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Kloc M, Tworzydło W, Szklarzewicz T. Germline and Somatic Cell Syncytia in Insects. Results Probl Cell Differ 2024; 71:47-63. [PMID: 37996672 DOI: 10.1007/978-3-031-37936-9_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
Syncytia are common in the animal and plant kingdoms both under normal and pathological conditions. They form through cell fusion or division of a founder cell without cytokinesis. A particular type of syncytia occurs in invertebrate and vertebrate gametogenesis when the founder cell divides several times with partial cytokinesis producing a cyst (nest) of germ line cells connected by cytoplasmic bridges. The ultimate destiny of the cyst's cells differs between animal groups. Either all cells of the cyst become the gametes or some cells endoreplicate or polyploidize to become the nurse cells (trophocytes). Although many types of syncytia are permanent, the germ cell syncytium is temporary, and eventually, it separates into individual gametes. In this chapter, we give an overview of syncytium types and focus on the germline and somatic cell syncytia in various groups of insects. We also describe the multinuclear giant cells, which form through repetitive nuclear divisions and cytoplasm hypertrophy, but without cell fusion, and the accessory nuclei, which bud off the oocyte nucleus, migrate to its cortex and become included in the early embryonic syncytium.
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Affiliation(s)
- Malgorzata Kloc
- The Houston Methodist Research Institute, Houston, TX, USA.
- The Houston Methodist Hospital, Department of Surgery, Houston, TX, USA.
- Department of Genetics, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA.
| | - Wacław Tworzydło
- Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
| | - Teresa Szklarzewicz
- Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
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Lowe DD, Montell DJ. Unconventional translation initiation factor EIF2A is required for Drosophila spermatogenesis. Dev Dyn 2022; 251:377-389. [PMID: 34278643 PMCID: PMC10885012 DOI: 10.1002/dvdy.403] [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: 04/17/2021] [Revised: 06/23/2021] [Accepted: 07/09/2021] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND EIF2A is an unconventional translation factor required for initiation of protein synthesis from non-AUG codons from a variety of transcripts, including oncogenes and stress related transcripts in mammalian cells. Its function in multicellular organisms has not been reported. RESULTS Here, we identify and characterize mutant alleles of the CG7414 gene, which encodes the Drosophila EIF2A ortholog. We identified that CG7414 undergoes sex-specific splicing that regulates its male-specific expression. We characterized a Mi{Mic} transposon insertion that disrupts the coding regions of all predicted isoforms and is a likely null allele, and a PBac transposon insertion into an intron, which is a hypomorph. The Mi{Mic} allele is homozygous lethal, while the viable progeny from the hypomorphic PiggyBac allele are male sterile and female fertile. In dEIF2A mutant flies, sperm failed to individualize due to defects in F-actin cones and failure to form and maintain cystic bulges, ultimately leading to sterility. CONCLUSIONS These results demonstrate that EIF2A is essential in a multicellular organism, both for normal development and spermatogenesis, and provide an entrée into the elucidation of the role of EIF2A and unconventional translation in vivo.
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Affiliation(s)
- David D Lowe
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, USA
| | - Denise J Montell
- Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, USA
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Banho CA, Mérel V, Oliveira TYK, Carareto CMA, Vieira C. Comparative transcriptomics between Drosophila mojavensis and D. arizonae reveals transgressive gene expression and underexpression of spermatogenesis-related genes in hybrid testes. Sci Rep 2021; 11:9844. [PMID: 33972659 PMCID: PMC8110761 DOI: 10.1038/s41598-021-89366-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/19/2021] [Indexed: 01/02/2023] Open
Abstract
Interspecific hybridization is a stressful condition that can lead to sterility and/or inviability through improper gene regulation in Drosophila species with a high divergence time. However, the extent of these abnormalities in hybrids of recently diverging species is not well known. Some studies have shown that in Drosophila, the mechanisms of postzygotic isolation may evolve more rapidly in males than in females and that the degree of viability and sterility is associated with the genetic distance between species. Here, we used transcriptomic comparisons between two Drosophila mojavensis subspecies and D. arizonae (repleta group, Drosophila) and identified greater differential gene expression in testes than in ovaries. We tested the hypothesis that the severity of the interspecies hybrid phenotype is associated with the degree of gene misregulation. We showed limited gene misregulation in fertile females and an increase in the amount of misregulation in males with more severe sterile phenotypes (motile vs. amotile sperm). In addition, for these hybrids, we identified candidate genes that were mostly associated with spermatogenesis dysfunction.
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Affiliation(s)
- Cecilia A Banho
- Department of Biology, UNESP - São Paulo State University, São José do Rio Preto, São Paulo State (SP), Brazil.,Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Claude Bernard Lyon 1, University of Lyon, 69622, Villeurbanne, France
| | - Vincent Mérel
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Claude Bernard Lyon 1, University of Lyon, 69622, Villeurbanne, France
| | - Thiago Y K Oliveira
- Laboratory of Molecular Immunology, The Rockefeller University, New York, NY, USA
| | - Claudia M A Carareto
- Department of Biology, UNESP - São Paulo State University, São José do Rio Preto, São Paulo State (SP), Brazil
| | - Cristina Vieira
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Claude Bernard Lyon 1, University of Lyon, 69622, Villeurbanne, France.
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Fabrizio JJ, Rollins J, Bazinet CW, Wegener S, Koziy I, Daniel R, Lombardo V, Pryce D, Bharrat K, Innabi E, Villanobos M, Mendoza G, Ferrara E, Rodway S, Vicioso M, Siracusa V, Dailey E, Pronovost J, Innabi S, Patel V, DeSouza N, Quaranto D, Niknejad A. Tubulin-binding cofactor E-like (TBCEL), the protein product of the mulet gene, is required in the germline for the regulation of inter-flagellar microtubule dynamics during spermatid individualization. Biol Open 2020; 9:bio049080. [PMID: 32033965 PMCID: PMC7055396 DOI: 10.1242/bio.049080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/22/2020] [Indexed: 11/14/2022] Open
Abstract
Individual sperm cells are resolved from a syncytium during late step of spermiogenesis known as individualization, which is accomplished by an Individualization Complex (IC) composed of 64 investment cones. mulet encodes Tubulin-binding cofactor E-like (TBCEL), suggesting a role for microtubule dynamics in individualization. Indeed, a population of ∼100 cytoplasmic microtubules fails to disappear in mulet mutant testes during spermatogenesis. This persistence, detected using epi-fluorescence and electron microscopy, suggests that removal of these microtubules by TBCEL is a prerequisite for individualization. Immunofluorescence reveals TBCEL expression in elongated spermatid cysts. In addition, testes from mulet mutant males were rescued to wild type using tubulin-Gal4 to drive TBCEL expression, indicating that the mutant phenotype is caused by the lack of TBCEL. Finally, RNAi driven by bam-GAL4 successfully phenocopied mulet, confirming that mulet is required in the germline for individualization. We propose a model in which the cytoplasmic microtubules serve as alternate tracks for investment cones in mulet mutant testes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- James J Fabrizio
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Janet Rollins
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | | | - Stephanie Wegener
- Leibniz Institute for Neurobiology Magdeburg, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Iryna Koziy
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Rachel Daniel
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Vincent Lombardo
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Dwaine Pryce
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Kavita Bharrat
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Elissa Innabi
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Marielle Villanobos
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Gabriela Mendoza
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Elisa Ferrara
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Stephanie Rodway
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Matthew Vicioso
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Victoria Siracusa
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Erin Dailey
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Justin Pronovost
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Simon Innabi
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Vrutant Patel
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Nicole DeSouza
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Danielle Quaranto
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Amir Niknejad
- Department of Mathematics, College of Mt St Vincent, Bronx, NY 10471, USA
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