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Ruijter JM, Soufan AT, Hagoort J, Moorman AFM. Molecular imaging of the embryonic heart: Fables and facts on 3D imaging of gene expression patterns. ACTA ACUST UNITED AC 2005; 72:224-40. [PMID: 15495186 DOI: 10.1002/bdrc.20018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Molecular imaging, which is the three-dimensional (3D) visualization of gene expression patterns, is indispensable for the study of the function of genes in cardiac development. The instrumentation, as well as the development of specific contrast agents for molecular imaging, has shown spectacular advances in the last decade. In this review, the spatial resolutions, contrast agents, and applications of these imaging methods in the field of cardiac embryology are discussed. Apart from 3D reconstructions from histological sections, not many of these methods have been applied in embryological research. This review shows that, for most methods, neither the spatial resolutions nor the specificity and applicability of the contrast agents are adequate for the reliable imaging of specific gene expression at the microscopic resolution required for embryological studies of small organs like the developing heart. Although a 3D reconstruction from sections will always suffer from imperfections, the resulting reconstructions meet the aim of most biological studies, especially since the original microscopic images are linked. With respect to imaging of gene expression, only histological sections and laser scanning microscopy provide the required resolution and specificity at the tissue and cellular level. Episcopic fluorescence image capturing and optical projection tomography are being used for microscopic phenotyping and lineage analysis, and both show potential for detailed molecular imaging. Other methods can be used very efficiently in rapid evaluation of biological experiments and high-throughput screens of large-scale gene expression profiling efforts when high spatial resolution is not required.
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Affiliation(s)
- Jan M Ruijter
- Department of Anatomy and Embryology, Experimental and Molecular Cardiology Group, Academic Medical Center, Amsterdam, The Netherlands.
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52
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Rhee JM, Oda-Ishii I, Passamaneck YJ, Hadjantonakis AK, Di Gregorio A. Live imaging and morphometric analysis of embryonic development in the ascidianCiona intestinalis. Genesis 2005; 43:136-47. [PMID: 16267822 DOI: 10.1002/gene.20164] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The ascidian Ciona intestinalis is one of the model organisms of choice for comparative investigations of chordate development and for unraveling the molecular mechanisms underlying morphogenesis and cell fate specification. Taking advantage of the availability of various genetically encoded fluorescent proteins and of defined cis-regulatory elements, we combined transient transgenesis with laser scanning confocal imaging to acquire and quantitate 3D time-lapse data from living Ciona embryos. We used Ciona tissue-specific enhancers to drive expression of spectrally distinct fluorescent protein reporters to label and simultaneously visualize axially and paraxially positioned mesodermal derivatives, as well as neural precursors in individual embryos. We observed morphogenetic movements, without perturbing development, from the early gastrula throughout the larval stage, including gastrulation, neurulation, convergent extension of the presumptive notochord, and tail elongation. These multidimensional data allowed us to establish a reference system of metrics to quantify key developmental events including blastopore closure and muscle extension. The approach we describe can be used to document morphogenetic cell and tissue rearrangements in living embryos and paves the way for a live digitized anatomical atlas of Ciona.
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Affiliation(s)
- Jerry M Rhee
- Developmental Biology Program, Sloan-Kettering Institute, New York, New York 10021, USA
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53
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Ewald AJ, Peyrot SM, Tyszka JM, Fraser SE, Wallingford JB. Regional requirements for Dishevelled signaling duringXenopusgastrulation: separable effects on blastopore closure, mesendoderm internalization and archenteron formation. Development 2004; 131:6195-209. [PMID: 15548584 DOI: 10.1242/dev.01542] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During amphibian gastrulation, the embryo is transformed by the combined actions of several different tissues. Paradoxically, many of these morphogenetic processes can occur autonomously in tissue explants, yet the tissues in intact embryos must interact and be coordinated with one another in order to accomplish the major goals of gastrulation: closure of the blastopore to bring the endoderm and mesoderm fully inside the ectoderm, and generation of the archenteron. Here, we present high-resolution 3D digital datasets of frog gastrulae, and morphometrics that allow simultaneous assessment of the progress of convergent extension, blastopore closure and archenteron formation in a single embryo. To examine how the diverse morphogenetic engines work together to accomplish gastrulation, we combined these tools with time-lapse analysis of gastrulation, and examined both wild-type embryos and embryos in which gastrulation was disrupted by the manipulation of Dishevelled (Xdsh)signaling. Remarkably, although inhibition of Xdsh signaling disrupted both convergent extension and blastopore closure, mesendoderm internalization proceeded very effectively in these embryos. In addition, much of archenteron elongation was found to be independent of Xdsh signaling, especially during the second half of gastrulation. Finally, even in normal embryos, we found a surprising degree of dissociability between the various morphogenetic processes that occur during gastrulation. Together, these data highlight the central role of PCP signaling in governing distinct events of Xenopusgastrulation, and suggest that the loose relationship between morphogenetic processes may have facilitated the evolution of the wide variety of gastrulation mechanisms seen in different amphibian species.
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Affiliation(s)
- Andrew J Ewald
- Department of Biology and Biological Imaging Center, California Institute of Technology, Pasadena, CA 91125, USA
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54
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Abstract
The study of embryonic events using different animal model systems is crucial for gaining insights into human development and birth defects. Biological imaging plays a major role in this effort by providing a spatiotemporal framework to link complex cell movements with molecular data. However, depending on the age of the embryo and the location of a morphogenetic event, visualization often requires the design of novel culture and imaging techniques. One of the primary model systems for biological imaging is the avian embryo, due to its accessibility to manipulation, relatively two-dimensional morphogenesis early on, and viability when grown in culture. Significant work in avian embryo culture and cell labeling, together with advances in imaging technology, now make it possible to monitor many developmental events within the period from egg laying to hatching. Here, we present the latest in avian developmental imaging, focusing on cell labeling, embryo culture, and imaging technologies.
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Affiliation(s)
- Paul M Kulesa
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.
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Denk W, Horstmann H. Serial block-face scanning electron microscopy to reconstruct three-dimensional tissue nanostructure. PLoS Biol 2004; 2:e329. [PMID: 15514700 PMCID: PMC524270 DOI: 10.1371/journal.pbio.0020329] [Citation(s) in RCA: 1048] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2004] [Accepted: 07/29/2004] [Indexed: 11/20/2022] Open
Abstract
Three-dimensional (3D) structural information on many length scales is of central importance in biological research. Excellent methods exist to obtain structures of molecules at atomic, organelles at electron microscopic, and tissue at light-microscopic resolution. A gap exists, however, when 3D tissue structure needs to be reconstructed over hundreds of micrometers with a resolution sufficient to follow the thinnest cellular processes and to identify small organelles such as synaptic vesicles. Such 3D data are, however, essential to understand cellular networks that, particularly in the nervous system, need to be completely reconstructed throughout a substantial spatial volume. Here we demonstrate that datasets meeting these requirements can be obtained by automated block-face imaging combined with serial sectioning inside the chamber of a scanning electron microscope. Backscattering contrast is used to visualize the heavy-metal staining of tissue prepared using techniques that are routine for transmission electron microscopy. Low-vacuum (20–60 Pa H2O) conditions prevent charging of the uncoated block face. The resolution is sufficient to trace even the thinnest axons and to identify synapses. Stacks of several hundred sections, 50–70 nm thick, have been obtained at a lateral position jitter of typically under 10 nm. This opens the possibility of automatically obtaining the electron-microscope-level 3D datasets needed to completely reconstruct the connectivity of neuronal circuits. A new method combines automated imaging with serial sectioning inside the chamber of a scanning electron microscope
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Affiliation(s)
- Winfried Denk
- Max Planck Institute for Medical Research, Heidelberg, Germany.
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56
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Megason SG, Fraser SE. Digitizing life at the level of the cell: high-performance laser-scanning microscopy and image analysis for in toto imaging of development. Mech Dev 2003; 120:1407-20. [PMID: 14623446 DOI: 10.1016/j.mod.2003.07.005] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The field of biological imaging is progressing at an amazing rate. Advances in both laser-scanning microscopy and green fluorescent protein (GFP) technology are combining to make possible imaging-based approaches for studying developmental mechanisms that were previously impossible. Modern confocal and multi-photon microscopes are pushing the envelope of speed, sensitivity, spectral resolution, and depth resolution to allow in vivo imaging of whole, live embryos at cellular resolution over extended periods of time. In toto imaging, in which nearly every cell in an embryo or tissue can be tracked through space and time during development, may become a standard technique for small transparent embryos such as zebrafish and early stage chick and mouse embryos. GFP and its spectral variants can be used to mark a wide range of in vivo biological information for in toto imaging including gene expression patterns, mutant phenotypes, and protein subcellular localization patterns. Combining in toto imaging and GFP transgenic approaches on a large scale may usher in an explosion of in vivo, developmental data as has happened in the past several years with genomic data. There are significant challenges that must be met to reach these goals. This paper will discuss the current state-of-the-art, the challenges, and the prospects of in toto imaging in the areas of imaging, image analysis, and informatics.
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Affiliation(s)
- Sean G Megason
- Biological Imaging Center, Beckman Institute and Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
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Solnica-Krezel L, Eaton S. Embryo morphogenesis: getting down to cells and molecules. Development 2003; 130:4229-33. [PMID: 12900440 DOI: 10.1242/dev.00693] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Cole MJ, Pirity M, Hadjantonakis AK. Shedding light on bioscience. Symposium on Optical Imaging: Applications to Biology and Medicine. EMBO Rep 2003; 4:838-43. [PMID: 12947418 PMCID: PMC1326361 DOI: 10.1038/sj.embor.embor924] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2003] [Accepted: 07/22/2003] [Indexed: 11/09/2022] Open
Abstract
This dynamic symposium, held on 11-16 February 2003 in Taos, New Mexico, was the first Keystone meeting to focus on optical techniques and their use in biology and medicine. It was organized by D. Becker, D. Farkas and S. Fraser and attracted almost 100 participants from both academia and industry. Fluorescence imaging and its applications, ranging from nano-bioscience to small-animal imaging and imaging of disease progression in humans, were the main topics, with opportunities for further discussion in the cantinas of the town and on the ski slopes of Taos mountain.
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Affiliation(s)
- Mary J. Cole
- Department of Physiology, Genentech Inc.,
1 DNA Way, San Francisco, California
94080, USA
| | - Melinda Pirity
- Department of Molecular Genetics, Albert Einstein
College of Medicine, 1300 Morris Park Avenue,
Bronx, New York 10461, USA
- Institute of Genetics, Biological Research Center
of the Hungarian Academy of Sciences, PO Box 521, Szeged
6701, Hungary
| | - Anna-Katerina Hadjantonakis
- Department of Genetics and Development, College
of Physicians and Surgeons of Columbia University, 701 West 168th
Street, New York, New York 10032,
USA
- Tel: +1 212 305 4791; Fax: +1 212 923 2090;
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Abstract
In vivo methods to detect antigen-specific T cell responses at the single-cell level have greatly increased our knowledge of how the immune system works. However, most of these approaches have been confined to analysis of lymphoid tissues. Recently, the development of imaging techniques capable of simultaneously monitoring all the tissues of the body has led to the realization that antigen-experienced T cells reside in non-lymphoid tissues and may play a vital role in protecting the host against pathogens. Therefore, single-cell imaging at the level of the whole organism is needed to fully understand the dynamics of protective immunity.
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Affiliation(s)
- R Lee Reinhardt
- Department of Microbiology and the Center for Immunology, University of Minnesota, MMC 334, 420 Delaware St SE, Minneapolis, Minnesota 55455, USA.
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Soufan AT, Ruijter JM, van den Hoff MJB, de Boer PAJ, Hagoort J, Moorman AFM. Three-dimensional reconstruction of gene expression patterns during cardiac development. Physiol Genomics 2003; 13:187-95. [PMID: 12746463 DOI: 10.1152/physiolgenomics.00182.2002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The study of the genetic regulation of embryonic development requires the three-dimensional (3D) mapping of gene expression at the microscopic level. Despite the recent burst in the number of methods focusing on 3D reconstruction of embryonic specimens, an adequate and accessible 3D reconstruction protocol for the visualization of patterns of gene expression is lacking. In this communication we describe a protocol that was developed for the 3D visualization of patterns of gene expression determined by in situ hybridization (ISH) on serial sections. The method still requires tissue sectioning, due to penetration limits of the specific staining agents into whole embryo preparations. With regard to expenditure of resources, i.e., hardware, software, and time, the protocol is relatively undemanding. Because the variation between specimens requires the visualization of multiple specimens per stage, it was decided to "do more, less well." The current protocol, therefore, results in reconstructions of sufficient, but not the highest, quality. The use of the protocol is demonstrated on a series of serially sectioned mouse hearts, ranging from embryonic day 8.5 to 14.5. The myocardium of the hearts was identified by ISH using a mixture of specific mRNA probes and reconstructed.
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Affiliation(s)
- Alexandre T Soufan
- Experimental and Molecular Cardiology Group, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands
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61
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Ruffins SW, Jacobs RE, Fraser SE. Towards a Tralfamadorian view of the embryo: multidimensional imaging of development. Curr Opin Neurobiol 2002; 12:580-6. [PMID: 12367639 DOI: 10.1016/s0959-4388(02)00366-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Biological problems such as embryonic development require tools to follow cell and tissue movements as well as the distribution of active genes. A variety of emerging imaging techniques offer the capability of fully rendering the three-dimensional structure of the embryo, and some offer the possibility of following changes directly over time. The data sets that result offer both new insights and new challenges. A framework of digital atlases will soon offer the integration of different imaging modalities and permit users to interact with multidimensional data sets.
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Affiliation(s)
- Seth W Ruffins
- Biological Imaging Center, Beckman Institute and Division of Biology, California Institute of Technology, Pasadena, California 91125, USA
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