1
|
Ramos I, Machado E, Masuda H, Gomes F. Open questions on the functional biology of the yolk granules during embryo development. Mol Reprod Dev 2022; 89:86-94. [PMID: 35020238 DOI: 10.1002/mrd.23555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/28/2021] [Accepted: 01/03/2022] [Indexed: 12/21/2022]
Abstract
Biogenesis and consumption of the yolk are well-conserved aspects of the reproductive biology in oviparous species. Most egg-laying animals accumulate yolk proteins within the oocytes thus creating the source of nutrients and energy that will feed embryo development. Yolk accumulation drives the generation of a highly specialized oocyte cytoplasm with maternal mRNAs, ribosomes, mitochondria, and, mainly, a set of organelles collectively referred to as yolk granules (Ygs). Following fertilization, the Ygs are involved in regulated mechanisms of yolk degradation to fuel the anabolic metabolism of the growing embryo. Thus, yolk accumulation and degradation are essential processes that allow successful development in many species. Nevertheless, the molecular machinery and mechanisms dedicated to the programmed yolk mobilization throughout development are still enigmatic and remain mostly unexplored. Moreover, while the Ygs functional biology as a nutritional source for the embryo has been acknowledged, several reports have suggested that Ygs cargoes and functions go far beyond yolk storage. Evidence of the role of Ygs in gene expression, microbiota harboring, and paracrine signaling has been proposed. In this study, we summarize the current knowledge of the Ygs functional biology pointing to open questions and where further investigation is needed.
Collapse
Affiliation(s)
- Isabela Ramos
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular - INCT-EM/CNPq, Rio de Janeiro, Brazil
| | - Ednildo Machado
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular - INCT-EM/CNPq, Rio de Janeiro, Brazil.,Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Hatisaburo Masuda
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular - INCT-EM/CNPq, Rio de Janeiro, Brazil
| | - Fabio Gomes
- Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| |
Collapse
|
2
|
Vieira PH, Benjamim CF, Atella G, Ramos I. VPS38/UVRAG and ATG14, the variant regulatory subunits of the ATG6/Beclin1-PI3K complexes, are crucial for the biogenesis of the yolk organelles and are transcriptionally regulated in the oocytes of the vector Rhodnius prolixus. PLoS Negl Trop Dis 2021; 15:e0009760. [PMID: 34492013 PMCID: PMC8448300 DOI: 10.1371/journal.pntd.0009760] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/17/2021] [Accepted: 08/24/2021] [Indexed: 02/07/2023] Open
Abstract
In insects the reserve proteins are stored in the oocytes into endocytic-originated vesicles named yolk organelles. VPS38/UVRAG and ATG14 are the variant regulatory subunits of two class-III ATG6/Beclin1 PI3K complexes that regulate the recruitment of the endocytic (complex II) and autophagic (complex I) machineries. In a previous work from our group, we found that the silencing of ATG6/Beclin1 resulted in the formation of yolk-deficient oocytes due to defects in the endocytosis of the yolk proteins. Because ATG6/Beclin1 is present in the two above-described PI3K complexes, we could not identify the contributions of each complex to the yolk defective phenotypes. To address this, here we investigated the role of the variant subunits VPS38/UVRAG (complex II, endocytosis) and ATG14 (complex I, autophagy) in the biogenesis of the yolk organelles in the insect vector of Chagas Disease Rhodnius prolixus. Interestingly, the silencing of both genes phenocopied the silencing of ATG6/Beclin1, generating 1) accumulation of yolk proteins in the hemolymph; 2) white, smaller, and yolk-deficient oocytes; 3) abnormal yolk organelles in the oocyte cortex; and 4) unviable F1 embryos. However, we found that the similar phenotypes were the result of a specific cross-silencing effect among the PI3K subunits where the silencing of VPS38/UVRAG and ATG6/Beclin1 resulted in the specific silencing of each other, whereas the silencing of ATG14 triggered the silencing of all three PI3K components. Because the silencing of VPS38/UVRAG and ATG6/Beclin1 reproduced the yolk-deficiency phenotypes without the cross silencing of ATG14, we concluded that the VPS38/UVRAG PI3K complex II was the major contributor to the previously observed phenotypes in silenced insects. Altogether, we found that class-III ATG6/Beclin1 PI3K complex II (VPS38/UVRAG) is essential for the yolk endocytosis and that the subunits of both complexes are under an unknown transcriptional regulatory system.
Collapse
Affiliation(s)
- Priscila H Vieira
- Laboratório de Bioquímica de Insetos, Instituto de Bioquímica Médica Leopoldo de Meis. Universidade Federal do Rio de Janeiro, Brazil
| | - Claudia F Benjamim
- Laboratório de Imunologia Molecular e Celular, Instituto de Biofísica Carlos Chagas Filho (IBCCF), Universidade Federal do Rio de Janeiro, Brazil
| | - Georgia Atella
- Laboratório de de Bioquímica de Lipídeos e Lipoproteínas, Instituto de Bioquímica Médica Leopoldo de Meis. Universidade Federal do Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular-INCT-EM/CNPq. Rio de Janeiro, Brazil
| | - Isabela Ramos
- Laboratório de Bioquímica de Insetos, Instituto de Bioquímica Médica Leopoldo de Meis. Universidade Federal do Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular-INCT-EM/CNPq. Rio de Janeiro, Brazil
| |
Collapse
|
3
|
Doğan C, Hänniger S, Heckel DG, Coutu C, Hegedus DD, Crubaugh L, Groves RL, Mutlu DA, Suludere Z, Bayram Ş, Toprak U. Characterization of calcium signaling proteins from the fat body of the Colorado Potato Beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae): Implications for diapause and lipid metabolism. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 133:103549. [PMID: 33610660 DOI: 10.1016/j.ibmb.2021.103549] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/26/2021] [Accepted: 01/31/2021] [Indexed: 05/25/2023]
Abstract
Calcium (Ca2+) regulates many cellular and physiological processes from development to reproduction. Ca2+ is also an important factor in the metabolism of lipids, the primary energy source used during insect starvation and diapause. Ca2+ signaling proteins bind to Ca2+ and maintain intracellular Ca2+ levels. However, knowledge about Ca2+ signaling proteins is mostly restricted to the model Drosophila melanogaster and the response of Ca2+ signaling genes to starvation or diapause is not known. In this study, we identified three Ca2+ signaling proteins; the primary Ca2+ binding protein Calmodulin (LdCaM), phosphatase Calcineurin B (LdCaNB), and the senescence marker protein Regucalcin (LdRgN), from the fat body of the Colorado Potato Beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae). This insect is a major pest of potato worldwide and overwinters under hibernation diapause as adults while utilizing lipids as the primary energy source. Putative EF-hand domains involved in Ca2+ binding were present in LdCaM, LdCaNB, but absent in LdRgN. LdCaM and LdCaNB were expressed in multiple tissues, while LdRgN was primarily expressed in the fat body. LdCaM was constitutively-expressed throughout larval development and at the adult stage. LdCaNB was primarily expressed in feeding larvae, and LdRgN in both feeding larvae and adults at comparable levels; however, both genes were down-regulated by molting. A response to starvation was observed only for LdRgN. Transcript abundance analysis in the entire body in relation to diapause revealed differential regulation with a general suppression during diapause, and higher mRNA levels in favor of females at post-diapause for LdCaM, and in favor of males at non-diapause for LdCaNB. Fat body-specific transcript abundance was not different between non-diapause and post-diapause for LdCaNB, but both LdCaM and LdRgN were down-regulated in males and both sexes, respectively by post-diapause. Silencing LdCaNB or LdRgN in larvae led to decreased fat content, indicating their involvement in lipid accumulation, while RNAi of LdCaM led to lethality.
Collapse
Affiliation(s)
- Cansu Doğan
- Ankara University, Molecular Entomology Lab., Dept. of Plant Protection, Faculty of Agriculture, Ankara, Turkey; Max Planck Institute for Chemical Ecology, Dept. of Entomology, Jena, Germany; Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, SK, Canada; Dept. of Entomology, University of Wisconsin-Madison, Madison, WI, USA
| | - Sabine Hänniger
- Max Planck Institute for Chemical Ecology, Dept. of Entomology, Jena, Germany
| | - David G Heckel
- Max Planck Institute for Chemical Ecology, Dept. of Entomology, Jena, Germany
| | - Cathy Coutu
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, SK, Canada
| | - Dwayne D Hegedus
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, SK, Canada
| | - Linda Crubaugh
- Dept. of Entomology, University of Wisconsin-Madison, Madison, WI, USA
| | - Russell L Groves
- Dept. of Entomology, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Zekiye Suludere
- Gazi University, Faculty of Sciences, Department of Biology, Ankara, Turkey
| | - Şerife Bayram
- Ankara University, Molecular Entomology Lab., Dept. of Plant Protection, Faculty of Agriculture, Ankara, Turkey
| | - Umut Toprak
- Ankara University, Molecular Entomology Lab., Dept. of Plant Protection, Faculty of Agriculture, Ankara, Turkey.
| |
Collapse
|
4
|
Gaps and barriers: Gap junctions as a channel of communication between the soma and the germline. Semin Cell Dev Biol 2019; 97:167-171. [PMID: 31558347 DOI: 10.1016/j.semcdb.2019.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 08/29/2019] [Accepted: 09/04/2019] [Indexed: 12/20/2022]
Abstract
Gap junctions, expressed in most tissues of the body, allow for the cytoplasmic coupling of adjacent cells and promote tissue cooperation. Gap junctions connect also the soma and the germline in many animals, and transmit somatic signals that are crucial for germline maturation and integrity. In this review, we examine the involvement of gap junctions in the relay of information between the soma and the germline, and ask whether such communication could have consequences for the progeny. While the influence of parental experiences on descendants is of great interest, the possibility that gap junctions participate in the transmission of information across generations is largely unexplored.
Collapse
|
5
|
Sánchez A, Castro C, Flores DL, Gutiérrez E, Baldi P. Gap Junction Channels of Innexins and Connexins: Relations and Computational Perspectives. Int J Mol Sci 2019; 20:E2476. [PMID: 31109150 PMCID: PMC6566657 DOI: 10.3390/ijms20102476] [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: 03/30/2019] [Revised: 05/04/2019] [Accepted: 05/14/2019] [Indexed: 12/16/2022] Open
Abstract
Gap junction (GJ) channels in invertebrates have been used to understand cell-to-cell communication in vertebrates. GJs are a common form of intercellular communication channels which connect the cytoplasm of adjacent cells. Dysregulation and structural alteration of the gap junction-mediated communication have been proven to be associated with a myriad of symptoms and tissue-specific pathologies. Animal models relying on the invertebrate nervous system have exposed a relationship between GJs and the formation of electrical synapses during embryogenesis and adulthood. The modulation of GJs as a therapeutic and clinical tool may eventually provide an alternative for treating tissue formation-related diseases and cell propagation. This review concerns the similarities between Hirudo medicinalis innexins and human connexins from nucleotide and protein sequence level perspectives. It also sets forth evidence of computational techniques applied to the study of proteins, sequences, and molecular dynamics. Furthermore, we propose machine learning techniques as a method that could be used to study protein structure, gap junction inhibition, metabolism, and drug development.
Collapse
Affiliation(s)
- Alejandro Sánchez
- Facultad de Ciencias, Universidad Autónoma de Baja California, Ensenada, Baja California 22860, Mexico.
| | - Carlos Castro
- Facultad of Ingeniería, Arquitectura y Diseño, Universidad Autónoma de Baja California, Ensenada, Baja California 22860, Mexico.
| | - Dora-Luz Flores
- Facultad of Ingeniería, Arquitectura y Diseño, Universidad Autónoma de Baja California, Ensenada, Baja California 22860, Mexico.
| | - Everardo Gutiérrez
- Facultad de Ciencias, Universidad Autónoma de Baja California, Ensenada, Baja California 22860, Mexico.
| | - Pierre Baldi
- Department of Computer Science, Institute for Genomics and Bioinformatics, and Center for Machine Learning and Intelligent Systems, University of California, Irvine, CA 92697, USA.
| |
Collapse
|
6
|
Wang W, Wan P, Lai F, Zhu T, Fu Q. Double-stranded RNA targeting calmodulin reveals a potential target for pest management of Nilaparvata lugens. PEST MANAGEMENT SCIENCE 2018; 74:1711-1719. [PMID: 29381254 DOI: 10.1002/ps.4865] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 01/03/2018] [Accepted: 01/11/2018] [Indexed: 06/07/2023]
Abstract
BACKGROUND Calmodulin (CaM) is an essential protein in cellular activity and plays important roles in many processes in insect development. RNA interference (RNAi) has been hypothesized to be a promising method for pest control. CaM is a good candidate for RNAi target. However, the sequence and function of CaM in Nilaparvata lugens are unknown. Furthermore, the double-stranded RNA (dsRNA) target to CaM gene in pest control is still unavailable. RESULTS In the present study, two alternatively spliced variants of CaM transcripts, designated NlCaM1 and NlCaM2, were cloned from N. lugens. The two cDNA sequences exhibited 100% identity to each other in the open reading frame (ORF), and only differed in the 3' untranslated region (UTR). NlCaM including NlCaM1 and NlCaM2 mRNA was detectable in all developmental stages and tissues of N. lugens, with significantly increased expression in the salivary glands. Knockdown of NlCaM expression by RNAi with different dsRNAs led to an inability to molt properly, increased mortality, which ranged from 49.7 to 92.5%, impacted development of the ovaries and led to female infertility. There were no significant reductions in the transcript levels of vitellogenin and its receptor or in the total vitellogenin protein level relative to the control group. However, a significant reduction in vitellogenin protein was detected in ovaries injected with dsNlCaM. In addition, a specific dsRNA of NlCaM for control of N. lugens was designed and tested. CONCLUSION NlCaM plays important roles mainly in nymph development and uptake of vitellogenin by ovaries in vitellogenesis in N. lugens. dsRNA derived from the less conserved 3'-UTR of NlCaM shows great potential for RNAi-based N. lugens management. © 2018 Society of Chemical Industry.
Collapse
Affiliation(s)
- Weixia Wang
- State Key Lab of Rice Biology, China Rice Research Institute, Hangzhou, Zhejiang, China
| | - Pinjun Wan
- State Key Lab of Rice Biology, China Rice Research Institute, Hangzhou, Zhejiang, China
| | - Fengxiang Lai
- State Key Lab of Rice Biology, China Rice Research Institute, Hangzhou, Zhejiang, China
| | - Tingheng Zhu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, China
| | - Qiang Fu
- State Key Lab of Rice Biology, China Rice Research Institute, Hangzhou, Zhejiang, China
| |
Collapse
|
7
|
Mathews J, Levin M. Gap junctional signaling in pattern regulation: Physiological network connectivity instructs growth and form. Dev Neurobiol 2017; 77:643-673. [PMID: 27265625 PMCID: PMC10478170 DOI: 10.1002/dneu.22405] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 12/19/2022]
Abstract
Gap junctions (GJs) are aqueous channels that allow cells to communicate via physiological signals directly. The role of gap junctional connectivity in determining single-cell functions has long been recognized. However, GJs have another important role: the regulation of large-scale anatomical pattern. GJs are not only versatile computational elements that allow cells to control which small molecule signals they receive and emit, but also establish connectivity patterns within large groups of cells. By dynamically regulating the topology of bioelectric networks in vivo, GJs underlie the ability of many tissues to implement complex morphogenesis. Here, a review of recent data on patterning roles of GJs in growth of the zebrafish fin, the establishment of left-right patterning, the developmental dysregulation known as cancer, and the control of large-scale head-tail polarity, and head shape in planarian regeneration has been reported. A perspective in which GJs are not only molecular features functioning in single cells, but also enable global neural-like dynamics in non-neural somatic tissues has been proposed. This view suggests a rich program of future work which capitalizes on the rapid advances in the biophysics of GJs to exploit GJ-mediated global dynamics for applications in birth defects, regenerative medicine, and morphogenetic bioengineering. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 643-673, 2017.
Collapse
Affiliation(s)
- Juanita Mathews
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, MA
| | - Michael Levin
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, MA
| |
Collapse
|
8
|
Fruttero LL, Leyria J, Canavoso LE. Lipids in Insect Oocytes: From the Storage Pathways to Their Multiple Functions. Results Probl Cell Differ 2017; 63:403-434. [PMID: 28779328 DOI: 10.1007/978-3-319-60855-6_18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In insect physiology, the mechanisms involved in the buildup and regulation of yolk proteins in developing oocytes have been thoroughly researched during the last three decades. Comparatively, the study of lipid metabolism in oocytes had received less attention. The importance of this issue lies in the fact that lipids make up to 40% of the dry weight of an insect egg, being the most important supply of energy for the developing embryo. Since the oocyte has a very limited capacity to synthesize lipids de novo, most of the lipids in the mature eggs arise from the circulation. The main lipid carriers in the insect circulatory system are the lipoproteins lipophorin and vitellogenin. In some species, the endocytosis of lipophorin and vitellogenin may account for about 10% of the lipids present in mature eggs. Thus, most of the lipids are transferred by a lipophorin-mediated pathway, in which the lipoprotein unloads its lipid cargo at the surface of oocytes without internalization. This chapter recapitulates the current status on lipid storage and its utilization in insect oocytes and discusses the participation of key factors including lipoproteins, transfer proteins, lipolytic enzymes, and dynamic organelles such as lipid droplets. The new findings in the field of lipophorin receptors are presented in the context of lipid accumulation during egg maturation, and the roles of lipids beyond energy source are summarized from the perspective of oogenesis and embryogenesis. Finally, prospective and fruitful areas of future research are suggested.
Collapse
Affiliation(s)
- Leonardo L Fruttero
- Instituto do Cerebro (InsCer). Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Jimena Leyria
- Departamento de Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina
| | - Lilián E Canavoso
- Departamento de Bioquímica Clínica, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, CP 5000, Argentina.
| |
Collapse
|
9
|
Furriols M, Casanova J. Germline and somatic vitelline proteins colocalize in aggregates in the follicular epithelium of Drosophila ovaries. Fly (Austin) 2015; 8:113-9. [PMID: 25483249 DOI: 10.4161/fly.29133] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Nasrat and Polehole, two Drosophila proteins related functionally and by sequence, are secreted from the oocyte and incorporated into the vitelline membrane, where they play a role in the integrity of the same and in the activation of embryonic Torso RTK. In addition, they also accumulate in a punctate pattern in the follicular epithelium. Here we show that their accumulation at the follicle cells depends on their gene expression in the germline, indicating that these proteins move from the oocyte to the follicle cells in a process that does not require endocytosis. Finally we used cell markers to examine the distribution of these proteins at the follicle cells and show they accumulated in aggregates with vitelline membrane proteins in close association with the plasmatic membrane. We propose that these aggregates represent spatially restricted sinks for vitelline membrane proteins that fail to be incorporated into vitelline bodies and later on into the vitelline membrane.
Collapse
Affiliation(s)
- Marc Furriols
- a Institut de Biologia Molecular de Barcelona (IBMB-CSIC); Barcelona, Catalonia, Spain
| | | |
Collapse
|
10
|
Chernet BT, Levin M. Transmembrane voltage potential is an essential cellular parameter for the detection and control of tumor development in a Xenopus model. Dis Model Mech 2013; 6:595-607. [PMID: 23471912 PMCID: PMC3634644 DOI: 10.1242/dmm.010835] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Understanding mechanisms that orchestrate cell behavior into appropriately patterned tissues and organs within the organism is an essential element of preventing, detecting and treating cancer. Bioelectric signals (resting transmembrane voltage potential gradients in all cells) underlie an important and broadly conserved set of control mechanisms that regulate pattern formation. We tested the role of transmembrane potential in tumorigenesis mediated by canonical oncogenes in Xenopus laevis. Depolarized membrane potential (Vmem) was a characteristic of induced tumor-like structures (ITLSs) generated by overexpression of Gli1, KrasG12D, Xrel3 or p53Trp248. This bioelectric signature was also present in precursor ITLS sites. Vmem is a bioelectric marker that reveals ITLSs before they become histologically and morphologically apparent. Moreover, voltage was functionally important: overexpression of hyperpolarizing ion transporters caused a return to normal Vmem and significantly reduced ITLS formation in vivo. To characterize the molecular mechanism by which Vmem change regulates ITLS phenotypes, we performed a suppression screen. Vmem hyperpolarization was transduced into downstream events via Vmem-regulated activity of SLC5A8, a sodium-butyrate exchanger previously implicated in human cancer. These data indicate that butyrate, a histone deacetylase (HDAC) inhibitor, might be responsible for transcriptional events that mediate suppression of ITLSs by hyperpolarization. Vmem is a convenient cellular parameter by which tumors induced by human oncogenes can be detected in vivo and represents a new diagnostic modality. Moreover, control of resting membrane potential is functionally involved in the process by which oncogene-bearing cells depart from normal morphogenesis programs to form tumors. Modulation of Vmem levels is a novel and promising strategy for tumor normalization.
Collapse
Affiliation(s)
- Brook T Chernet
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University, 200 Boston Avenue, Medford, MA 02155, USA
| | | |
Collapse
|
11
|
Brubaker-Purkey BJ, Woodruff RI. Vitellogenesis in the fruit fly, Drosophila melanogaster: antagonists demonstrate that the PLC, IP3/DAG, PK-C pathway is triggered by calmodulin. JOURNAL OF INSECT SCIENCE (ONLINE) 2013; 13:68. [PMID: 24228869 PMCID: PMC3835028 DOI: 10.1673/031.013.6801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 07/19/2012] [Indexed: 06/02/2023]
Abstract
In Drosophila melanogaster M. (Diptera: Drosophilidae), a phospholipase-C to proteininase-C signal cascade leads to the endocytic uptake of yolk precursor molecules. The data suggest that D. melanogaster has a phospholipase-C/proteinkinase-C signaling pathway similar to that previously shown to be required for vitellogenesis in the milkweed bug, Oncopeltus fasciatus Dallas (Hemiptera: Lygaeidae). Calmodulin, derived from epithelial cells and transported to the oocytes via gap junctions, may trigger this pathway. To investigate this, a series of known antagonists to various elements of the pathway were used. W-7 (which prevents calmodulin binding to phospholipase-C), U-73122 (which prevents activation of phospholipase-C), verapamil (which blocks Ca(2+) release by IP3), HAG (which blocks diacylglycerol), and staurosporine (which inactivates proteinkinase-C) were each shown to inhibit endocytosis, thereby blocking formation of nascent yolk spheres.
Collapse
|
12
|
Mukai M, Kato H, Hira S, Nakamura K, Kita H, Kobayashi S. Innexin2 gap junctions in somatic support cells are required for cyst formation and for egg chamber formation in Drosophila. Mech Dev 2011; 128:510-23. [PMID: 22001874 DOI: 10.1016/j.mod.2011.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 09/27/2011] [Accepted: 09/29/2011] [Indexed: 01/03/2023]
Abstract
Germ cells require intimate associations with surrounding somatic cells during gametogenesis. During oogenesis, gap junctions mediate communication between germ cells and somatic support cells. However, the molecular mechanisms by which gap junctions regulate the developmental processes during oogenesis are poorly understood. We have identified a female sterile allele of innexin2 (inx2), which encodes a gap junction protein in Drosophila. In females bearing this inx2 allele, cyst formation and egg chamber formation are impaired. In wild-type germaria, Inx2 is strongly expressed in escort cells and follicle cells, both of which make close contact with germline cells. We show that inx2 function in germarial somatic cells is required for the survival of early germ cells and promotes cyst formation, probably downstream of EGFR pathway, and that inx2 function in follicle cells promotes egg chamber formation through the regulation of DE-cadherin and Bazooka (Baz) at the boundary between germ cells and follicle cells. Furthermore, genetic experiments demonstrate that inx2 interacts with the zero population growth (zpg) gene, which encodes a germline-specific gap junction protein. These results indicate a multifunctional role for Inx2 gap junctions in somatic support cells in the regulation of early germ cell survival, cyst formation and egg chamber formation. Inx2 gap junctions may mediate the transfer of nutrients and signal molecules between germ cells and somatic support cells, as well as play a role in the regulation of cell adhesion.
Collapse
Affiliation(s)
- Masanori Mukai
- Department of Biology, Faculty of Science and Engineering, Konan University, Okamoto, Higashinada, Kobe, Japan.
| | | | | | | | | | | |
Collapse
|
13
|
Abstract
The aim of the present study was to show the participation and physiological role of calmodulin (CaM) and cAMP during vitellogenin endocytic uptake in the amphibian Xenopus laevis. The results showed a differential distribution of CaM in the ovary follicles during oogenesis. The CaM intracellular localization was not affected by gap junction's downregulation and CaM inhibition did not completely abolished the endocytic activity of oocytes. We showed that cAMP was able to completely rescue the endocytic competence in follicles in which gap junctional communication had been disrupted by octanol. Moreover cAMP was capable of restoring oocyte endocytic capability in the presence of octanol and stelazine, a CaM inhibitor. We propose that, in Vtg uptake regulation, cAMP is upstream of CaM during the endocytic signalling pathway.
Collapse
|
14
|
Blackiston D, Adams DS, Lemire JM, Lobikin M, Levin M. Transmembrane potential of GlyCl-expressing instructor cells induces a neoplastic-like conversion of melanocytes via a serotonergic pathway. Dis Model Mech 2011; 4:67-85. [PMID: 20959630 PMCID: PMC3008964 DOI: 10.1242/dmm.005561] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 08/23/2010] [Indexed: 12/14/2022] Open
Abstract
Understanding the mechanisms that coordinate stem cell behavior within the host is a high priority for developmental biology, regenerative medicine and oncology. Endogenous ion currents and voltage gradients function alongside biochemical cues during pattern formation and tumor suppression, but it is not known whether bioelectrical signals are involved in the control of stem cell progeny in vivo. We studied Xenopus laevis neural crest, an embryonic stem cell population that gives rise to many cell types, including melanocytes, and contributes to the morphogenesis of the face, heart and other complex structures. To investigate how depolarization of transmembrane potential of cells in the neural crest's environment influences its function in vivo, we manipulated the activity of the native glycine receptor chloride channel (GlyCl). Molecular-genetic depolarization of a sparse, widely distributed set of GlyCl-expressing cells non-cell-autonomously induces a neoplastic-like phenotype in melanocytes: they overproliferate, acquire an arborized cell shape and migrate inappropriately, colonizing numerous tissues in a metalloprotease-dependent fashion. A similar effect was observed in human melanocytes in culture. Depolarization of GlyCl-expressing cells induces these drastic changes in melanocyte behavior via a serotonin-transporter-dependent increase of extracellular serotonin (5-HT). These data reveal GlyCl as a molecular marker of a sparse and heretofore unknown cell population with the ability to specifically instruct neural crest derivatives, suggest transmembrane potential as a tractable signaling modality by which somatic cells can control stem cell behavior at considerable distance, identify a new biophysical aspect of the environment that confers a neoplastic-like phenotype upon stem cell progeny, reveal a pre-neural role for serotonin and its transporter, and suggest a novel strategy for manipulating stem cell behavior.
Collapse
Affiliation(s)
- Douglas Blackiston
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
- Department of Regenerative and Developmental Biology, Forsyth Institute, Boston, MA 02115, USA
| | - Dany S. Adams
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Joan M. Lemire
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Maria Lobikin
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| | - Michael Levin
- Center for Regenerative and Developmental Biology, and Biology Department, 200 Boston Avenue, Suite 4600, Tufts University, Medford, MA 02155, USA
| |
Collapse
|
15
|
Brown PT, Herbert P, Woodruff RI. Vitellogenesis in Oncopeltus fasciatus: PLC/IP(3), DAG/PK-C pathway triggered by CaM. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1300-1305. [PMID: 20416320 DOI: 10.1016/j.jinsphys.2010.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Revised: 04/08/2010] [Accepted: 04/09/2010] [Indexed: 05/29/2023]
Abstract
In Oncopeltus fasciatus, evidence shown here indicates it is calmodulin (CaM) that activates phospholipase-C (PLC), beginning a signalling pathway necessary for endocytic uptake of yolk precursor molecules. Epithelial cell-produced CaM, transported to oocytes via gap junctions, has been shown to be required for receptor-mediated endocytic uptake of vitellogenins (Vgs, the protein precursors of yolk). To determine if CaM was directly or indirectly stimulating the phospholipase-C (PLC) signalling cascade and thus controlling Vg endocytosis we used a series of molecules known to inactivate various elements of the pathway. W-7 prevents CaM from interacting with other molecules. Neomycin isolates PIP(2) from PLC. U-73122 directly inactivates PLC. 2-APB blocks IP(3) receptors which would otherwise cause release of Ca(2+). Verapamil and CdCl(2) block Ca(2+) release channels. Staurosporin and calphostin are inhibitors of PK-C. 1-Hexadecyl-2-acetyl glycerol (HAG) binds to diacylglycerol (DAG). Through the use of these antagonists we show here that: (1) the activation of phospholipase-C in this system requires CaM. (2) Stimulated phospholipase-C converts PIP(2) into IP(3) and DAG. (3) IP(3) causes increase in cytosolic Ca(2+). (4) DAG and Ca(2+) each stimulate phosphokinase-C, resulting in endocytosis of Vgs.
Collapse
Affiliation(s)
- Patrick T Brown
- Department of Biology, West Chester University, West Chester, PA 19383, USA
| | | | | |
Collapse
|
16
|
Oviedo NJ, Morokuma J, Walentek P, Kema IP, Gu MB, Ahn JM, Hwang JS, Gojobori T, Levin M. Long-range neural and gap junction protein-mediated cues control polarity during planarian regeneration. Dev Biol 2010; 339:188-99. [PMID: 20026026 PMCID: PMC2823934 DOI: 10.1016/j.ydbio.2009.12.012] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 11/11/2009] [Accepted: 12/09/2009] [Indexed: 01/24/2023]
Abstract
Having the ability to coordinate the behavior of stem cells to induce regeneration of specific large-scale structures would have far-reaching consequences in the treatment of degenerative diseases, acute injury, and aging. Thus, identifying and learning to manipulate the sequential steps that determine the fate of new tissue within the overall morphogenetic program of the organism is fundamental. We identified novel early signals, mediated by the central nervous system and 3 innexin proteins, which determine the fate and axial polarity of regenerated tissue in planarians. Modulation of gap junction-dependent and neural signals specifically induces ectopic anterior regeneration blastemas in posterior and lateral wounds. These ectopic anterior blastemas differentiate new brains that establish permanent primary axes re-established during subsequent rounds of unperturbed regeneration. These data reveal powerful novel controls of pattern formation and suggest a constructive model linking nervous inputs and polarity determination in early stages of regeneration.
Collapse
Affiliation(s)
- Néstor J. Oviedo
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University. Suite 4600, 200 Boston Avenue, Medford. MA 02155, USA
| | - Junji Morokuma
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University. Suite 4600, 200 Boston Avenue, Medford. MA 02155, USA
| | - Peter Walentek
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University. Suite 4600, 200 Boston Avenue, Medford. MA 02155, USA
| | - Ido P. Kema
- Department of Pathology and Laboratory Medicine University Medical Center Groningen, University of Groningen The Netherlands
| | - Man Bock Gu
- College of Life Science and Biotechnology, Korea University. Seoul, Republic of Korea
| | - Joo-Myung Ahn
- College of Life Science and Biotechnology, Korea University. Seoul, Republic of Korea
| | - Jung Shan Hwang
- Center for Information Biology and DNA Data Bank of Japan National Institute of Genetics. Yata 1111, Mishima Shizuoka 411-8540. Japan
| | - Takashi Gojobori
- Center for Information Biology and DNA Data Bank of Japan National Institute of Genetics. Yata 1111, Mishima Shizuoka 411-8540. Japan
| | - Michael Levin
- Center for Regenerative and Developmental Biology and Department of Biology, Tufts University. Suite 4600, 200 Boston Avenue, Medford. MA 02155, USA
| |
Collapse
|
17
|
Zhang Y, Levin M. Particle tracking model of electrophoretic morphogen movement reveals stochastic dynamics of embryonic gradient. Dev Dyn 2009; 238:1923-35. [PMID: 19618466 DOI: 10.1002/dvdy.22016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Some developmental events rely on an electrophoretic force to produce morphogenetic gradients. To quantitatively explore the dynamics of this process, we constructed a stochastic model of an early phase of left-right patterning: serotonin movement through the gap junction-coupled blastomeres of the Xenopus embryo. Particle-tracking simulations showed that a left-right gradient is formed rapidly, quickly reaching a final stable level. The voltage difference was critical for producing a morphogen gradient of the right steepness; gap junctional connectivity and morphogen mass determined the timing of the gradient. Endogenous electrophoresis drives approximately 50% of the particles across more than one cell width, and approximately 20% can travel across half the embryo. The stochastic behavior of the resulting gradients exhibited unexpected complexity among blastomeres' morphogen content, and showed how spatiotemporal variability within individual cells resulted in robust and consistent gradients across the embryonic left-right axis. Analysis of the distribution profile of gradient gain values made quantitative predictions about the conditions that result in the observed background level of laterality defects in unperturbed frog embryos. This work provides a general model that can be used to quantitatively analyze the unexpectedly complex dynamics of morphogens in a wide variety of systems.
Collapse
Affiliation(s)
- Ying Zhang
- Center for Regenerative and Developmental Biology, The Forsyth Institute, and Department of Developmental Biology, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | | |
Collapse
|
18
|
Passage through vertebrate gap junctions of 17/18kDa molecules is primarily dependent upon molecular configuration. Tissue Cell 2009; 42:47-52. [PMID: 19726067 DOI: 10.1016/j.tice.2009.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 07/15/2009] [Accepted: 07/28/2009] [Indexed: 11/22/2022]
Abstract
In fish, amphibians and mammals, gap junctions of some cells allow passage of elongate molecules as large as 18kDa, while excluding smaller, less elongate molecules. Fluorescently labeled Calmodulin (17kDa) and fluorescently labeled Troponin-C (18kDa), when microinjected into oocytes of Danio rerio, Xenopus laevis or Mus domestica, were able to transit the gap junctions between these oocytes and the granulosa cells which surrounded them. Co-microinjected with these Ca(2+)-binding proteins, Texas-red-labeled dextran (10kDa) remained in the microinjected cell. Osteocalcin (6kDa), also a Ca(2+)-binding protein, but with a wide "V" shape proved unable to transit these gap junctions. Calmodulin, but not Troponin-C, was able to transit gap junctions of gonadotropin treated WB cells in culture. We show evidence that molecules as large as 18kDa can pass through some vertebrate gap junctions, both homologous and heterologous, and that it is primarily molecular configuration which governs gap junctional permeability.
Collapse
|
19
|
Myllykoski M, Kuczera K, Kursula P. Complex formation between calmodulin and a peptide from the intracellular loop of the gap junction protein connexin43: Molecular conformation and energetics of binding. Biophys Chem 2009; 144:130-5. [PMID: 19716642 DOI: 10.1016/j.bpc.2009.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 07/31/2009] [Accepted: 08/01/2009] [Indexed: 11/18/2022]
Abstract
Gap junctions are formed by a family of transmembrane proteins, connexins. Connexin43 is a widely studied member of the family, being ubiquitously expressed in a variety of tissues and a target of a large number of disease mutations. The intracellular loop of connexin43 has been shown to include a calmodulin binding domain, but detailed 3-dimensional data on the structure of the complex are not available. In this study, we used a synthetic peptide from this domain to reveal the conformation of the calmodulin-peptide complex by small angle X-ray scattering. Upon peptide binding, calmodulin lost its dumbbell shape, adopting a more globular conformation. We also studied the energetics of the interaction using calorimetry and computational methods. All our data indicate that calmodulin binds to the peptide from cx43 in the classical 'collapsed' conformation.
Collapse
Affiliation(s)
- Matti Myllykoski
- Department of Biochemistry, FIN-90014, University of Oulu, Oulu, Finland
| | | | | |
Collapse
|
20
|
Bohrmann J, Zimmermann J. Gap junctions in the ovary of Drosophila melanogaster: localization of innexins 1, 2, 3 and 4 and evidence for intercellular communication via innexin-2 containing channels. BMC DEVELOPMENTAL BIOLOGY 2008; 8:111. [PMID: 19038051 PMCID: PMC2631599 DOI: 10.1186/1471-213x-8-111] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2008] [Accepted: 11/27/2008] [Indexed: 12/14/2022]
Abstract
Background In the Drosophila ovary, germ-line and soma cells are interconnected via gap junctions. The main gap-junction proteins in invertebrates are members of the innexin family. In order to reveal the role that innexins play in cell-cell communication during oogenesis, we investigated the localization of innexins 1, 2, 3 and 4 using immunohistochemistry, and analyzed follicle development following channel blockade. Results We found innexin 1 predominantly localized to the baso-lateral domain of follicle cells, whereas innexin 2 is positioned apico-laterally as well as apically between follicle cells and germ-line cells. Innexin 3 was observed laterally in follicle cells and also in nurse cells, and innexin 4 was detected in the oolemma up to stage 8 and in nurse-cell membranes up to stage 12. In order to test whether innexins form channels suitable for intercellular communication, we microinjected innexin antibodies in combination with a fluorescent tracer into the oocyte of stage-10 follicles. We found that dye-coupling between oocyte and follicle cells was largely reduced by innexin-2 antibodies directed against the intracellular C-terminus as well as against the intracellular loop. Analyzing in vitro, between stages 10 and 14, the developmental capacities of follicles following microinjections of innexin-2 antibodies revealed defects in follicle-cell differentiation, nurse-cell regression, oocyte growth and choriogenesis. Conclusion Our results suggest that all analyzed innexins are involved in the formation of gap junctions in the ovary. While innexins 2 and 3 are colocalized between soma cells, innexins 2 and 4 are colocalized between soma and germ-line cells. Innexin 2 is participating in cell-cell communication via hemichannels residing in the oolemma. It is obvious that gap-junctional communication between germ-line and soma cells is essential for several processes during oogenesis.
Collapse
Affiliation(s)
- Johannes Bohrmann
- RWTH Aachen University, Institut für Biologie II, Abt. Zoologie und Humanbiologie, Kopernikusstrasse 16, 52056 Aachen, Germany.
| | | |
Collapse
|
21
|
Cieniewicz AM, Woodruff RI. Importance of molecular configuration in gap junctional permeability. JOURNAL OF INSECT PHYSIOLOGY 2008; 54:1293-1300. [PMID: 18691596 DOI: 10.1016/j.jinsphys.2008.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 06/27/2008] [Accepted: 06/27/2008] [Indexed: 05/26/2023]
Abstract
Gap junctions between insect oocytes and follicular epithelial cells allow transit of elongate Ca(2+)-binding proteins Calmodulin (CaM, 17 kDa) and Troponin-C (Trop-C, 18 kDa), but not multi-branched dextran (10 kDa) nor the Ca(2+)-binding protein Osteocalcin (Osteo, 6 kDa). By microinjection of fluorescently labeled versions of each of these molecules we were able to obtain visual evidence that, despite their lesser molecular weight, molecules with greater cross-sections were unable to transit these gap junctions, while heavier but elongate molecules could. While CaM had previously been shown to pass through gap junctions from oocytes to their surrounding epithelial cells, the ability of CaM and Trop-C to transit the gap junctions between adjacent epithelial cells had not been demonstrated. Evidence shown here demonstrates that the homologous gap junctions among epithelial cells, like the heterologous gap junctions between epithelial cells and the oocyte they surround, allow transit of elongate molecules up to at least 18 kDa. Furthermore, the evidence for four different molecules of differing molecular weights and configurations supports the hypothesis that it is molecular configuration, not chemical activity, that primarily determines the observed permeability of gap junctions to molecules 5-6 times larger than the molecular weight limit previously acknowledged.
Collapse
Affiliation(s)
- Anne M Cieniewicz
- Department of Biology, West Chester University, West Chester, PA 19383, United States
| | | |
Collapse
|
22
|
Curran JE, Woodruff RI. Passage of 17kDa calmodulin through gap junctions of three vertebrate species. Tissue Cell 2007; 39:303-9. [PMID: 17675125 DOI: 10.1016/j.tice.2007.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 05/30/2007] [Accepted: 06/11/2007] [Indexed: 11/16/2022]
Abstract
Gap junctions of some vertebrates are capable of passing the elongate molecule, calmodulin, with a molecular weight 8-17 times greater than the previously recognized size limits. Fluorescently labeled calmodulin (FCaM) (17.34 kDa) microinjected into oocytes of ovarian follicles from an amphibian, Xenopus laevis, and from two species of teleost fish, Danio rerio (Zebrafish) and Oryzias latipes (Medaka), is shown to transit their gap junctions and enter the surrounding epithelial cells. Passage of FCaM was terminated when follicles were first treated with 1 mM octanol, a molecule known to down-regulate gap junctions. There was no FCaM detected in the surrounding medium, nor did epithelial cells become fluorescent when follicles were incubated in medium containing dye. Calmodulin is well known to modulate many cytoplasmic reactions; thus, its passage through gap junctions opens possibilities of additional means by which cells may be supplied with this signaling molecule, and by which their supply may be regulated.
Collapse
Affiliation(s)
- J E Curran
- Department of Biology, West Chester University, West Chester, PA 19383-2112, USA
| | | |
Collapse
|
23
|
Ogorzałek A. Structural and functional diversification of follicular epithelium in Coreus marginatus (Coreidae: Heteroptera). ARTHROPOD STRUCTURE & DEVELOPMENT 2007; 36:209-219. [PMID: 18089100 DOI: 10.1016/j.asd.2006.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 09/25/2006] [Indexed: 05/25/2023]
Abstract
Follicular cells in Coreus marginatus are diversified into two main subpopulations of different cell morphology, ultrastructure, distribution of F-actin and ionic communication between oocyte and follicular cells. Cells forming the insert between the operculum and the bottom of the egg envelope and, subsequently, a circle of micropylar processes were retarded as compared to the developmental advancement of follicular cells in the equatorial part of ovarian follicle. Pinocytotic and vitellogenic activity in the ooplasm adjoining the insert cells were lower than in other regions. The inhibition of vitellogenesis in the neighbourhood of insert cells, which were not in ionic contact with the ooplasm, supports the hypothesis that there is a relation between follicular cell development and the regional intensity of vitellogenesis in heteropteran ovarian follicles.
Collapse
Affiliation(s)
- Antoni Ogorzałek
- Department of General Zoology, Zoological Institute, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland.
| |
Collapse
|
24
|
Mónaco ME, Villecco EI, Sánchez SS. Implication of gap junction coupling in amphibian vitellogenin uptake. ZYGOTE 2007; 15:149-57. [PMID: 17462107 DOI: 10.1017/s0967199407004133] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
SummaryThe aim of the present study was to investigate the physiological role and the expression pattern of heterologous gap junctions during Xenopus laevis vitellogenesis. Dye transfer experiments showed that there are functional gap junctions at the oocyte/follicle cell interface during the vitellogenic process and that octanol uncouples this intercellular communication. The incubation of vitellogenic oocytes in the presence of biotinylated bovine serum albumin (b-BSA) or fluorescein dextran (FDX), showed that oocytes develop stratum of newly formed yolk platelets. In octanol-treated follicles no sign of nascent yolk sphere formation was observed. Thus, experiments in which gap junctions were downregulated with octanol showed that coupled gap junctions are required for endocytic activity. RT-PCR analysis showed that the expression of connexin 43 (Cx43) was first evident at stage II of oogenesis and increased during the subsequent vitellogenic stages (III, IV and V), which would indicate that this Cx is related to the process that regulates yolk uptake. No expression changes were detected for Cx31 and Cx38 during vitellogenesis. Based on our results, we propose that direct gap junctional communication is a requirement for endocytic activity, as without the appropriate signal from surrounding epithelial cells X. laevis oocytes were unable to endocytose VTG.
Collapse
Affiliation(s)
- M E Mónaco
- Departamento de Biología del Desarrollo, Instituto Superior de Investigaciones Biológicas y Universidad Nacional de Tucumán, Tucumán, Argentina
| | | | | |
Collapse
|
25
|
Levin M. Gap junctional communication in morphogenesis. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2007; 94:186-206. [PMID: 17481700 PMCID: PMC2292839 DOI: 10.1016/j.pbiomolbio.2007.03.005] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Gap junctions permit the direct passage of small molecules from the cytosol of one cell to that of its neighbor, and thus form a system of cell-cell communication that exists alongside familiar secretion/receptor signaling. Because of the rich potential for regulation of junctional conductance, and directional and molecular gating (specificity), gap junctional communication (GJC) plays a crucial role in many aspects of normal tissue physiology. However, the most exciting role for GJC is in the regulation of information flow that takes place during embryonic development, regeneration, and tumor progression. The molecular mechanisms by which GJC establishes local and long-range instructive morphogenetic cues are just beginning to be understood. This review summarizes the current knowledge of the involvement of GJC in the patterning of both vertebrate and invertebrate systems and discusses in detail several morphogenetic systems in which the properties of this signaling have been molecularly characterized. One model consistent with existing data in the fields of vertebrate left-right patterning and anterior-posterior polarity in flatworm regeneration postulates electrophoretically guided movement of small molecule morphogens through long-range GJC paths. The discovery of mechanisms controlling embryonic and regenerative GJC-mediated signaling, and identification of the downstream targets of GJC-permeable molecules, represent exciting next areas of research in this fascinating field.
Collapse
Affiliation(s)
- Michael Levin
- Forsyth Center for Regenerative and Devlopmental Biology, Forsyth Institute, and Developmental Biology Department, Harvard School of Dental Medicine, Boston, MA 02115, USA.
| |
Collapse
|
26
|
Nogi T, Levin M. Characterization of innexin gene expression and functional roles of gap-junctional communication in planarian regeneration. Dev Biol 2005; 287:314-35. [PMID: 16243308 DOI: 10.1016/j.ydbio.2005.09.002] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2005] [Revised: 08/20/2005] [Accepted: 09/01/2005] [Indexed: 10/25/2022]
Abstract
Planaria possess remarkable powers of regeneration. After bisection, one blastema regenerates a head, while the other forms a tail. The ability of previously-adjacent cells to adopt radically different fates could be due to long-range signaling allowing determination of position relative to, and the identity of, remaining tissue. However, this process is not understood at the molecular level. Following the hypothesis that gap-junctional communication (GJC) may underlie this signaling, we cloned and characterized the expression of the Innexin gene family during planarian regeneration. Planarian innexins fall into 3 groups according to both sequence and expression. The concordance between expression-based and phylogenetic grouping suggests diversification of 3 ancestral innexin genes into the large family of planarian innexins. Innexin expression was detected throughout the animal, as well as specifically in regeneration blastemas, consistent with a role in long-range signaling relevant to specification of blastema positional identity. Exposure to a GJC-blocking reagent which does not distinguish among gap junctions composed of different Innexin proteins (is not subject to compensation or redundancy) often resulted in bipolar (2-headed) animals. Taken together, the expression data and the respecification of the posterior blastema to an anteriorized fate by GJC loss-of-function suggest that innexin-based GJC mediates instructive signaling during regeneration.
Collapse
Affiliation(s)
- Taisaku Nogi
- Department of Cytokine Biology, The Forsyth Institute, 140 The Fenway, Boston, MA 02115, USA
| | | |
Collapse
|
27
|
Atella GC, Gondim KC, Machado EA, Medeiros MN, Silva-Neto MAC, Masuda H. Oogenesis and egg development in triatomines: a biochemical approach. AN ACAD BRAS CIENC 2005; 77:405-30. [PMID: 16127549 DOI: 10.1590/s0001-37652005000300005] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In triatomines, as well as in other insects, accumulation of yolk is a process in which an extra-ovarian tissue, the fat body, produces yolk proteins that are packed in the egg. The main protein, synthesized by the fat body, which is accumulated inside the oocyte, is vitellogenin. This process is also known as vitellogenesis. There are growing evidences in triatomines that besides fat body the ovary also produces yolk proteins. The way these yolk proteins enter the oocyte will be discussed. Yolk is a complex material composed of proteins, lipids, carbohydrates and other minor components which are packed inside the oocyte in an organized manner. Fertilization triggers embryogenesis, a process where an embryo will develop. During embryogenesis the yolk will be used for the construction of a new individual, the first instar nymph. The challenge for the next decade is to understand how and where these egg proteins are used up together with their non-protein components, in pace with the genetic program of the embryo, which enables cell differentiation (early phase of embryogenesis) and embryo differentiation (late phase) inside the egg.
Collapse
Affiliation(s)
- Georgia C Atella
- Bloco H, Centro de Ciências da Saúde, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21944-590, Brazil
| | | | | | | | | | | |
Collapse
|
28
|
Woodruff RI. Calmodulin transit via gap junctions is reduced in the absence of an electric field. JOURNAL OF INSECT PHYSIOLOGY 2005; 51:843-52. [PMID: 15935371 DOI: 10.1016/j.jinsphys.2005.03.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Revised: 03/29/2005] [Accepted: 03/31/2005] [Indexed: 05/02/2023]
Abstract
Gap junctional transport of Calmodulin (CaM) from epithelial cells to insect oocytes is enhanced by alignment of the molecules via an electric field. It has recently been shown that CaM is needed for uptake of vitellogenins, is produced in the epithelial cells and reaches oocytes via gap junctions. For CaM to transit the gap junctions something must align these elongated molecules with the lumina of the gap junctions. This might be accomplished by the electric field that exists at the membrane of any cell with an Em of >0 mV. Fluorescently labeled CaM was injected into oocytes. At t=0, the epithelial cell/oocyte "fluorescence" ratio showed epithelial cells to be 24%+/-1.5% as bright as the injected oocyte. In follicles which maintained an electric field for one hour the epithelial cell/oocyte fluorescence ratio had risen to 79%+/-1.4%, while for follicles in which the field was cancelled by holding Em at 0 mV the ratio was only 45%+/-1.7%. After termination of the holding current follicles regained their original Em and their original electric field. At the end of a second hour of incubation the ratio had risen to 76%+/-1.2%, very close to what was observed in the untreated control follicles.
Collapse
Affiliation(s)
- Richard I Woodruff
- Department of Biology, West Chester University, West Chester, PA 19383, USA.
| |
Collapse
|