
Affiliation(s)
- Ying Y Gibbens
- Department of Genetics Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | | | |
Collapse
|
262
|
Zhang Q, Denlinger DL. Molecular structure of the prothoracicotropic hormone gene in the northern house mosquito, Culex pipiens, and its expression analysis in association with diapause and blood feeding. INSECT MOLECULAR BIOLOGY 2011; 20:201-13. [PMID: 21118326 PMCID: PMC3059851 DOI: 10.1111/j.1365-2583.2010.01058.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We cloned the gene that encodes prothoracicotropic hormone (PTTH) in the northern house mosquito, Culex pipiens, and investigated its expression profile in short-day (diapause-destined) and long-day (nondiapause-destined) individuals from the fourth-instar larval stage to 2 months of adulthood, as well as after a blood meal. The deduced C. pipiens PTTH (Cupip-PTTH) amino acid sequence contains seven cysteines with a specific spacing pattern. Sequence alignment suggests that Cupip-PTTH is 23% identical to Drosophila melanogaster PTTH, but is ≥59% identical to the PTTHs of other mosquitoes. Cupip-PTTH has structural characteristics similar to those of Bombyx mori PTTH and some vertebrate nerve growth factors with cysteine-knot motifs. PTTH transcripts exhibit a daily cycling profile during the final (fourth) larval instar, with peak abundance occurring late in the scotophase. The fourth-larval instar stage is one day longer in short-day larvae than in long-day larvae, resulting in larger larvae and adults. This additional day of larval development is associated with one extra PTTH cycle. No cycling was observed in pupae, but PTTH transcripts were slightly higher in short-day pupae than in long-day pupae throughout much of the pupal stage. PTTH expression persisted at a nearly constant level in diapausing adult females for the first month but then dropped by ∼50%, while expression decreased at the beginning of adulthood in nondiapausing females and then remained at a low level as long as the females were denied a blood meal. However, when nondiapausing females were offered a blood meal, PTTH transcripts rose approximately 7 fold in 2 h and remained elevated for 24 h. A few diapausing females (∼10%) will take a blood meal when placed in close proximity to a host, but much of the blood is ejected and such meals do not result in mature eggs. Yet, elevated PTTH mRNA expression was also observed in diapausing females that were force fed. Our results thus point to several distinctions in PTTH expression between short-day and long-day mosquitoes, but both types of females responded to a blood meal by elevating levels of PTTH mRNA.
Collapse
Affiliation(s)
- Qirui Zhang
- Department of Entomology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA
| | - David L. Denlinger
- Department of Entomology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA
- Corresponding author. Tel.: +1 614 2926425; Fax: +1 614 2922180. (D.L. Denlinger)
| |
Collapse
|
263
|
Yamanaka N, Roller L, Zitňan D, Satake H, Mizoguchi A, Kataoka H, Tanaka Y. Bombyx orcokinins are brain-gut peptides involved in the neuronal regulation of ecdysteroidogenesis. J Comp Neurol 2011; 519:238-46. [PMID: 21165973 DOI: 10.1002/cne.22517] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Biosynthesis of ecdysteroids, the insect steroid hormones controlling gene expression during molting and metamorphosis, takes place primarily in the prothoracic gland (PG). The activity of the PG is regulated by various neuropeptides. In the silkworm Bombyx mori, these neuropeptides utilize both hormonal and neuronal pathways to regulate the activity of the PG, making the insect an excellent model system to investigate the complex signaling network controlling ecdysteroid biosynthesis. Here we report another group of neuropeptides, orcokinins, as neuronal prothoracicotropic factors. Using direct mass spectrometric profiling of the axons associated with the PG, we detected several peptide peaks which correspond to orcokinin gene products in addition to the previously described Bommo-FMRFamides (BRFas). In situ hybridization and immunohistochemistry revealed that orcokinins are produced in the prominent neurosecretory cells in the ventral ganglia, as well as in numerous small neurons throughout the central nervous system and in midgut endocrine cells. One of the two pairs of BRFa-expressing neurosecretory cells in the prothoracic ganglion coexpresses orcokinin, and these neurons project axons through the transverse nerve and terminate on the surface of the PG. Using an in vitro PG bioassay, we show that orcokinins have a clear prothoracicotropic activity and are able to cancel the static effect of BRFas on ecdysteroid biosynthesis, whereas the suppressive effect of BRFas on cAMP production remained unchanged in the presence of orcokinins. The discovery of a second regulator of PG activity in these neurons further illustrates the potential importance of the PG innervation in the regulation of insect development.
Collapse
Affiliation(s)
- Naoki Yamanaka
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Chiba, Japan
| | | | | | | | | | | | | |
Collapse
|
264
|
König A, Yatsenko AS, Weiss M, Shcherbata HR. Ecdysteroids affect Drosophila ovarian stem cell niche formation and early germline differentiation. EMBO J 2011; 30:1549-62. [PMID: 21423150 PMCID: PMC3102283 DOI: 10.1038/emboj.2011.73] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 02/22/2011] [Indexed: 01/13/2023] Open
Abstract
Previously, it has been shown that in Drosophila steroid hormones are required for progression of oogenesis during late stages of egg maturation. Here, we show that ecdysteroids regulate progression through the early steps of germ cell lineage. Upon ecdysone signalling deficit germline stem cell progeny delay to switch on a differentiation programme. This differentiation impediment is associated with reduced TGF-β signalling in the germline and increased levels of cell adhesion complexes and cytoskeletal proteins in somatic escort cells. A co-activator of the ecdysone receptor, Taiman is the spatially restricted regulator of the ecdysone signalling pathway in soma. Additionally, when ecdysone signalling is perturbed during the process of somatic stem cell niche establishment enlarged functional niches able to host additional stem cells are formed.
Collapse
Affiliation(s)
- Annekatrin König
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | | | | | | |
Collapse
|
265
|
Gu SH, Young SC, Lin JL, Lin PL. Involvement of PI3K/Akt signaling in PTTH-stimulated ecdysteroidogenesis by prothoracic glands of the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:197-202. [PMID: 21199670 DOI: 10.1016/j.ibmb.2010.12.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 12/11/2010] [Accepted: 12/19/2010] [Indexed: 05/30/2023]
Abstract
The prothoracicotropic hormone (PTTH) stimulates ecdysteroidogenesis by prothoracic gland in larval insects. Previous studies showed that Ca(2+), cAMP, extracellular signal-regulated kinase (ERK), and tyrosine kinase are involved in PTTH-stimulated ecdysteroidogenesis by the prothoracic glands of both Bombyx mori and Manduca sexta. In the present study, the involvement of phosphoinositide 3-kinase (PI3K)/Akt signaling in PTTH-stimulated ecdysteroidogenesis by B. mori prothoracic glands was further investigated. The results showed that PTTH-stimulated ecdysteroidogenesis was partially blocked by LY294002 and wortmannin, indicating that PI3K is involved in PTTH-stimulated ecdysteroidogenesis. Akt phosphorylation in the prothoracic glands appeared to be moderately stimulated by PTTH in vitro. PTTH-stimulated Akt phosphorylation was inhibited by LY294002. An in vivo PTTH injection into day 6 last instar larvae also increased Akt phosphorylation of the prothoracic glands. In addition, PTTH-stimulated ERK phosphorylation of the prothoracic glands was not inhibited by either LY294002 or wortmannin, indicating that PI3K is not involved in PTTH-stimulated ERK signaling. A23187 and thapsigargin, which stimulated B. mori prothoracic gland ERK phosphorylation and ecdysteroidogenesis, could not activate Akt phosphorylation. PTTH-stimulated ecdysteroidogenesis was not further activated by insulin, indicating the absence of an additive action of insulin and PTTH on the prothoracic glands. The present study, together with the previous demonstration that insulin stimulates B. mori ecdysteroidogenesis through PI3K/Akt signaling, suggests that crosstalk exists in B. mori prothoracic glands between insulin and PTTH signaling, which may play a critical role in precisely regulated ecdysteroidogenesis during development.
Collapse
Affiliation(s)
- Shi-Hong Gu
- Department of Zoology, National Museum of Natural Science, 1 Kuan-Chien Road, Taichung 404, Taiwan, ROC.
| | | | | | | |
Collapse
|
266
|
Schiesari L, Kyriacou CP, Costa R. The hormonal and circadian basis for insect photoperiodic timing. FEBS Lett 2011; 585:1450-60. [PMID: 21354417 DOI: 10.1016/j.febslet.2011.02.026] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 02/07/2011] [Accepted: 02/21/2011] [Indexed: 01/17/2023]
Abstract
Daylength perception in temperate zones is a critical feature of insect life histories, and leads to developmental changes for resisting unfavourable seasons. The role of the neuroendocrine axis in the photoperiodic response of insects is discussed in relation to the key organs and molecules that are involved. We also discuss the controversial issue of the possible involvement of the circadian clock in photoperiodicity. Drosophila melanogaster has a shallow photoperiodic response that leads to reproductive arrest in adults, yet the unrivalled molecular genetic toolkit available for this model insect should allow the systematic molecular and neurobiological dissection of this complex phenotype.
Collapse
|
267
|
Rewitz KF, Yamanaka N, O'Connor MB. Steroid hormone inactivation is required during the juvenile-adult transition in Drosophila. Dev Cell 2011; 19:895-902. [PMID: 21145504 DOI: 10.1016/j.devcel.2010.10.021] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 10/17/2010] [Accepted: 10/18/2010] [Indexed: 11/17/2022]
Abstract
Steroid hormones are systemic signaling molecules that regulate juvenile-adult transitions in both insects and mammals. In insects, pulses of the steroid hormone 20-hydroxyecdysone (20E) are generated by increased biosynthesis followed by inactivation/clearance. Although mechanisms that control 20E synthesis have received considerable recent attention, the physiological significance of 20E inactivation remains largely unknown. We show that the cytochrome P450 Cyp18a1 lowers 20E titer during the Drosophila prepupal to pupal transition. Furthermore, this reduction of 20E levels is a prerequisite to induce βFTZ-F1, a key factor in the genetic hierarchy that controls early metamorphosis. Resupplying βFTZ-F1 rescues Cyp18a1-deficient prepupae. Because Cyp18a1 is 20E-inducible, it appears that the increased production of steroid is responsible for its eventual decline, thereby generating the regulatory pulse required for proper temporal progression of metamorphosis. The coupling of hormone clearance to βFTZ-F1 expression suggests a general mechanism by which transient signaling drives unidirectional progression through a multistep process.
Collapse
Affiliation(s)
- Kim F Rewitz
- Department of Science, Roskilde University, Denmark
| | | | | |
Collapse
|
268
|
Ilijin L, Vlahović M, Mrdaković M, Mirčić D, Prolić Z, Lazarević J, Perić-Mataruga V. The effects of acute exposure to magnetic fields on morphometric characteristics of bombyxin-producing neurosecretory neurons in gypsy moth caterpillars. Int J Radiat Biol 2011; 87:461-71. [PMID: 21219112 DOI: 10.3109/09553002.2011.542544] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To examine the effects of acute exposure to strong static magnetic fields and extremely low frequency magnetic fields, on neurosecretory neurons which synthesise insulin-like neurohormone. MATERIALS AND METHODS Immunocytochemical detection of bombyxin-like material in the protocerebral neurosecretory neurons of Lymantria dispar caterpillars was performed using a monoclonal antibody directed against a synthetic dekapeptide corresponding to the N-terminus of the bombyxin A-chain. Caterpillars were exposed to strong static magnetic fileds (235 mT) and extremely low frequency magnetic fields (2 mT) for three days after moulting into the 4th instar. RESULTS We report the presence of immunoreactive molecules in A2 type of medial neurosecretory neurons (nsn) in caterpillars' brain of L. dispar. The three-day exposure of caterpillars to stresogenic external magnetic fields changed the size of A2 type nsn, their nuclei and the intensity of protein band in the region of bombyxin molecular mass (4-6 kD) after exposure to extremely low frequency magnetic fields in comparison to control group and group treated by strong static magnetic fields. CONCLUSION These are the first data on the influence of external magnetic fields on the polyphagous phytophagous forest pest L. dispar L. (Lepidoptera: Lymantridae) indicating an intensive synthesis of insulin-like neurosecretory material.
Collapse
Affiliation(s)
- Larisa Ilijin
- Department of Insect Physiology and Biochemistry, University of Belgrade, Institute for Biological Research Siniša Stanković, Belgrade, Serbia.
| | | | | | | | | | | | | |
Collapse
|
269
|
CYP18A1, a key enzyme of Drosophila steroid hormone inactivation, is essential for metamorphosis. Dev Biol 2011; 349:35-45. [DOI: 10.1016/j.ydbio.2010.09.023] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 09/28/2010] [Accepted: 09/28/2010] [Indexed: 12/16/2022]
|
270
|
Rewitz KF, O’Connor MB. Timing is Everything: PTTH Mediated DHR4 Nucleocytoplasmic Trafficking Sets the Tempo of Drosophila Steroid Production. Front Endocrinol (Lausanne) 2011; 2:108. [PMID: 22649397 PMCID: PMC3355928 DOI: 10.3389/fendo.2011.00108] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 12/06/2011] [Indexed: 11/13/2022] Open
Abstract
During development, multicellular organisms must become sexually mature in order to reproduce. The developmental timing of this transition is controlled by pulses of steroid hormones, but how these pulses are generated have remained unclear? A recent paper shows that in Drosophila larvae, nucleocytoplasmic trafficking of DHR4, a nuclear receptor, in response to prothoracicotropic hormone signaling, is critical for producing the correct temporal pulses of steroid hormones that coordinate the juvenile-adult transition.
Collapse
Affiliation(s)
- Kim F. Rewitz
- Department of Science, Systems and Models, Roskilde UniversityRoskilde, Denmark
| | - Michael B. O’Connor
- Department of Genetics, Cell Biology and Development, University of MinnesotaMinneapolis, MN, USA
- *Correspondence: Michael B. O’Connor, Department of Genetics Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, Minneapolis, MN 55455, USA. e-mail:
| |
Collapse
|
271
|
Gáliková M, Klepsatel P, Senti G, Flatt T. Steroid hormone regulation of C. elegans and Drosophila aging and life history. Exp Gerontol 2010; 46:141-7. [PMID: 20854888 DOI: 10.1016/j.exger.2010.08.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 08/19/2010] [Accepted: 08/27/2010] [Indexed: 10/19/2022]
Abstract
In the last two decades it has become clear that hormones and gene mutations in endocrine signaling pathways can exert major effects on lifespan and related life history traits in worms, flies, mice, and other organisms. While most of this research has focused on insulin/insulin-like growth factor-1 signaling, a peptide hormone pathway, recent work has shown that also lipophilic hormones play an important role in modulating lifespan and other life history traits. Here we review how steroid hormones, a particular group of lipophilic hormones, affect life history traits in the nematode worm (Caenorhabditis elegans) and the fruit fly (Drosophila melanogaster), with a particular focus on longevity. Interestingly, a comparison suggests that parallel endocrine principles might be at work in worms and flies in these species and that steroid hormones interact with the gonad to affect lifespan.
Collapse
Affiliation(s)
- Martina Gáliková
- Institute of Population Genetics, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Vienna, Austria
| | | | | | | |
Collapse
|
272
|
Ghosh A, McBrayer Z, O'Connor MB. The Drosophila gap gene giant regulates ecdysone production through specification of the PTTH-producing neurons. Dev Biol 2010; 347:271-8. [PMID: 20816678 DOI: 10.1016/j.ydbio.2010.08.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 08/07/2010] [Accepted: 08/10/2010] [Indexed: 10/19/2022]
Abstract
In Drosophila melanogaster, hypomorphic mutations in the gap gene giant (gt) have long been known to affect ecdysone titers resulting in developmental delay and the production of large (giant) larvae, pupae and adults. However, the mechanism by which gt regulates ecdysone production has remained elusive. Here we show that hypomorphic gt mutations lead to ecdysone deficiency and developmental delay by affecting the specification of the PG neurons that produce prothoracicotropic hormone (PTTH). The gt¹ hypomorphic mutation leads to random loss of PTTH production in one or more of the 4 PG neurons in the larval brain. In cases where PTTH production is lost in all four PG neurons, delayed development and giant larvae are produced. Since immunostaining shows no evidence for Gt expression in the PG neurons once PTTH production is detectable, it is unlikely that Gt directly regulates PTTH expression. Instead, we find that innervation of the prothoracic gland by the PG neurons is absent in gt hypomorphic larvae that do not express PTTH. In addition, PG neuron axon fasciculation is abnormal in many gt hypomorphic larvae. Since several other anteriorly expressed gap genes such as tailless and orthodenticle have previously been found to affect the fate of the cerebral labrum, a region of the brain that gives rise to the neuroendocrine cells that innervate the ring gland, we conclude that gt likely controls ecdysone production indirectly by contributing the peptidergic phenotype of the PTTH-producing neurons in the embryo.
Collapse
Affiliation(s)
- Arpan Ghosh
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | |
Collapse
|
273
|
Delanoue R, Slaidina M, Léopold P. The steroid hormone ecdysone controls systemic growth by repressing dMyc function in Drosophila fat cells. Dev Cell 2010; 18:1012-21. [PMID: 20627082 DOI: 10.1016/j.devcel.2010.05.007] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 02/11/2010] [Accepted: 03/23/2010] [Indexed: 12/31/2022]
Abstract
How steroid hormones shape animal growth remains poorly understood. In Drosophila, the main steroid hormone, ecdysone, limits systemic growth during juvenile development. Here we show that ecdysone controls animal growth rate by specifically acting on the fat body, an organ that retains endocrine and storage functions of the vertebrate liver and fat. We demonstrate that fat body-targeted loss of function of the Ecdysone receptor (EcR) increases dMyc expression and its cellular functions such as ribosome biogenesis. Moreover, changing dMyc levels in this tissue is sufficient to affect animal growth rate. Finally, the growth increase induced by silencing EcR in the fat body is suppressed by cosilencing dMyc. In conclusion, the present work reveals an unexpected function of dMyc in the systemic control of growth in response to steroid hormone signaling.
Collapse
Affiliation(s)
- Rénald Delanoue
- Institute of Developmental Biology and Cancer, University of Nice-Sophia Antipolis, CNRS, Parc Valrose, 06108 Nice, France
| | | | | |
Collapse
|
274
|
Kahsai L, Kapan N, Dircksen H, Winther ÅME, Nässel DR. Metabolic stress responses in Drosophila are modulated by brain neurosecretory cells that produce multiple neuropeptides. PLoS One 2010; 5:e11480. [PMID: 20628603 PMCID: PMC2900207 DOI: 10.1371/journal.pone.0011480] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 06/15/2010] [Indexed: 12/02/2022] Open
Abstract
In Drosophila, neurosecretory cells that release peptide hormones play a prominent role in the regulation of development, growth, metabolism, and reproduction. Several types of peptidergic neurosecretory cells have been identified in the brain of Drosophila with release sites in the corpora cardiaca and anterior aorta. We show here that in adult flies the products of three neuropeptide precursors are colocalized in five pairs of large protocerebral neurosecretory cells in two clusters (designated ipc-1 and ipc-2a): Drosophila tachykinin (DTK), short neuropeptide F (sNPF) and ion transport peptide (ITP). These peptides were detected by immunocytochemistry in combination with GFP expression driven by the enhancer trap Gal4 lines c929 and Kurs-6, both of which are expressed in ipc-1 and 2a cells. This mix of colocalized peptides with seemingly unrelated functions is intriguing and prompted us to initiate analysis of the function of the ten neurosecretory cells. We investigated the role of peptide signaling from large ipc-1 and 2a cells in stress responses by monitoring the effect of starvation and desiccation in flies with levels of DTK or sNPF diminished by RNA interference. Using the Gal4-UAS system we targeted the peptide knockdown specifically to ipc-1 and 2a cells with the c929 and Kurs-6 drivers. Flies with reduced DTK or sNPF levels in these cells displayed decreased survival time at desiccation and starvation, as well as increased water loss at desiccation. Our data suggest that homeostasis during metabolic stress requires intact peptide signaling by ipc-1 and 2a neurosecretory cells.
Collapse
Affiliation(s)
- Lily Kahsai
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | - Neval Kapan
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | | | | | - Dick R. Nässel
- Department of Zoology, Stockholm University, Stockholm, Sweden
- * E-mail:
| |
Collapse
|
275
|
Genes of the ecdysone biosynthesis pathway are regulated by the dATAC histone acetyltransferase complex in Drosophila. Mol Cell Biol 2010; 30:4254-66. [PMID: 20584983 DOI: 10.1128/mcb.00142-10] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Uncovering mechanisms that regulate ecdysone production is an important step toward understanding the regulation of insect metamorphosis and processes in steroid-related pathologies. We report here the transcriptome analysis of Drosophila melanogaster dAda2a and dAda3 mutants, in which subunits of the ATAC acetyltransferase complex are affected. In agreement with the fact that these mutations lead to lethality at the start of metamorphosis, both the ecdysone levels and the ecdysone receptor binding to polytene chromosomes are reduced in these flies. The cytochrome genes (spookier, phantom, disembodied, and shadow) involved in steroid conversion in the ring gland are downregulated, while the gene shade, which is involved in converting ecdysone into its active form in the periphery, is upregulated in these dATAC subunit mutants. Moreover, driven expression of dAda3 at the site of ecdysone synthesis partially rescues dAda3 mutants. Mutants of dAda2b, a subunit of the dSAGA histone acetyltransferase complex, do not share phenotype characteristics and RNA profile alterations with dAda2a mutants, indicating that the ecdysone biosynthesis genes are regulated by dATAC, but not by dSAGA. Thus, we provide one of the first examples of the coordinated regulation of a functionally linked set of genes by the metazoan-specific ATAC complex.
Collapse
|
276
|
Wei ZJ, Yu M, Tang SM, Yi YZ, Hong GY, Jiang ST. Transcriptional regulation of the gene for prothoracicotropic hormone in the silkworm, Bombyx mori. Mol Biol Rep 2010; 38:1121-7. [PMID: 20563654 DOI: 10.1007/s11033-010-0209-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 06/11/2010] [Indexed: 11/30/2022]
Abstract
Prothoracicotropic hormone (PTTH) is one of key players in regulation of insect growth, molting, metamorphosis, diapause, and is expressed specifically in the two pairs of lateral PTTH-producing neurosecretory cells in the brain. Analysis of cis-regulatory elements of the PTTH promoter might elucidate the regulatory mechanism controlling PTTH expression. In this study, the PTTH gene promoter of Bombyx mori (Bom-PTTH) was cloned and sequenced. The cis-regulatory elements in Bom-PTTH gene promoter were predicted using Matinspector software, including myocyte-specific enhancer factor 2, pre-B-cell leukemia homeobox 1, TATA box, etc. Transient transfection assays using a series of fragments linked to the luciferase reporter gene indicated that the fragment spanning -110 to +33 bp of the Bom-PTTH promoter showed high ability to support reporter gene expression, but the region of +34 to +192 bp and -512 to -111 bp repressed the promoter activity in the BmN and Bm5 cell lines. Electrophoretic mobility shift assays demonstrated that the nuclear protein could specifically bind to the region spanning -124 to -6 bp of the Bom-PTTH promoter. Furthermore, we observed that the nuclear protein could specifically bind to the -59 to -30 bp region of the Bom-PTTH promoter. A classical TATA box, TATATAA, localized at positions -47 to -41 bp, which is a potential site for interaction with TATA box binding protein (TBP). Mutation of this TATA box resulted in no distinct binding band. Taken together, TATA box was involved in regulation of PTTH gene expression in B. mori.
Collapse
Affiliation(s)
- Zhao-Jun Wei
- Department of Biotechnology, Hefei University of Technology, Hefei, 230009, People's Republic of China.
| | | | | | | | | | | |
Collapse
|
277
|
Niwa R, Namiki T, Ito K, Shimada-Niwa Y, Kiuchi M, Kawaoka S, Kayukawa T, Banno Y, Fujimoto Y, Shigenobu S, Kobayashi S, Shimada T, Katsuma S, Shinoda T. Non-molting glossy/shroud encodes a short-chain dehydrogenase/reductase that functions in the 'Black Box' of the ecdysteroid biosynthesis pathway. Development 2010; 137:1991-9. [PMID: 20501590 DOI: 10.1242/dev.045641] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In insects, the precise timing of molting and metamorphosis is strictly guided by a principal steroid hormone, ecdysone. Among the multiple conversion steps for synthesizing ecdysone from dietary cholesterol, the conversion of 7-dehydrocholesterol to 5beta-ketodiol, the so-called 'Black Box', is thought to be the important rate-limiting step. Although a number of genes essential for ecdysone synthesis have recently been revealed, much less is known about the genes that are crucial for functioning in the Black Box. Here we report on a novel ecdysteroidgenic gene, non-molting glossy (nm-g)/shroud (sro), which encodes a short-chain dehydrogenase/reductase. This gene was first isolated by positional cloning of the nm-g mutant of the silkworm Bombyx mori, which exhibits a low ecdysteroid titer and consequently causes a larval arrest phenotype. In the fruit fly, Drosophila melanogaster, the closest gene to nm-g is encoded by the sro locus, one of the Halloween mutant members that are characterized by embryonic ecdysone deficiency. The lethality of the sro mutant is rescued by the overexpression of either sro or nm-g genes, indicating that these two genes are orthologous. Both the nm-g and the sro genes are predominantly expressed in tissues producing ecdysone, such as the prothoracic glands and the ovaries. Furthermore, the phenotypes caused by the loss of function of these genes are restored by the application of ecdysteroids and their precursor 5beta-ketodiol, but not by cholesterol or 7-dehydrocholesterol. Altogether, we conclude that the Nm-g/Sro family protein is an essential enzyme for ecdysteroidogenesis working in the Black Box.
Collapse
Affiliation(s)
- Ryusuke Niwa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
278
|
Xiang Y, Liu Z, Huang X. br regulates the expression of the ecdysone biosynthesis gene npc1. Dev Biol 2010; 344:800-8. [PMID: 20621708 DOI: 10.1016/j.ydbio.2010.05.510] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 05/21/2010] [Accepted: 05/26/2010] [Indexed: 12/24/2022]
Abstract
The growth and metamorphosis of insects are regulated by ecdysteroid hormones produced in the ring gland. Ecdysone biosynthesis-related genes are both highly and specifically expressed in the ring gland. However, the intrinsic regulation of ecdysone biosynthesis has received little attention. Here we used the Drosophila npc1 gene to study the mechanism of ring gland-specific gene expression. npc1 is important for sterol trafficking in the ring gland during ecdysone biosynthesis. We have identified a conserved ring gland-specific cis-regulatory element (RSE) in the npc1 promoter using promoter fusion reporter analysis. Furthermore, genetic loss-of-function analysis and in vitro electrophoretic mobility shift assays revealed that the ecdysone early response gene broad complex (br) is a vital factor in the positive regulation of npc1 ring gland expression. Moreover, br also affects the ring gland expression of many other ecdysone biosynthetic genes as well as torso and InR, two key factors in the regulation of ecdysone biosynthesis. These results imply that ecdysone could potentially act through its early response gene br to achieve positive feedback regulation of ecdysone biosynthesis during development.
Collapse
Affiliation(s)
- Yanhui Xiang
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | | | | |
Collapse
|
279
|
Rhea JM, Wegener C, Bender M. The proprotein convertase encoded by amontillado (amon) is required in Drosophila corpora cardiaca endocrine cells producing the glucose regulatory hormone AKH. PLoS Genet 2010; 6:e1000967. [PMID: 20523747 PMCID: PMC2877730 DOI: 10.1371/journal.pgen.1000967] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 04/21/2010] [Indexed: 12/01/2022] Open
Abstract
Peptide hormones are potent signaling molecules that coordinate animal physiology, behavior, and development. A key step in activation of these peptide signals is their proteolytic processing from propeptide precursors by a family of proteases, the subtilisin-like proprotein convertases (PCs). Here, we report the functional dissection of amontillado (amon), which encodes the Drosophila homolog of the mammalian PC2 protein, using cell-type specific inactivation and rescue experiments, and we show that amon is required in the islet-like adipokinetic hormone (AKH)–producing cells that regulate sugar homeostasis. In Drosophila, AKH acts analogously to vertebrate glucagon to increase circulating sugar levels from energy stores, while insulin-like peptides (DILPs) act to decrease sugar levels. amon mutant larvae have significantly reduced hemolymph sugar levels, and thus phenocopy larvae where the AKH–producing cells in the corpora cardiaca have been ablated. Reduction of amon expression in these cells via cell-specific RNA inactivation also results in larvae with reduced sugar levels while expression of amon in AKH cells in an amon mutant background rescues hypoglycemia. Hypoglycemia in larvae resulting from amon RNA inactivation in the AKH cells can be rescued by global expression of the akh gene. Finally, mass spectrometric profiling shows that the production of mature AKH is inhibited in amon mutants. Our data indicate that amon function in the AKH cells is necessary to maintain normal sugar homeostasis, that amon functions upstream of akh, and that loss of mature AKH is correlated with loss of amon activity. These observations indicate that the AKH propeptide is a proteolytic target of the amon proprotein convertase and provide evidence for a conserved role of PC2 in processing metabolic peptide hormones. Peptide hormones are important signaling molecules that coordinate physiology, behavior, and development. A key step in production of peptide hormones is the proteolytic cleavage of larger inactive precursors by prohormone convertases (PCs). Studies in a variety of organisms, including humans, have shown that deficiencies in PC genes lead to complex and detrimental changes. We used fruitfly genetics to dissect the function of Drosophila PC2, encoded by the amon gene, in the regulation of carbohydrate metabolism. We found that amon is expressed in endocrine cells of the corpora cardiaca that produce the sugar-mobilizing adipokinetic hormone (AKH), a functional analog of vertebrate glucagon. Previous studies suggest that the AKH–producing cells are homologs of the glucagon-producing islet alpha-cells in the pancreas. We found that flies with amon deficiency had significantly reduced hemolymph (insect “blood”) sugar levels. Using cell-type specific inactivation and rescue experiments, we show that amon expression in the AKH cells is necessary and sufficient for normal sugar regulation. We also demonstrate that AKH production is inhibited in amon mutants. Our results indicate that amon is necessary to maintain normal hemolymph sugar levels by activating AKH and suggest a conservation of PC2 function in processing peptide hormones between flies and mammals.
Collapse
Affiliation(s)
- Jeanne M. Rhea
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
| | - Christian Wegener
- Emmy Noether Neuropeptide Group, Department of Animal Physiology, Philipps University, Marburg, Germany
| | - Michael Bender
- Department of Genetics, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
| |
Collapse
|
280
|
Montagne J, Lecerf C, Parvy JP, Bennion JM, Radimerski T, Ruhf ML, Zilbermann F, Vouilloz N, Stocker H, Hafen E, Kozma SC, Thomas G. The nuclear receptor DHR3 modulates dS6 kinase-dependent growth in Drosophila. PLoS Genet 2010; 6:e1000937. [PMID: 20463884 PMCID: PMC2865512 DOI: 10.1371/journal.pgen.1000937] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 04/02/2010] [Indexed: 12/25/2022] Open
Abstract
S6 kinases (S6Ks) act to integrate nutrient and insulin signaling pathways and, as such, function as positive effectors in cell growth and organismal development. However, they also have been shown to play a key role in limiting insulin signaling and in mediating the autophagic response. To identify novel regulators of S6K signaling, we have used a Drosophila-based, sensitized, gain-of-function genetic screen. Unexpectedly, one of the strongest enhancers to emerge from this screen was the nuclear receptor (NR), Drosophila hormone receptor 3 (DHR3), a critical constituent in the coordination of Drosophila metamorphosis. Here we demonstrate that DHR3, through dS6K, also acts to regulate cell-autonomous growth. Moreover, we show that the ligand-binding domain (LBD) of DHR3 is essential for mediating this response. Consistent with these findings, we have identified an endogenous DHR3 isoform that lacks the DBD. These results provide the first molecular link between the dS6K pathway, critical in controlling nutrient-dependent growth, and that of DHR3, a major mediator of ecdysone signaling, which, acting together, coordinate metamorphosis.
Collapse
Affiliation(s)
- Jacques Montagne
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Centre de Génétique Moléculaire, CNRS UPR 2167, Gif-sur-Yvette, France
- Université Paris-Sud, Orsay, France
- Université Pierre et Marie Curie-Paris 6, Paris, France
- * E-mail: (JM); (GT)
| | - Caroline Lecerf
- Centre de Génétique Moléculaire, CNRS UPR 2167, Gif-sur-Yvette, France
- Université Paris-Sud, Orsay, France
- Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Jean-Philippe Parvy
- Centre de Génétique Moléculaire, CNRS UPR 2167, Gif-sur-Yvette, France
- Université Paris-Sud, Orsay, France
- Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Janis M. Bennion
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Thomas Radimerski
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Marie-Laure Ruhf
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
| | | | - Nicole Vouilloz
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Hugo Stocker
- ETH, Institut für Molekulare Systembiologie, Zürich, Switzerland
| | - Ernst Hafen
- ETH, Institut für Molekulare Systembiologie, Zürich, Switzerland
| | - Sara C. Kozma
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - George Thomas
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail: (JM); (GT)
| |
Collapse
|
281
|
Halme A, Cheng M, Hariharan IK. Retinoids regulate a developmental checkpoint for tissue regeneration in Drosophila. Curr Biol 2010; 20:458-63. [PMID: 20189388 PMCID: PMC2847081 DOI: 10.1016/j.cub.2010.01.038] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 01/11/2010] [Accepted: 01/11/2010] [Indexed: 10/19/2022]
Abstract
Damage to Drosophila imaginal discs elicits a robust regenerative response from the surviving tissue [1-4]. However, as in other organisms, developmental progression and differentiation can restrict the regenerative capacity of Drosophila tissues. Experiments in Drosophila and other holometabolous insects have demonstrated that either damage to imaginal tissues [5, 6] or transplantation of a damaged imaginal disc [7, 8] delays the onset of metamorphosis. Therefore, in Drosophila there appears to be a mechanism that senses tissue damage and extends the larval phase to coordinate tissue regeneration with the overall developmental program of the organism. However, how such a pathway functions remains unknown. Here we demonstrate that a developmental checkpoint extends larval growth after imaginal disc damage by inhibiting the transcription of the gene encoding PTTH, a neuropeptide that promotes the release of the steroid hormone ecdysone. Using a genetic screen, we identify a previously unsuspected role for retinoid biosynthesis in regulating PTTH expression and delaying development in response to tissue damage. Retinoid signaling plays an important but poorly defined role in several vertebrate regeneration models [9-11]. Our findings demonstrate that retinoid biosynthesis in Drosophila is important for the maintenance of a condition that is permissive for regenerative growth.
Collapse
Affiliation(s)
- Adrian Halme
- Department of Cell and Developmental Biology, University of California, Berkeley, 365 LSA, MC 3200, Berkeley, CA 94703
| | - Michelle Cheng
- Department of Cell and Developmental Biology, University of California, Berkeley, 365 LSA, MC 3200, Berkeley, CA 94703
| | - Iswar K. Hariharan
- Department of Cell and Developmental Biology, University of California, Berkeley, 365 LSA, MC 3200, Berkeley, CA 94703
| |
Collapse
|
282
|
Marchal E, Vandersmissen HP, Badisco L, Van de Velde S, Verlinden H, Iga M, Van Wielendaele P, Huybrechts R, Simonet G, Smagghe G, Vanden Broeck J. Control of ecdysteroidogenesis in prothoracic glands of insects: a review. Peptides 2010; 31:506-19. [PMID: 19723550 DOI: 10.1016/j.peptides.2009.08.020] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 08/21/2009] [Accepted: 08/21/2009] [Indexed: 01/13/2023]
Abstract
The very first step in the study of the endocrine control of insect molting was taken in 1922. Stefan Kopec characterized a factor in the brain of the gypsy moth, Lymantria dispar which appeared to be essential for metamorphosis. This factor was later identified as the neuropeptide prothoracicotropic hormone (PTTH), the first discovery of a series of factors involved in the regulation of ecdysteroid biosynthesis in insects. It is now accepted that PTTH is the most important regulator of prothoracic gland (PG) ecdysteroidogenesis. The periodic increases in ecdysteroid titer necessary for insect development can basically be explained by the episodic activation of the PGs by PTTH. However, since the characterization of the prothoracicostatic hormone (PTSH), it has become clear that in addition to 'tropic factors', also 'static factors', which are responsible for the 'fine-tuning' of the hemolymph ecdysteroid titer, are at play. Many of these regulatory factors are peptides originating from the brain, but also other, extracerebral factors both of peptidic and non-peptidic nature are able to affect PG ecdysteroidogenesis, such as the 'classic' insect hormones, juvenile hormone (JH) and the molting hormone (20E) itself. The complex secretory pattern of ecdysteroids as observed in vivo is the result of the delicate balance and interplay between these ecdysiotropic and ecdysiostatic factors.
Collapse
Affiliation(s)
- Elisabeth Marchal
- Department of Animal Physiology and Neurobiology, K.U. Leuven, Naamsestraat 59, 3000 Leuven, Belgium
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
283
|
Inosaki A, Yasuda A, Shinada T, Ohfune Y, Numata H, Shiga S. Mass spectrometric analysis of peptides in brain neurosecretory cells and neurohemal organs in the adult blowfly, Protophormia terraenovae. Comp Biochem Physiol A Mol Integr Physiol 2010; 155:190-9. [DOI: 10.1016/j.cbpa.2009.10.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 10/27/2009] [Accepted: 10/27/2009] [Indexed: 01/03/2023]
|
284
|
Bombyx prothoracicostatic peptides activate the sex peptide receptor to regulate ecdysteroid biosynthesis. Proc Natl Acad Sci U S A 2010; 107:2060-5. [PMID: 20133850 DOI: 10.1073/pnas.0907471107] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Insect molting and metamorphosis are induced by steroid hormones named ecdysteroids, whose production is regulated by various neuropeptides. We cloned the gene and analyzed the expression of the prothoracicostatic peptide, a unique neuropeptide shown to suppress the production of ecdysteroids in the prothoracic gland of the silkworm, Bombyx mori. We also characterized a Bombyx G protein-coupled receptor, which has previously been identified as an ortholog of the Drosophila sex peptide receptor, as a functional prothoracicostatic peptide receptor. This receptor responded specifically to the prothoracicostatic peptides when examined using a heterologous expression system. The receptor was highly expressed in the prothoracic gland on the day before each larval and pupal ecdysis, when prothoracicostatic peptides are synthesized at a high level in the epiproctodeal glands. These results suggest that the sex peptide receptor functions as a prothoracicostatic peptide receptor in Bombyx and that the peripheral neurosecretory cells as well as the central neuroendocrine system play stage-specific roles in regulating ecdysteroidogenesis.
Collapse
|
285
|
Rewitz KF, Yamanaka N, Gilbert LI, O'Connor MB. The Insect Neuropeptide PTTH Activates Receptor Tyrosine Kinase Torso to Initiate Metamorphosis. Science 2009; 326:1403-5. [DOI: 10.1126/science.1176450] [Citation(s) in RCA: 264] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
286
|
Spindler KD, Hönl C, Tremmel C, Braun S, Ruff H, Spindler-Barth M. Ecdysteroid hormone action. Cell Mol Life Sci 2009; 66:3837-50. [PMID: 19669094 PMCID: PMC11115491 DOI: 10.1007/s00018-009-0112-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 07/16/2009] [Accepted: 07/16/2009] [Indexed: 01/05/2023]
Abstract
Several reviews devoted to various aspects of ecdysone research have been published during the last few years. Therefore, this article concentrates mainly on the considerable progress in ecdysone research observed recently, and will cover the results obtained during the last 2 years. The main emphasis is put on the molecular mode of ecdysteroid receptor-mediated hormone action. Two examples of interaction with other hormonal signalling pathways are described, namely crosstalk with juvenile hormone and insulin. Some selected, recently investigated examples of the multitude of hormonal responses are described. Finally, ecological aspects and some practical applications are discussed.
Collapse
Affiliation(s)
- Klaus-Dieter Spindler
- Institute of General Zoology and Endocrinology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | | | | | | | | | | |
Collapse
|
287
|
Parrish JZ, Xu P, Kim CC, Jan LY, Jan YN. The microRNA bantam functions in epithelial cells to regulate scaling growth of dendrite arbors in drosophila sensory neurons. Neuron 2009; 63:788-802. [PMID: 19778508 DOI: 10.1016/j.neuron.2009.08.006] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2009] [Revised: 06/30/2009] [Accepted: 08/11/2009] [Indexed: 12/19/2022]
Abstract
In addition to establishing dendritic coverage of the receptive field, neurons need to adjust their dendritic arbors to match changes of the receptive field. Here, we show that dendrite arborization (da) sensory neurons establish dendritic coverage of the body wall early in Drosophila larval development and then grow in precise proportion to their substrate, the underlying body wall epithelium, as the larva more than triples in length. This phenomenon, referred to as scaling growth of dendrites, requires the function of the microRNA (miRNA) bantam (ban) in the epithelial cells rather than the da neurons themselves. We further show that ban in epithelial cells dampens Akt kinase activity in adjacent neurons to influence dendrite growth. This signaling between epithelial cells and neurons receiving sensory input from the body wall synchronizes their growth to ensure proper dendritic coverage of the receptive field.
Collapse
Affiliation(s)
- Jay Z Parrish
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | | | | | | | | |
Collapse
|
288
|
Inositol 1,4,5- trisphosphate receptor function in Drosophila insulin producing cells. PLoS One 2009; 4:e6652. [PMID: 19680544 PMCID: PMC2721413 DOI: 10.1371/journal.pone.0006652] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 07/13/2009] [Indexed: 01/26/2023] Open
Abstract
The Inositol 1,4,5- trisphosphate receptor (InsP3R) is an intracellular ligand gated channel that releases calcium from intracellular stores in response to extracellular signals. To identify and understand physiological processes and behavior that depends on the InsP3 signaling pathway at a systemic level, we are studying Drosophila mutants for the InsP3R (itpr) gene. Here, we show that growth defects precede larval lethality and both are a consequence of the inability to feed normally. Moreover, restoring InsP3R function in insulin producing cells (IPCs) in the larval brain rescues the feeding deficit, growth and lethality in the itpr mutants to a significant extent. We have previously demonstrated a critical requirement for InsP3R activity in neuronal cells, specifically in aminergic interneurons, for larval viability. Processes from the IPCs and aminergic domain are closely apposed in the third instar larval brain with no visible cellular overlap. Ubiquitous depletion of itpr by dsRNA results in feeding deficits leading to larval lethality similar to the itpr mutant phenotype. However, when itpr is depleted specifically in IPCs or aminergic neurons, the larvae are viable. These data support a model where InsP3R activity in non-overlapping neuronal domains independently rescues larval itpr phenotypes by non-cell autonomous mechanisms.
Collapse
|
289
|
Rewitz KF, Larsen MR, Lobner-Olesen A, Rybczynski R, O'Connor MB, Gilbert LI. A phosphoproteomics approach to elucidate neuropeptide signal transduction controlling insect metamorphosis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2009; 39:475-483. [PMID: 19422916 DOI: 10.1016/j.ibmb.2009.04.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 04/16/2009] [Accepted: 04/17/2009] [Indexed: 05/27/2023]
Abstract
In insects, the neuropeptide prothoracicotropic hormone (PTTH) stimulates production of ecdysone (E) in the prothoracic glands (PGs). E is the precursor of the principal steroid hormone, 20-hydroxyecdysone (20E), that is responsible for eliciting molting and metamorphosis. In this study, we used quantitative phosphoproteomics to investigate signal transduction events initiated by PTTH. We identified Spook (CYP307A1), a suspected rate-limiting enzyme for E biosynthesis, and components of the mitogen-activated protein kinase (MAPK) pathway, as major phosphorylation targets of PTTH signaling. Further, proteins not previously linked to PTTH and ecdysone biosynthesis were identified as targets of PTTH signaling. These include proteins involved in signal transduction, endosomal trafficking, constituents of the cytoskeleton and regulators of transcription and translation. Our screen shows that PTTH likely stimulates E production by activation of Spook, an integral enzyme in the E biosynthetic pathway. This directly connects PTTH signaling to the pathway that produces E. A new mechanism for regulation of E biosynthesis in insects is proposed.
Collapse
Affiliation(s)
- Kim F Rewitz
- The Department of Science, Systems and Models, Roskilde University, 4000 Roskilde, Denmark.
| | | | | | | | | | | |
Collapse
|
290
|
Liu Y, Sheng Z, Liu H, Wen D, He Q, Wang S, Shao W, Jiang RJ, An S, Sun Y, Bendena WG, Wang J, Gilbert LI, Wilson TG, Song Q, Li S. Juvenile hormone counteracts the bHLH-PAS transcription factors MET and GCE to prevent caspase-dependent programmed cell death in Drosophila. Development 2009; 136:2015-25. [DOI: 10.1242/dev.033712] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Juvenile hormone (JH) regulates many developmental and physiological events in insects, but its molecular mechanism remains conjectural. Here we report that genetic ablation of the corpus allatum cells of the Drosophilaring gland (the JH source) resulted in JH deficiency, pupal lethality and precocious and enhanced programmed cell death (PCD) of the larval fat body. In the fat body of the JH-deficient animals, Dronc and Drice,two caspase genes that are crucial for PCD induced by the molting hormone 20-hydroxyecdysone (20E), were significantly upregulated. These results demonstrated that JH antagonizes 20E-induced PCD by restricting the mRNA levels of Dronc and Drice. The antagonizing effect of JH on 20E-induced PCD in the fat body was further confirmed in the JH-deficient animals by 20E treatment and RNA interference of the 20E receptor EcR. Moreover, MET and GCE, the bHLH-PAS transcription factors involved in JH action, were shown to induce PCD by upregulating Droncand Drice. In the Met- and gce-deficient animals, Dronc and Drice were downregulated, whereas in the Met-overexpression fat body, Dronc and Drice were significantly upregulated leading to precocious and enhanced PCD, and this upregulation could be suppressed by application of the JH agonist methoprene. For the first time, we demonstrate that JH counteracts MET and GCE to prevent caspase-dependent PCD in controlling fat body remodeling and larval-pupal metamorphosis in Drosophila.
Collapse
Affiliation(s)
- Ying Liu
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Zhentao Sheng
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hanhan Liu
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Di Wen
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Qianyu He
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Sheng Wang
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Wei Shao
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Rong-Jing Jiang
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Shiheng An
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211,USA
| | - Yaning Sun
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211,USA
| | - William G. Bendena
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6,Canada
| | - Jian Wang
- Department of Entomology, University of Maryland, College Park, MD 20742,USA
| | - Lawrence I. Gilbert
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599,USA
| | - Thomas G. Wilson
- Department of Entomology, Ohio State University, Columbus, OH 43210,USA
| | - Qisheng Song
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211,USA
| | - Sheng Li
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| |
Collapse
|
291
|
Park D, Taghert PH. Peptidergic neurosecretory cells in insects: organization and control by the bHLH protein DIMMED. Gen Comp Endocrinol 2009; 162:2-7. [PMID: 19135054 DOI: 10.1016/j.ygcen.2008.12.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Revised: 11/19/2008] [Accepted: 12/10/2008] [Indexed: 11/15/2022]
Abstract
This review considers evidence that defines a role for the transcription factor DIMMED in the regulation of insect neurosecretory cells. Genetic anatomical and molecular data all suggest DIMMED is a dedicated controller of the regulated secretory pathway. DIMM is normally expressed within diverse neuropeptide-expressing cells and appears highly correlated with a neurosecretory cell fate. Loss of DIMM is associated with deficits in display of neuropeptides and neuropeptide-associated enzymes. Gain of DIMM promotes such display in peptidergic cells and can confer such neurosecretory properties onto conventional neurons. We review models proposed to explain how DIMMED regulates these essential cellular properties.
Collapse
Affiliation(s)
- Dongkook Park
- Department of Anatomy & Neurobiology, Washington University Medical School, 660 South Euclid Avenue, Saint Louis, MO 63110, USA.
| | | |
Collapse
|
292
|
Huang X, Warren JT, Gilbert LI. New players in the regulation of ecdysone biosynthesis. J Genet Genomics 2009; 35:1-10. [PMID: 18222403 DOI: 10.1016/s1673-8527(08)60001-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 11/24/2007] [Accepted: 11/24/2007] [Indexed: 02/04/2023]
Abstract
Insect ecdysone steroid hormone regulates major developmental transitions, such as molting and metamorphosis. The production of ecdysone correlates well with the timing of these transitions. Finding out how the ecdysone biosynthesis is regulated is crucial to fully understand these sophisticated developmental switches. Here we summarized recent findings in the regulation of ecdysone biosynthesis from the aspects of cell signaling, key biosynthetic enzymes and substrate cholesterol trafficking.
Collapse
Affiliation(s)
- Xun Huang
- Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
| | | | | |
Collapse
|
293
|
Walkiewicz MA, Stern M. Increased insulin/insulin growth factor signaling advances the onset of metamorphosis in Drosophila. PLoS One 2009; 4:e5072. [PMID: 19352497 PMCID: PMC2662422 DOI: 10.1371/journal.pone.0005072] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Accepted: 02/22/2009] [Indexed: 12/21/2022] Open
Abstract
Mechanisms by which attainment of specific body sizes trigger developmental transitions to adulthood (e.g. puberty or metamorphosis) are incompletely understood. In Drosophila, metamorphosis is triggered by ecdysone synthesis from the prothoracic gland (PG), whereas growth rate is increased by insulin/insulin growth factor signalling (IIS). Transgene-induced activation of PI3K, the major effector of IIS, within the PG advances the onset of metamorphosis via precocious ecdysone synthesis, raising the possibility that IIS triggers metamorphosis via PI3K activation in the PG. Here we show that blocking the protein kinase A (PKA) pathway in the insulin producing cells (IPCs) increases IIS. This increased IIS increases larval growth rate and also advances the onset of metamorphosis, which is accompanied by precocious ecdysone synthesis and increased transcription of at least one ecdysone biosynthetic gene. Our observations suggest that IIS is regulated by PKA pathway activity in the IPCs. In addition, taken together with previous findings, our observations are consistent with the possibility that, in Drosophila, attainment of a specific body size triggers metamorphosis via the IIS-mediated activation of PI3K and hence ecdysone synthesis in the PG.
Collapse
Affiliation(s)
- Magdalena A Walkiewicz
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas, United States of America.
| | | |
Collapse
|
294
|
Pentek J, Parker L, Wu A, Arora K. Follistatin preferentially antagonizes activin rather than BMP signaling inDrosophila. Genesis 2009; 47:261-73. [DOI: 10.1002/dvg.20486] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
295
|
A basic-HLH transcription factor, HLH54F, is highly expressed in the prothoracic gland in the silkworm Bombyx mori and the fruit fly Drosophila melanogaster. Biosci Biotechnol Biochem 2009; 73:762-5. [PMID: 19270399 DOI: 10.1271/bbb.80737] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We describe our findings on HLH54F, a basic helix-loop-helix transcription factor gene that was highly expressed in the prothoracic gland, an organ producing the insect steroid ecdysone. HLH54F was uncovered by the use of an expressed sequence tag database of the silkworm Bombyx mori. It was also highly expressed in the prothoracic gland of the fruit fly Drosophila melanogaster.
Collapse
|
296
|
Hamanaka Y, Tanaka S, Numata H, Shiga S. Morphological Characterization of Neurons Projecting to the Ring Gland in the Larval Blow Fly,Protophormia terraenovae. Zoolog Sci 2009; 26:227-37. [DOI: 10.2108/zsj.26.227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
297
|
Toivonen JM, Partridge L. Endocrine regulation of aging and reproduction in Drosophila. Mol Cell Endocrinol 2009; 299:39-50. [PMID: 18682271 DOI: 10.1016/j.mce.2008.07.005] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 04/10/2008] [Accepted: 07/03/2008] [Indexed: 12/19/2022]
Abstract
Hormonal signals can modulate lifespan and reproductive capacity across the animal kingdom. The use of model organisms such as worms, flies and mice has been fundamentally important for aging research in the discovery of genetic alterations that can extend healthy lifespan. The effects of mutations in the insulin and insulin-like growth factor-like signaling (IIS) pathways are evolutionarily conserved in that they can increase lifespan in all three animal models. Additionally, steroids and other lipophilic signaling molecules modulate lifespan in diverse organisms. Here we shall review how major hormonal pathways in the fruit fly Drosophila melanogaster interact to influence reproductive capacity and aging.
Collapse
Affiliation(s)
- Janne M Toivonen
- Institute of Healthy Aging, UCL Research Department of Genetics, Environment and Evolution, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK.
| | | |
Collapse
|
298
|
Cranna N, Quinn L. Impact of steroid hormone signals on Drosophila cell cycle during development. Cell Div 2009; 4:3. [PMID: 19154610 PMCID: PMC2647916 DOI: 10.1186/1747-1028-4-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 01/20/2009] [Indexed: 11/30/2022] Open
Abstract
Metamorphosis of Drosophila involves proliferation, differentiation and death of larval tissues in order to form the adult fly. The major steroid hormone implicated in the larval-pupal transition and adult tissue modelling is ecdysone. Previous reviews have draw together studies connecting ecdysone signaling to the processes of apoptosis and differentiation. Here we discuss those reports connecting the ecdysone pulse to developmentally regulated cell cycle progression.
Collapse
Affiliation(s)
- Nicola Cranna
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville 3010, Melbourne, Australia.
| | | |
Collapse
|
299
|
Abstract
In this issue of Developmental Cell, Layalle et al. reveal new insights into how nutrition controls body size in Drosophila. Nutrition specifically affects the activity of target of rapamycin (TOR) in the prothoracic gland. Under low-nutrition conditions, TOR suppresses ecdysone secretion--which otherwise terminates larval development--thereby prolonging growth and allowing larvae to still attain a near-normal body size.
Collapse
|
300
|
Cruz J, Nieva C, Mané-Padrós D, Martín D, Bellés X. Nuclear receptor BgFTZ-F1 regulates molting and the timing of ecdysteroid production during nymphal development in the hemimetabolous insectBlattella germanica. Dev Dyn 2008; 237:3179-91. [DOI: 10.1002/dvdy.21728] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
|