1
|
Blackburn ATM, Miller RK. Modeling congenital kidney diseases in Xenopus laevis. Dis Model Mech 2019; 12:12/4/dmm038604. [PMID: 30967415 PMCID: PMC6505484 DOI: 10.1242/dmm.038604] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Congenital anomalies of the kidney and urinary tract (CAKUT) occur in ∼1/500 live births and are a leading cause of pediatric kidney failure. With an average wait time of 3-5 years for a kidney transplant, the need is high for the development of new strategies aimed at reducing the incidence of CAKUT and preserving renal function. Next-generation sequencing has uncovered a significant number of putative causal genes, but a simple and efficient model system to examine the function of CAKUT genes is needed. Xenopus laevis (frog) embryos are well-suited to model congenital kidney diseases and to explore the mechanisms that cause these developmental defects. Xenopus has many advantages for studying the kidney: the embryos develop externally and are easily manipulated with microinjections, they have a functional kidney in ∼2 days, and 79% of identified human disease genes have a verified ortholog in Xenopus. This facilitates high-throughput screening of candidate CAKUT-causing genes. In this Review, we present the similarities between Xenopus and mammalian kidneys, highlight studies of CAKUT-causing genes in Xenopus and describe how common kidney diseases have been modeled successfully in this model organism. Additionally, we discuss several molecular pathways associated with kidney disease that have been studied in Xenopus and demonstrate why it is a useful model for studying human kidney diseases. Summary: Understanding how congenital kidney diseases arise is imperative to their treatment. Using Xenopus as a model will aid in elucidating kidney development and congenital kidney diseases.
Collapse
Affiliation(s)
- Alexandria T M Blackburn
- Pediatric Research Center, Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genetics and Epigenetics, Houston, TX 77030, USA
| | - Rachel K Miller
- Pediatric Research Center, Department of Pediatrics, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA .,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genetics and Epigenetics, Houston, TX 77030, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Biochemistry and Cell Biology Houston, Houston, TX 77030, USA.,Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| |
Collapse
|
2
|
Haeri M, Zhuo X, Haeri M, Knox BE. Retinal tissue preparation for high-resolution live imaging of photoreceptors expressing multiple transgenes. MethodsX 2018; 5:1140-1147. [PMID: 30302320 PMCID: PMC6174271 DOI: 10.1016/j.mex.2018.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 03/09/2018] [Indexed: 11/30/2022] Open
Abstract
Live imaging has become the favorite method in recent years to study the protein transport, localization and dynamics in live cells. Protein transport is extremely essential for proper function of photoreceptors. Aberration in the proper transport of proteins gives rise to the loss of photoreceptor and blindness. On the other hand, the ease of generation of transgenic Xenopus laevis tadpoles and the advantage of high resolution live confocal imaging provide new insight into understanding protein dynamics in photoreceptors. There are several steps for quantifying and visualizing fluorescently tagged proteins in photoreceptors starting with assembly of plasmids, generation of transgenic tadpoles, preparation of retinal tissues, imaging the transgenic photoreceptors and finally analyzing the recorded data. The focus of this manuscript is to describe how to prepare retinal tissues suited for live cell imaging and provide our readers with a tutorial video. We also give a summary of steps leading to a successful experiment that might be designed for imaging the ultrastructures of photoreceptors, the expression of two or more different fluorescently tagged proteins, their localization, distribution, or protein dynamics within photoreceptors. •Retinal tissue live imaging demonstrates the ultrastructures of photoreceptors.•High resolution live confocal imaging provides new insight into understanding the pathophysiology of photoreceptors.
Collapse
Affiliation(s)
- Mohammad Haeri
- Departments of Neuroscience & Physiology, and Ophthalmology, SUNY Upstate Medical University, Syracuse, NY, United States.,Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, United States.,Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Department of Pathology & Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Xinming Zhuo
- Departments of Neuroscience & Physiology, and Ophthalmology, SUNY Upstate Medical University, Syracuse, NY, United States.,Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Morteza Haeri
- Department of Chemical & Biomedical Engineering, Syracuse University, Syracuse, NY, United States
| | - Barry E Knox
- Departments of Neuroscience & Physiology, and Ophthalmology, SUNY Upstate Medical University, Syracuse, NY, United States
| |
Collapse
|
3
|
Juárez-Morales JL, Martinez-De Luna RI, Zuber ME, Roberts A, Lewis KE. Zebrafish transgenic constructs label specific neurons in Xenopus laevis spinal cord and identify frog V0v spinal neurons. Dev Neurobiol 2017; 77:1007-1020. [PMID: 28188691 DOI: 10.1002/dneu.22490] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/26/2017] [Accepted: 02/08/2017] [Indexed: 12/19/2022]
Abstract
A correctly functioning spinal cord is crucial for locomotion and communication between body and brain but there are fundamental gaps in our knowledge of how spinal neuronal circuitry is established and functions. To understand the genetic program that regulates specification and functions of this circuitry, we need to connect neuronal molecular phenotypes with physiological analyses. Studies using Xenopus laevis tadpoles have increased our understanding of spinal cord neuronal physiology and function, particularly in locomotor circuitry. However, the X. laevis tetraploid genome and long generation time make it difficult to investigate how neurons are specified. The opacity of X. laevis embryos also makes it hard to connect functional classes of neurons and the genes that they express. We demonstrate here that Tol2 transgenic constructs using zebrafish enhancers that drive expression in specific zebrafish spinal neurons label equivalent neurons in X. laevis and that the incorporation of a Gal4:UAS amplification cassette enables cells to be observed in live X. laevis tadpoles. This technique should enable the molecular phenotypes, morphologies and physiologies of distinct X. laevis spinal neurons to be examined together in vivo. We have used an islet1 enhancer to label Rohon-Beard sensory neurons and evx enhancers to identify V0v neurons, for the first time, in X. laevis spinal cord. Our work demonstrates the homology of spinal cord circuitry in zebrafish and X. laevis, suggesting that future work could combine their relative strengths to elucidate a more complete picture of how vertebrate spinal cord neurons are specified, and function to generate behavior. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1007-1020, 2017.
Collapse
Affiliation(s)
- José L Juárez-Morales
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244.,Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - Reyna I Martinez-De Luna
- The Center for Vision Research, Department of Ophthalmology, SUNY Upstate Medical University, Institute for Human Performance, 505 Irving Ave. Syracuse, New York, 13210
| | - Michael E Zuber
- The Center for Vision Research, Department of Ophthalmology, SUNY Upstate Medical University, Institute for Human Performance, 505 Irving Ave. Syracuse, New York, 13210
| | - Alan Roberts
- School of Biological Sciences, Bristol University, 24 Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Katharine E Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244
| |
Collapse
|
4
|
Rhodopsin Trafficking and Mistrafficking: Signals, Molecular Components, and Mechanisms. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 132:39-71. [PMID: 26055054 DOI: 10.1016/bs.pmbts.2015.02.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Rhodopsin is a seven-transmembrane G protein-coupled receptor (GPCR) and is the main component of the photoreceptor outer segment (OS), a ciliary compartment essential for vision. Because the OSs are incapable of protein synthesis, rhodopsin must first be synthesized in the inner segments (ISs) and subsequently trafficked across the connecting cilia to the OSs where it participates in the phototransduction cascade. Rapid turnover of the OS necessitates a high rate of synthesis and efficient trafficking of rhodopsin to the cilia. This cilia-targeting mechanism is shared among other ciliary-localized GPCRs. In this review, we will discuss the process of rhodopsin trafficking from the IS to the OS beginning with the trafficking signals present on the protein. Starting from the endoplasmic reticulum and the Golgi apparatus within the IS, we will cover the molecular components assisting the biogenesis and the proper sorting. We will also review the confirmed binding and interacting partners that help target rhodopsin toward the connecting cilium as well as the cilia-localized components which direct proteins into the proper compartments of the OS. While rhodopsin is the most critical and abundant component of the photoreceptor OS, mutations in the rhodopsin gene commonly lead to its mislocalization within the photoreceptors. In addition to covering the trafficking patterns of rhodopsin, we will also review some of the most common rhodopsin mutants which cause mistrafficking and subsequent death of photoreceptors. Toward the goal of understanding the pathogenesis, three major mechanisms of aberrant trafficking as well as putative mechanisms of photoreceptor degeneration will be discussed.
Collapse
|