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Steinmetz EL, Noh S, Klöppel C, Fuhr MF, Bach N, Raffael ME, Hildebrandt K, Wittling F, Jann D, Walldorf U. Generation of Mutants from the 57B Region of Drosophila melanogaster. Genes (Basel) 2023; 14:2047. [PMID: 38002990 PMCID: PMC10671637 DOI: 10.3390/genes14112047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
The 57B region of Drosophila melanogaster includes a cluster of the three homeobox genes orthopedia (otp), Drosophila Retinal homeobox (DRx), and homeobrain (hbn). In an attempt to isolate mutants for these genes, we performed an EMS mutagenesis and isolated lethal mutants from the 57B region, among them mutants for otp, DRx, and hbn. With the help of two newly generated deletions from the 57B region, we mapped additional mutants to specific chromosomal intervals and identified several of these mutants from the 57B region molecularly. In addition, we generated mutants for CG15651 and RIC-3 by gene targeting and mutants for the genes CG9344, CG15649, CG15650, and ND-B14.7 using the CRISPR/Cas9 system. We determined the lethality period during development for most isolated mutants. In total, we analysed alleles from nine different genes from the 57B region of Drosophila, which could now be used to further explore the functions of the corresponding genes in the future.
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Affiliation(s)
- Eva Louise Steinmetz
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
- Zoology & Physiology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building B2.1, D-66123 Saarbrücken, Germany
| | - Sandra Noh
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Christine Klöppel
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Martin F. Fuhr
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Nicole Bach
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Mona Evelyn Raffael
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Kirsten Hildebrandt
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
| | - Fabienne Wittling
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarland University, Building E8.1, D-66123 Saarbrücken, Germany
| | - Doris Jann
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
- Medical Biochemistry & Molecular Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 45.2, D-66421 Homburg, Germany
| | - Uwe Walldorf
- Developmental Biology, ZHMB (Center of Human and Molecular Biology), Saarland University, Building 61, D-66421 Homburg, Germany
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2
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Scott H, Novikov B, Ugur B, Allen B, Mertsalov I, Monagas-Valentin P, Koff M, Baas Robinson S, Aoki K, Veizaj R, Lefeber DJ, Tiemeyer M, Bellen H, Panin V. Glia-neuron coupling via a bipartite sialylation pathway promotes neural transmission and stress tolerance in Drosophila. eLife 2023; 12:e78280. [PMID: 36946697 PMCID: PMC10110239 DOI: 10.7554/elife.78280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 03/16/2023] [Indexed: 03/23/2023] Open
Abstract
Modification by sialylated glycans can affect protein functions, underlying mechanisms that control animal development and physiology. Sialylation relies on a dedicated pathway involving evolutionarily conserved enzymes, including CMP-sialic acid synthetase (CSAS) and sialyltransferase (SiaT) that mediate the activation of sialic acid and its transfer onto glycan termini, respectively. In Drosophila, CSAS and DSiaT genes function in the nervous system, affecting neural transmission and excitability. We found that these genes function in different cells: the function of CSAS is restricted to glia, while DSiaT functions in neurons. This partition of the sialylation pathway allows for regulation of neural functions via a glia-mediated control of neural sialylation. The sialylation genes were shown to be required for tolerance to heat and oxidative stress and for maintenance of the normal level of voltage-gated sodium channels. Our results uncovered a unique bipartite sialylation pathway that mediates glia-neuron coupling and regulates neural excitability and stress tolerance.
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Affiliation(s)
- Hilary Scott
- Department of Biochemistry and Biophysics, Texas A&M UniversityCollege StationUnited States
| | - Boris Novikov
- Department of Biochemistry and Biophysics, Texas A&M UniversityCollege StationUnited States
| | - Berrak Ugur
- Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, and Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Brooke Allen
- Department of Biochemistry and Biophysics, Texas A&M UniversityCollege StationUnited States
| | - Ilya Mertsalov
- Department of Biochemistry and Biophysics, Texas A&M UniversityCollege StationUnited States
| | - Pedro Monagas-Valentin
- Department of Biochemistry and Biophysics, Texas A&M UniversityCollege StationUnited States
| | - Melissa Koff
- Department of Biochemistry and Biophysics, Texas A&M UniversityCollege StationUnited States
| | - Sarah Baas Robinson
- Complex Carbohydrate Research Center, University of GeorgiaAthensUnited States
| | - Kazuhiro Aoki
- Complex Carbohydrate Research Center, University of GeorgiaAthensUnited States
| | - Raisa Veizaj
- Translational Metabolic Laboratory, Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical CenterNijmegenNetherlands
| | - Dirk J Lefeber
- Translational Metabolic Laboratory, Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical CenterNijmegenNetherlands
| | - Michael Tiemeyer
- Complex Carbohydrate Research Center, University of GeorgiaAthensUnited States
| | - Hugo Bellen
- Departments of Molecular and Human Genetics and Neuroscience, Baylor College of Medicine, and Jan and Dan Duncan Neurological Research Institute, Texas Children’s HospitalHoustonUnited States
| | - Vladislav Panin
- Department of Biochemistry and Biophysics, Texas A&M UniversityCollege StationUnited States
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3
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Lin S. The making of the Drosophila mushroom body. Front Physiol 2023; 14:1091248. [PMID: 36711013 PMCID: PMC9880076 DOI: 10.3389/fphys.2023.1091248] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 01/02/2023] [Indexed: 01/14/2023] Open
Abstract
The mushroom body (MB) is a computational center in the Drosophila brain. The intricate neural circuits of the mushroom body enable it to store associative memories and process sensory and internal state information. The mushroom body is composed of diverse types of neurons that are precisely assembled during development. Tremendous efforts have been made to unravel the molecular and cellular mechanisms that build the mushroom body. However, we are still at the beginning of this challenging quest, with many key aspects of mushroom body assembly remaining unexplored. In this review, I provide an in-depth overview of our current understanding of mushroom body development and pertinent knowledge gaps.
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Calderón-Rosete G, González-Barrios JA, Piña-Leyva C, Moreno-Sandoval HN, Lara-Lozano M, Rodríguez-Sosa L. Transcriptional identification of genes light-interacting in the extraretinal photoreceptors of the crayfish Procambarusclarkii. Zookeys 2021; 1072:107-127. [PMID: 34899009 PMCID: PMC8626408 DOI: 10.3897/zookeys.1072.73075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/21/2021] [Indexed: 11/12/2022] Open
Abstract
Crayfish serve as a model for studying the effect of environmental lighting on locomotor activity and neuroendocrine functions. The effects of light on this organism are mediated differentially by retinal and extraretinal photoreceptors located in the cerebroid ganglion and the pleonal nerve cord. However, some molecular aspects of the phototransduction cascade in the pleonal extraretinal photoreceptors remain unknown. In this study, transcriptome data from the pleonal nerve cord of the crayfish Procambarusclarkii (Girard,1852) were analyzed to identify transcripts that potentially interact with phototransduction process. The Illumina MiSeq System and the pipeline Phylogenetically Informed Annotation (PIA) were employed, which places uncharacterized genes into pre-calculated phylogenies of gene families. Here, for the first time 62 transcripts identified from the pleonal nerve cord that are related to light-interacting pathways are reported; they can be classified into the following 11 sets: 1) retinoid pathway in vertebrates and invertebrates, 2) photoreceptor specification, 3) rhabdomeric phototransduction, 4) opsins 5) ciliary phototransduction, 6) melanin synthesis, 7) pterin synthesis, 8) ommochrome synthesis, 9) heme synthesis, 10) diurnal clock, and 11) crystallins. Moreover, this analysis comparing the sequences located on the pleonal nerve cord to eyestalk sequences reported in other studies reveals 94-100% similarity between the 55 common proteins identified. These results show that both retinal and pleonal non-visual photoreceptors in the crayfish equally expressed the transcripts involved in light detection. Moreover, they suggest that the genes related to ocular and extraocular light perception in the crayfish P.clarkii use biosynthesis pathways and phototransduction cascades commons.
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Affiliation(s)
- Gabina Calderón-Rosete
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, C. P. 04510, MéxicoUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
| | - Juan Antonio González-Barrios
- Laboratorio de Medicina Genómica, Hospital Regional “Primero de Octubre” ISSSTE, 07300, MéxicoLaboratorio de Medicina GenómicaCiudad de MéxicoMexico
| | - Celia Piña-Leyva
- Laboratorio de Medicina Genómica, Hospital Regional “Primero de Octubre” ISSSTE, 07300, MéxicoLaboratorio de Medicina GenómicaCiudad de MéxicoMexico
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y Estudios Avanzados, 07360, MéxicoCentro de Investigación y Estudios AvanzadosCiudad de MéxicoMexico
| | - Hayde Nallely Moreno-Sandoval
- Laboratorio de Medicina Genómica, Hospital Regional “Primero de Octubre” ISSSTE, 07300, MéxicoLaboratorio de Medicina GenómicaCiudad de MéxicoMexico
| | - Manuel Lara-Lozano
- Laboratorio de Medicina Genómica, Hospital Regional “Primero de Octubre” ISSSTE, 07300, MéxicoLaboratorio de Medicina GenómicaCiudad de MéxicoMexico
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y Estudios Avanzados, 07360, MéxicoCentro de Investigación y Estudios AvanzadosCiudad de MéxicoMexico
| | - Leonardo Rodríguez-Sosa
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, C. P. 04510, MéxicoUniversidad Nacional Autónoma de MéxicoCiudad de MéxicoMexico
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5
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Klöppel C, Hildebrandt K, Kolb D, Fürst N, Bley I, Karlowatz RJ, Walldorf U. Functional analysis of enhancer elements regulating the expression of the Drosophila homeodomain transcription factor DRx by gene targeting. Hereditas 2021; 158:42. [PMID: 34736520 PMCID: PMC8569992 DOI: 10.1186/s41065-021-00210-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/18/2021] [Indexed: 11/17/2022] Open
Abstract
Background The Drosophila brain is an ideal model system to study stem cells, here called neuroblasts, and the generation of neural lineages. Many transcriptional activators are involved in formation of the brain during the development of Drosophila melanogaster. The transcription factor Drosophila Retinal homeobox (DRx), a member of the 57B homeobox gene cluster, is also one of these factors for brain development. Results In this study a detailed expression analysis of DRx in different developmental stages was conducted. We show that DRx is expressed in the embryonic brain in the protocerebrum, in the larval brain in the DM and DL lineages, the medulla and the lobula complex and in the central complex of the adult brain. We generated a DRx enhancer trap strain by gene targeting and reintegration of Gal4, which mimics the endogenous expression of DRx. With the help of eight existing enhancer-Gal4 strains and one made by our group, we mapped various enhancers necessary for the expression of DRx during all stages of brain development from the embryo to the adult. We made an analysis of some larger enhancer regions by gene targeting. Deletion of three of these enhancers showing the most prominent expression patterns in the brain resulted in specific temporal and spatial loss of DRx expression in defined brain structures. Conclusion Our data show that DRx is expressed in specific neuroblasts and defined neural lineages and suggest that DRx is another important factor for Drosophila brain development. Supplementary Information The online version contains supplementary material available at 10.1186/s41065-021-00210-z.
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Affiliation(s)
- Christine Klöppel
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
| | - Kirsten Hildebrandt
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
| | - Dieter Kolb
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
| | - Nora Fürst
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany.,Present address: Genetics/Epigenetics, Saarland University, Building A2.4, 66123, Saarbrücken, Germany
| | - Isabelle Bley
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany.,Present address: Research Institute Children's Cancer Center Hamburg, Building N63, Martinistr. 52, 20251, Hamburg, Germany
| | | | - Uwe Walldorf
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany.
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6
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Hildebrandt K, Kübel S, Minet M, Fürst N, Klöppel C, Steinmetz E, Walldorf U. Enhancer analysis of the Drosophila zinc finger transcription factor Earmuff by gene targeting. Hereditas 2021; 158:41. [PMID: 34732265 PMCID: PMC8567707 DOI: 10.1186/s41065-021-00209-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/08/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Many transcription factors are involved in the formation of the brain during the development of Drosophila melanogaster. The transcription factor Earmuff (Erm), a member of the forebrain embryonic zinc finger family (Fezf), is one of these important factors for brain development. One major function of Earmuff is the regulation of proliferation within type II neuroblast lineages in the brain; here, Earmuff is expressed in intermediate neural progenitor cells (INPs) and balances neuronal differentiation versus stem cell maintenance. Erm expression during development is regulated by several enhancers. RESULTS In this work we show a functional analysis of erm and some of its enhancers. We generated a new erm mutant allele by gene targeting and reintegrated Gal4 to make an erm enhancer trap strain that could also be used on an erm mutant background. The deletion of three of the previously analysed enhancers showing the most prominent expression patterns of erm by gene targeting resulted in specific temporal and spatial defects in defined brain structures. These defects were already known but here could be assigned to specific enhancer regions. CONCLUSION This analysis is to our knowledge the first systematic analysis of several large enhancer deletions of a Drosophila gene by gene targeting and will enable deeper analysis of erm enhancer functions in the future.
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Affiliation(s)
- Kirsten Hildebrandt
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
| | - Sabrina Kübel
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
- Present address: Clinical and Molecular Virology, Friedrich-Alexander University, 91054, Erlangen, Germany
| | - Marie Minet
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
- Present address: Human Genetics, Saarland University, Building 60, 66421, Homburg/Saar, Germany
| | - Nora Fürst
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
- Present address: Genetics/Epigenetics, Saarland University, Building A2.4, 66123, Saarbrücken, Germany
| | - Christine Klöppel
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
| | - Eva Steinmetz
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany
- Present address: Zoology and Physiology, Saarland University, Building B2.1, 66123, Saarbrücken, Germany
| | - Uwe Walldorf
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Germany.
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7
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Dapergola E, Menegazzi P, Raabe T, Hovhanyan A. Light Stimuli and Circadian Clock Affect Neural Development in Drosophila melanogaster. Front Cell Dev Biol 2021; 9:595754. [PMID: 33763414 PMCID: PMC7982892 DOI: 10.3389/fcell.2021.595754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/02/2021] [Indexed: 11/13/2022] Open
Abstract
Endogenous clocks enable organisms to adapt cellular processes, physiology, and behavior to daily variation in environmental conditions. Metabolic processes in cyanobacteria to humans are under the influence of the circadian clock, and dysregulation of the circadian clock causes metabolic disorders. In mouse and Drosophila, the circadian clock influences translation of factors involved in ribosome biogenesis and synchronizes protein synthesis. Notably, nutrition signals are mediated by the insulin receptor/target of rapamycin (InR/TOR) pathways to regulate cellular metabolism and growth. However, the role of the circadian clock in Drosophila brain development and the potential impact of clock impairment on neural circuit formation and function is less understood. Here we demonstrate that changes in light stimuli or disruption of the molecular circadian clock cause a defect in neural stem cell growth and proliferation. Moreover, we show that disturbed cell growth and proliferation are accompanied by reduced nucleolar size indicative of impaired ribosomal biogenesis. Further, we define that light and clock independently affect the InR/TOR growth regulatory pathway due to the effect on regulators of protein biosynthesis. Altogether, these data suggest that alterations in InR/TOR signaling induced by changes in light conditions or disruption of the molecular clock have an impact on growth and proliferation properties of neural stem cells in the developing Drosophila brain.
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Affiliation(s)
- Eleni Dapergola
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Pamela Menegazzi
- Neurobiology and Genetics, Theodor-Boveri Institute, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Thomas Raabe
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Anna Hovhanyan
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
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8
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Kolb D, Kaspar P, Klöppel C, Walldorf U. The Drosophila homeodomain transcription factor Homeobrain is involved in the formation of the embryonic protocerebrum and the supraesophageal brain commissure. Cells Dev 2021; 165:203657. [PMID: 33993980 DOI: 10.1016/j.cdev.2021.203657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/06/2020] [Accepted: 12/09/2020] [Indexed: 11/28/2022]
Abstract
During the embryonic development of Drosophila melanogaster many transcriptional activators are involved in the formation of the embryonic brain. In our study we show that the transcription factor Homeobrain (Hbn), a member of the 57B homeobox gene cluster, is an additional factor involved in the formation of the embryonic Drosophila brain. Using a Hbn antibody and specific cell type markers a detailed expression analysis during embryonic brain development was conducted. We show that Hbn is expressed in several regions in the protocerebrum, including fibre tract founder cells closely associated with the supraesophageal brain commissure and also in the mushroom bodies. During the formation of the supraesophageal commissure, Hbn and FasII-positive founder cells build an interhemispheric bridge priming the commissure and thereby linking both brain hemispheres. The Hbn expression is restricted to neural but not glial cells in the embryonic brain. In a mutagenesis screen we generated two mutant hbn alleles that both show embryonic lethality. The phenotype of the hbn mutant alleles is characterized by a reduction of the protocerebrum, a loss of the supraesophageal commissure and mushroom body progenitors and also by a dislocation of the optic lobes. Extensive apoptosis correlates with the impaired formation of the embryonic protocerebrum and the supraesophageal commissure. Our results show that Hbn is another important factor for embryonic brain development in Drosophila melanogaster.
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Affiliation(s)
- Dieter Kolb
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Petra Kaspar
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Christine Klöppel
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany
| | - Uwe Walldorf
- Developmental Biology, Saarland University, Building 61, 66421 Homburg/Saar, Germany.
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9
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Rossi AM, Desplan C. Extrinsic activin signaling cooperates with an intrinsic temporal program to increase mushroom body neuronal diversity. eLife 2020; 9:58880. [PMID: 32628110 PMCID: PMC7365662 DOI: 10.7554/elife.58880] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/03/2020] [Indexed: 12/16/2022] Open
Abstract
Temporal patterning of neural progenitors leads to the sequential production of diverse neurons. To understand how extrinsic cues influence intrinsic temporal programs, we studied Drosophila mushroom body progenitors (neuroblasts) that sequentially produce only three neuronal types: γ, then α’β’, followed by αβ. Opposing gradients of two RNA-binding proteins Imp and Syp comprise the intrinsic temporal program. Extrinsic activin signaling regulates the production of α’β’ neurons but whether it affects the intrinsic temporal program was not known. We show that the activin ligand Myoglianin from glia regulates the temporal factor Imp in mushroom body neuroblasts. Neuroblasts missing the activin receptor Baboon have a delayed intrinsic program as Imp is higher than normal during the α’β’ temporal window, causing the loss of α’β’ neurons, a decrease in αβ neurons, and a likely increase in γ neurons, without affecting the overall number of neurons produced. Our results illustrate that an extrinsic cue modifies an intrinsic temporal program to increase neuronal diversity.
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Affiliation(s)
- Anthony M Rossi
- Department of Biology, New York University, New York, United States
| | - Claude Desplan
- Department of Biology, New York University, New York, United States
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10
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Marchetti G, Tavosanis G. Modulators of hormonal response regulate temporal fate specification in the Drosophila brain. PLoS Genet 2019; 15:e1008491. [PMID: 31809495 PMCID: PMC6919624 DOI: 10.1371/journal.pgen.1008491] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 12/18/2019] [Accepted: 10/24/2019] [Indexed: 12/03/2022] Open
Abstract
Neuronal diversity is at the core of the complex processing operated by the nervous system supporting fundamental functions such as sensory perception, motor control or memory formation. A small number of progenitors guarantee the production of this neuronal diversity, with each progenitor giving origin to different neuronal types over time. How a progenitor sequentially produces neurons of different fates and the impact of extrinsic signals conveying information about developmental progress or environmental conditions on this process represent key, but elusive questions. Each of the four progenitors of the Drosophila mushroom body (MB) sequentially gives rise to the MB neuron subtypes. The temporal fate determination pattern of MB neurons can be influenced by extrinsic cues, conveyed by the steroid hormone ecdysone. Here, we show that the activation of Transforming Growth Factor-β (TGF-β) signalling via glial-derived Myoglianin regulates the fate transition between the early-born α’β’ and the pioneer αβ MB neurons by promoting the expression of the ecdysone receptor B1 isoform (EcR-B1). While TGF-β signalling is required in MB neuronal progenitors to promote the expression of EcR-B1, ecdysone signalling acts postmitotically to consolidate theα’β’ MB fate. Indeed, we propose that if these signalling cascades are impaired α’β’ neurons lose their fate and convert to pioneer αβ. Conversely, an intrinsic signal conducted by the zinc finger transcription factor Krüppel-homolog 1 (Kr-h1) antagonises TGF-β signalling and acts as negative regulator of the response mediated by ecdysone in promoting α’β’ MB neuron fate consolidation. Taken together, the consolidation of α’β’ MB neuron fate requires the response of progenitors to local signalling to enable postmitotic neurons to sense a systemic signal. Throughout the development of the central nervous system (CNS), a vast number of neuronal types are produced with striking precision. The unique identity of each neuronal cell type and the great cellular complexity in the CNS are established by intricate gene regulatory networks. Disruption of these identity programs leads to neurodevelopmental disorders and defects in cognition. Here, we report an important regulatory mechanism involved in consolidating neuronal fate. We show that during brain development local signalling, derived from interactions between glial cells and neuronal progenitors, is required to promote the expression of a hormone receptor in immature neurons. The perception of a systemic hormonal cue in those postmitotic neurons is fundamental for the consolidation of their neuronal fate. In this context, we additionally uncover an intrinsic regulatory mechanism that coordinates the hormone response to maintain the final neuronal fate.
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Affiliation(s)
- Giovanni Marchetti
- Dynamics of neuronal circuits, German Center for Neurodegenerative Diseases (DZNE), Germany
- * E-mail: (GM); (GT)
| | - Gaia Tavosanis
- Dynamics of neuronal circuits, German Center for Neurodegenerative Diseases (DZNE), Germany
- LIMES-Institute, University of Bonn, Germany
- * E-mail: (GM); (GT)
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11
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He B, Buescher M, Farnworth MS, Strobl F, Stelzer EHK, Koniszewski NDB, Muehlen D, Bucher G. An ancestral apical brain region contributes to the central complex under the control of foxQ2 in the beetle Tribolium. eLife 2019; 8:e49065. [PMID: 31625505 PMCID: PMC6837843 DOI: 10.7554/elife.49065] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 10/17/2019] [Indexed: 12/11/2022] Open
Abstract
The genetic control of anterior brain development is highly conserved throughout animals. For instance, a conserved anterior gene regulatory network specifies the ancestral neuroendocrine center of animals and the apical organ of marine organisms. However, its contribution to the brain in non-marine animals has remained elusive. Here, we study the function of the Tc-foxQ2 forkhead transcription factor, a key regulator of the anterior gene regulatory network of insects. We characterized four distinct types of Tc-foxQ2 positive neural progenitor cells based on differential co-expression with Tc-six3/optix, Tc-six4, Tc-chx/vsx, Tc-nkx2.1/scro, Tc-ey, Tc-rx and Tc-fez1. An enhancer trap line built by genome editing marked Tc-foxQ2 positive neurons, which projected through the primary brain commissure and later through a subset of commissural fascicles. Eventually, they contributed to the central complex. Strikingly, in Tc-foxQ2 RNAi knock-down embryos the primary brain commissure did not split and subsequent development of midline brain structures stalled. Our work establishes foxQ2 as a key regulator of brain midline structures, which distinguish the protocerebrum from segmental ganglia. Unexpectedly, our data suggest that the central complex evolved by integrating neural cells from an ancestral anterior neuroendocrine center.
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Affiliation(s)
- Bicheng He
- Johann Friedrich Blumenbach Institute of Zoology, GZMBUniversity of GöttingenGöttingenGermany
| | - Marita Buescher
- Johann Friedrich Blumenbach Institute of Zoology, GZMBUniversity of GöttingenGöttingenGermany
| | - Max Stephen Farnworth
- Johann Friedrich Blumenbach Institute of Zoology, GZMBUniversity of GöttingenGöttingenGermany
- Göttingen Graduate Center for Molecular BiosciencesNeurosciences and BiophysicsGöttingenGermany
| | - Frederic Strobl
- Buchmann Institute for Molecular Life Sciences (BMLS)Goethe UniversityFrankfurtGermany
| | - Ernst HK Stelzer
- Buchmann Institute for Molecular Life Sciences (BMLS)Goethe UniversityFrankfurtGermany
| | - Nikolaus DB Koniszewski
- Johann Friedrich Blumenbach Institute of Zoology, GZMBUniversity of GöttingenGöttingenGermany
| | - Dominik Muehlen
- Johann Friedrich Blumenbach Institute of Zoology, GZMBUniversity of GöttingenGöttingenGermany
| | - Gregor Bucher
- Johann Friedrich Blumenbach Institute of Zoology, GZMBUniversity of GöttingenGöttingenGermany
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12
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Curt JR, Yaghmaeian Salmani B, Thor S. Anterior CNS expansion driven by brain transcription factors. eLife 2019; 8:45274. [PMID: 31271353 PMCID: PMC6634974 DOI: 10.7554/elife.45274] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 07/03/2019] [Indexed: 02/06/2023] Open
Abstract
During CNS development, there is prominent expansion of the anterior region, the brain. In Drosophila, anterior CNS expansion emerges from three rostral features: (1) increased progenitor cell generation, (2) extended progenitor cell proliferation, (3) more proliferative daughters. We find that tailless (mouse Nr2E1/Tlx), otp/Rx/hbn (Otp/Arx/Rax) and Doc1/2/3 (Tbx2/3/6) are important for brain progenitor generation. These genes, and earmuff (FezF1/2), are also important for subsequent progenitor and/or daughter cell proliferation in the brain. Brain TF co-misexpression can drive brain-profile proliferation in the nerve cord, and can reprogram developing wing discs into brain neural progenitors. Brain TF expression is promoted by the PRC2 complex, acting to keep the brain free of anti-proliferative and repressive action of Hox homeotic genes. Hence, anterior expansion of the Drosophila CNS is mediated by brain TF driven ‘super-generation’ of progenitors, as well as ‘hyper-proliferation’ of progenitor and daughter cells, promoted by PRC2-mediated repression of Hox activity.
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Affiliation(s)
- Jesús Rodriguez Curt
- Department of Clinical and Experimental Medicine, Linkoping University, Linkoping, Sweden
| | | | - Stefan Thor
- Department of Clinical and Experimental Medicine, Linkoping University, Linkoping, Sweden.,School of Biomedical Sciences, University of Queensland, Saint Lucia, Australia
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13
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Yang CP, Samuels TJ, Huang Y, Yang L, Ish-Horowicz D, Davis I, Lee T. Imp and Syp RNA-binding proteins govern decommissioning of Drosophila neural stem cells. Development 2017; 144:3454-3464. [PMID: 28851709 PMCID: PMC5665480 DOI: 10.1242/dev.149500] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 08/21/2017] [Indexed: 02/03/2023]
Abstract
The termination of the proliferation of Drosophila neural stem cells, also known as neuroblasts (NBs), requires a ‘decommissioning’ phase that is controlled in a lineage-specific manner. Most NBs, with the exception of those of the mushroom body (MB), are decommissioned by the ecdysone receptor and mediator complex, causing them to shrink during metamorphosis, followed by nuclear accumulation of Prospero and cell cycle exit. Here, we demonstrate that the levels of Imp and Syp RNA-binding proteins regulate NB decommissioning. Descending Imp and ascending Syp expression have been shown to regulate neuronal temporal fate. We show that Imp levels decline slower in the MB than in other central brain NBs. MB NBs continue to express Imp into pupation, and the presence of Imp prevents decommissioning partly by inhibiting the mediator complex. Late-larval induction of transgenic Imp prevents many non-MB NBs from decommissioning in early pupae. Moreover, the presence of abundant Syp in aged NBs permits Prospero accumulation that, in turn, promotes cell cycle exit. Together, our results reveal that progeny temporal fate and progenitor decommissioning are co-regulated in protracted neuronal lineages. Highlighted Article: Temporal progression of Imp/Syp gradients determines the timing of neuroblast decommissioning and cell cycle exit in addition to progeny temporal fate, allowing proper completion of a neuronal lineage.
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Affiliation(s)
- Ching-Po Yang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Tamsin J Samuels
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Yaling Huang
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Lu Yang
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.,MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Tzumin Lee
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
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14
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Orquera DP, de Souza FSJ. Evolution of the Rax family of developmental transcription factors in vertebrates. Mech Dev 2016; 144:163-170. [PMID: 27838261 DOI: 10.1016/j.mod.2016.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 11/01/2016] [Accepted: 11/07/2016] [Indexed: 02/09/2023]
Abstract
Rax proteins comprise a small family of paired-type, homeodomain-containing transcription factors with essential functions in eye and forebrain development. While invertebrates possess only one Rax gene, vertebrates can have several Rax paralogue genes, but the evolutionary history of the members of the family has not been studied in detail. Here, we present a thorough analysis of the evolutionary relationships between vertebrate Rax genes and proteins available in diverse genomic databases. Phylogenetic and synteny analyses indicate that Rax genes went through a duplication in an ancestor of all jawed vertebrates (Gnathostomata), giving rise to the ancestral vertebrate Rax1 and Rax2 genes. This duplication event is likely related to the proposed polyploidisations that occurred during early vertebrate evolution. Subsequent genome-wide duplications in the lineage of ray-finned fish (Actinopterygii) originated new Rax2 paralogues in the genomes of teleosts. In the lobe-finned fish lineage (Sarcopterygii), the N-terminal octapeptide domain of Rax2 was lost in a common ancestor of tetrapods, giving rise to a shorter version of Rax2 in this lineage. Within placental mammals, the Rax2 gene was lost altogether in an ancestor of rodents and lagomorphs (Glires). Finally, we discuss the scientific literature in the light of Rax gene evolution and propose new avenues of research on the function of this important family of transcriptional regulators.
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Affiliation(s)
- Daniela P Orquera
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina
| | - Flávio S J de Souza
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina.
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