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Slomianka L, Amrein I, Knuesel I, Sørensen JC, Wolfer DP. Hippocampal pyramidal cells: the reemergence of cortical lamination. Brain Struct Funct 2011; 216:301-17. [PMID: 21597968 PMCID: PMC3197924 DOI: 10.1007/s00429-011-0322-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/26/2011] [Indexed: 12/16/2022]
Abstract
The increasing resolution of tract-tracing studies has led to the definition of segments along the transverse axis of the hippocampal pyramidal cell layer, which may represent functionally defined elements. This review will summarize evidence for a morphological and functional differentiation of pyramidal cells along the radial (deep to superficial) axis of the cell layer. In many species, deep and superficial sublayers can be identified histologically throughout large parts of the septotemporal extent of the hippocampus. Neurons in these sublayers are generated during different periods of development. During development, deep and superficial cells express genes (Sox5, SatB2) that also specify the phenotypes of superficial and deep cells in the neocortex. Deep and superficial cells differ neurochemically (e.g. calbindin and zinc) and in their adult gene expression patterns. These markers also distinguish sublayers in the septal hippocampus, where they are not readily apparent histologically in rat or mouse. Deep and superficial pyramidal cells differ in septal, striatal, and neocortical efferent connections. Distributions of deep and superficial pyramidal cell dendrites and studies in reeler or sparsely GFP-expressing mice indicate that this also applies to afferent pathways. Histological, neurochemical, and connective differences between deep and superficial neurons may correlate with (patho-) physiological phenomena specific to pyramidal cells at different radial locations. We feel that an appreciation of radial subdivisions in the pyramidal cell layer reminiscent of lamination in other cortical areas may be critical in the interpretation of studies of hippocampal anatomy and function.
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Affiliation(s)
- Lutz Slomianka
- Institute of Anatomy, University of Zürich, 8057 Zürich, Switzerland.
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Kim HS, Murakami R, Quintin S, Mori M, Ohkura K, Tamai KK, Labouesse M, Sakamoto H, Nishiwaki K. VAB-10 spectraplakin acts in cell and nuclear migration in Caenorhabditis elegans. Development 2011; 138:4013-23. [PMID: 21831923 PMCID: PMC3160096 DOI: 10.1242/dev.059568] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2011] [Indexed: 11/20/2022]
Abstract
Cytoskeletal regulation is important in cell migration. The Caenorhabditis elegans gonadal distal tip cells (DTCs) offer a simple model with which to investigate the mechanism of cell migration in organogenesis. Here, we report that one of the spectraplakin isoforms, VAB-10B1, plays an essential role in cell and nuclear migration of DTCs by regulating the actin and microtubule (MT) cytoskeleton. In the vab-10(tk27) mutant, which lacks VAB-10B1, alignment of filamentous (F)-actin and MTs was weakly and severely disorganized, respectively, which resulted in a failure to translocate the DTC nucleus and a premature termination of DTC migration. An MT growing-tip marker, EBP-2-GFP, revealed that polarized outgrowth of MTs towards the nuclei of migrating DTCs was strikingly impaired in tk27 animals. A vab-10 mini-gene encoding only the actin- and MT-binding domains significantly rescued the gonadal defects, suggesting that VAB-10B1 has a role in linking actin and MT filaments. These results suggest that VAB-10B1/spectraplakin regulates the polarized alignment of MTs, possibly by linking F-actin and MTs, which enables normal nuclear translocation and cell migration of DTCs.
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Affiliation(s)
- Hon-Song Kim
- Department of Bioscience, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
- RIKEN Center for Developmental Biology, Chuo-ku, Kobe 650-0047, Japan
| | - Ryoko Murakami
- RIKEN Center for Developmental Biology, Chuo-ku, Kobe 650-0047, Japan
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan
| | - Sophie Quintin
- Development and Stem Cells program, IGBMC, CNRS UMR7104/INSERM U. 964//Université de Strasbourg, Illkirch, Cedex F-67404, France
| | - Masataka Mori
- Department of Bioscience, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
| | - Kiyotaka Ohkura
- RIKEN Center for Developmental Biology, Chuo-ku, Kobe 650-0047, Japan
| | | | - Michel Labouesse
- Development and Stem Cells program, IGBMC, CNRS UMR7104/INSERM U. 964//Université de Strasbourg, Illkirch, Cedex F-67404, France
| | - Hiroshi Sakamoto
- Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodaicho, Nada-ku, Kobe 657-8501, Japan
| | - Kiyoji Nishiwaki
- Department of Bioscience, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
- RIKEN Center for Developmental Biology, Chuo-ku, Kobe 650-0047, Japan
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Wu X, Shen QT, Oristian DS, Lu CP, Zheng Q, Wang HW, Fuchs E. Skin stem cells orchestrate directional migration by regulating microtubule-ACF7 connections through GSK3β. Cell 2011; 144:341-52. [PMID: 21295697 DOI: 10.1016/j.cell.2010.12.033] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 11/01/2010] [Accepted: 12/17/2010] [Indexed: 12/17/2022]
Abstract
Homeostasis and wound healing rely on stem cells (SCs) whose activity and directed migration are often governed by Wnt signaling. In dissecting how this pathway integrates with the necessary downstream cytoskeletal dynamics, we discovered that GSK3β, a kinase inhibited by Wnt signaling, directly phosphorylates ACF7, a > 500 kDa microtubule-actin crosslinking protein abundant in hair follicle stem cells (HF-SCs). We map ACF7's GSK3β sites to the microtubule-binding domain and show that phosphorylation uncouples ACF7 from microtubules. Phosphorylation-refractile ACF7 rescues overall microtubule architecture, but phosphorylation-constitutive mutants do not. Neither mutant rescues polarized movement, revealing that phospho-regulation must be dynamic. This circuitry is physiologically relevant and depends upon polarized GSK3β inhibition at the migrating front of SCs/progeny streaming from HFs during wound repair. Moreover, only ACF7 and not GSKβ-refractile-ACF7 restore polarized microtubule-growth and SC-migration to ACF7 null skin. Our findings provide insights into how this conserved spectraplakin integrates signaling, cytoskeletal dynamics, and polarized locomotion of somatic SCs.
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Affiliation(s)
- Xiaoyang Wu
- The Howard Hughes Medical Institute, Laboratory of Mammalian Cell Biology and Development, Rockefeller University, New York, NY 10065, USA
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Gupta T, Marlow FL, Ferriola D, Mackiewicz K, Dapprich J, Monos D, Mullins MC. Microtubule actin crosslinking factor 1 regulates the Balbiani body and animal-vegetal polarity of the zebrafish oocyte. PLoS Genet 2010; 6:e1001073. [PMID: 20808893 PMCID: PMC2924321 DOI: 10.1371/journal.pgen.1001073] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 07/15/2010] [Indexed: 11/23/2022] Open
Abstract
Although of fundamental importance in developmental biology, the genetic basis for the symmetry breaking events that polarize the vertebrate oocyte and egg are largely unknown. In vertebrates, the first morphological asymmetry in the oocyte is the Balbiani body, a highly conserved, transient structure found in vertebrates and invertebrates including Drosophila, Xenopus, human, and mouse. We report the identification of the zebrafish magellan (mgn) mutant, which exhibits a novel enlarged Balbiani body phenotype and a disruption of oocyte polarity. To determine the molecular identity of the mgn gene, we positionally cloned the gene, employing a novel DNA capture method to target region-specific genomic DNA of 600 kb for massively parallel sequencing. Using this technique, we were able to enrich for the genomic region linked to our mutation within one week and then identify the mutation in mgn using massively parallel sequencing. This is one of the first successful uses of genomic DNA enrichment combined with massively parallel sequencing to determine the molecular identity of a gene associated with a mutant phenotype. We anticipate that the combination of these technologies will have wide applicability for the efficient identification of mutant genes in all organisms. We identified the mutation in mgn as a deletion in the coding sequence of the zebrafish microtubule actin crosslinking factor 1 (macf1) gene. macf1 is a member of the highly conserved spectraplakin family of cytoskeletal linker proteins, which play diverse roles in polarized cells such as neurons, muscle cells, and epithelial cells. In mgn mutants, the oocyte nucleus is mislocalized; and the Balbiani body, localized mRNAs, and organelles are absent from the periphery of the oocyte, consistent with a function for macf1 in nuclear anchoring and cortical localization. These data provide the first evidence for a role for spectraplakins in polarization of the vertebrate oocyte and egg. How the axes of the embryo are established is an important question in developmental biology. In many organisms, the axes of the embryo are established during oogenesis through the generation of a polarized egg. Very little is known regarding the mechanisms of polarity establishment and maintenance in vertebrate oocytes and eggs. We have identified a zebrafish mutant called magellan, which displays a defect in egg polarity. The gene disrupted in the magellan mutant encodes the cytoskeletal linker protein microtubule actin crosslinking factor 1 (macf1). In vertebrates, it can take years to identify the molecular nature of a mutation. We used a new technique to identify the magellan mutation, which allowed us to rapidly isolate genomic DNA linked to the mutation and sequence it. Our results describe an important new function for macf1 in polarizing the oocyte and egg and demonstrate the feasibility of this new technique for the efficient identification of mutations.
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Affiliation(s)
- Tripti Gupta
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Florence L. Marlow
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Deborah Ferriola
- Generation Biotech, Lawrenceville, New Jersey, United States of America
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Katarzyna Mackiewicz
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Johannes Dapprich
- Generation Biotech, Lawrenceville, New Jersey, United States of America
| | - Dimitri Monos
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Mary C. Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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