Regulation of central neuron synaptic targeting by the Drosophila POU protein, Acj6

Development ◽  
2000 ◽  
Vol 127 (11) ◽  
pp. 2395-2405
Author(s):  
S.J. Certel ◽  
P.J. Clyne ◽  
J.R. Carlson ◽  
W.A. Johnson
Keyword(s):  
Motor Neurons ◽  
Synapse Formation ◽  
Target Selection ◽  
Adult Brain ◽  
Synaptic Targeting ◽  
Amino Terminal ◽  
Pou Domain ◽  
Alternatively Spliced ◽  
The Central Nervous System ◽  
Class Iv

Mutations in the Drosophila class IV POU domain gene, abnormal chemosensory jump 6 (acj6), have previously been shown to cause physiological deficits in odor sensitivity. However, loss of Acj6 function also has a severe detrimental effect upon coordinated larval and adult movement that cannot be explained by the simple loss in odorant detection. In addition to olfactory sensory neurons, Acj6 is expressed in a distinct subset of postmitotic interneurons in the central nervous system from late embryonic to adult stages. In the larval and adult brain, Acj6 is highly expressed in central brain, optic and antennal lobe neurons. Loss of Acj6 function in larval optic lobe neurons results in disorganized retinal axon targeting and synapse selection. Furthermore, the lamina neurons themselves exhibit disorganized synaptic arbors in the medulla of acj6 mutant pupal brains, suggesting that Acj6 may play a role in regulating synaptic connections or structure. To further test this hypothesis, we misexpressed two Acj6 isoforms in motor neurons where they are not normally found. The two Acj6 isoforms are produced from alternatively spliced acj6 transcripts, resulting in significant structural differences in the amino-terminal POU IV box. Acj6 misexpression caused marked alterations at the neuromuscular junction, with contrasting effects upon nerve terminal branching and synapse formation associated with specific Acj6 isoforms. Our results suggest that the class IV POU domain factor, Acj6, may play an important role in regulating synaptic target selection by central neurons and that the amino-terminal POU IV box is important for regulation of Acj6 activity.

scholarly journals Isoform-specific anti-MeCP2 antibodies confirm that expression of the e1 isoform strongly predominates in the brain

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 204 ◽  
Author(s):  
Lara Kaddoum ◽  
Nicolas Panayotis ◽  
Honoré Mazarguil ◽  
Giuseppina Giglia-Mari ◽  
Jean Christophe Roux ◽  
...  
Keyword(s):  
Western Blot ◽  
Rett Syndrome ◽  
Polyclonal Antibodies ◽  
Protein Isoforms ◽  
Amino Terminal ◽  
Mouse Tissues ◽  
Alternatively Spliced ◽  
The Central Nervous System ◽  
The One ◽  
The Brain

Rett syndrome is a neurological disorder caused by mutations in the MECP2 gene.  MeCP2 transcripts are alternatively spliced to generate two protein isoforms (MeCP2_e1 and MeCP2_e2) that differ at their N-termini. Whilst mRNAs for both forms are expressed ubiquitously, the one for MeCP2_e1 is more abundant than for MeCP2_e2 in the central nervous system. In transfected cells, both protein isoforms are nuclear and colocalize with densely methylated heterochromatic foci. With a view to understanding the physiological contribution of each isoform, and their respective roles in the pathogenesis of Rett syndrome, we set out to generate isoform-specific anti-MeCP2 antibodies. To this end, we immunized rabbits against the peptides corresponding to the short amino-terminal portions that are different between the two isoforms. The polyclonal antibodies thus obtained specifically detected their respective isoforms of MeCP2 in Neuro2a (N2A) cells transfected to express either form. Both antisera showed comparable sensitivities when used for Western blot or immunofluorescence, and were highly specific for their respective isoform. When those antibodies were used on mouse tissues, specific signals were easily detected for Mecp2_e1, whilst Mecp2_e2 was very difficult to detect by Western blot, and even more so by immunofluorescence. Our results thus suggest that brain cells express low amounts of the Mecp2-e2 isoform. Our findings are compatible with recent reports showing that MeCP2_e2 is dispensable for healthy brain function, and that it may be involved in the regulation of neuronal apoptosis and embryonic development.

scholarly journals Mechanisms Underlying Target Selectivity for Cell Types and Subcellular Domains in Developing Neocortical Circuits

2021 ◽  
Vol 15 ◽  
Author(s):  
Alan Y. Gutman-Wei ◽  
Solange P. Brown
Keyword(s):  
Cerebral Cortex ◽  
Synapse Formation ◽  
Target Selection ◽  
Neuronal Cell ◽  
Cell Types ◽  
Synaptic Function ◽  
Morphological Properties ◽  
Cell Type ◽  
Cortical Function ◽  
Synaptic Targeting

The cerebral cortex contains numerous neuronal cell types, distinguished by their molecular identity as well as their electrophysiological and morphological properties. Cortical function is reliant on stereotyped patterns of synaptic connectivity and synaptic function among these neuron types, but how these patterns are established during development remains poorly understood. Selective targeting not only of different cell types but also of distinct postsynaptic neuronal domains occurs in many brain circuits and is directed by multiple mechanisms. These mechanisms include the regulation of axonal and dendritic guidance and fine-scale morphogenesis of pre- and postsynaptic processes, lineage relationships, activity dependent mechanisms and intercellular molecular determinants such as transmembrane and secreted molecules, many of which have also been implicated in neurodevelopmental disorders. However, many studies of synaptic targeting have focused on circuits in which neuronal processes target different lamina, such that cell-type-biased connectivity may be confounded with mechanisms of laminar specificity. In the cerebral cortex, each cortical layer contains cell bodies and processes from intermingled neuronal cell types, an arrangement that presents a challenge for the development of target-selective synapse formation. Here, we address progress and future directions in the study of cell-type-biased synaptic targeting in the cerebral cortex. We highlight challenges to identifying developmental mechanisms generating stereotyped patterns of intracortical connectivity, recent developments in uncovering the determinants of synaptic target selection during cortical synapse formation, and current gaps in the understanding of cortical synapse specificity.

scholarly journals How prolonged expression of Hunchback, a temporal transcription factor, re-wires locomotor circuits

2019 ◽  
Author(s):  
Julia L. Meng ◽  
Zarion D. Marshall ◽  
Meike Lobb-Rabe ◽  
Ellie S. Heckscher
Keyword(s):  
Transcription Factor ◽  
Stem Cell ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Synapse Formation ◽  
Target Selection ◽  
Neuromuscular Synapse ◽  
Biomedical Intervention ◽  
Neuronal Stem Cell ◽  
Dendrite Morphogenesis

Abstract:In many CNS regions, neuronal birth timing is associated with circuit membership. In Drosophila larvae, we show U motor neurons are a temporal cohort—a set of non-identical, contiguously-born neurons from a single neuronal stem cell that contribute to the same circuit. We prolong expression of a temporal transcription factor, Hunchback, to increase the number of U motor neurons with early-born molecular identities. On the circuit level, this expands and re-wires the U motor neuron temporal cohort. On the cell biological level, we find novel roles for Hunchback in motor neuron target selection, neuromuscular synapse formation, dendrite morphogenesis, and behavior. These data provide insight into the relationship between stem cell and circuit, show that Hunchback is a potent regulator of circuit assembly, and suggest that temporal transcription factors are molecules that could be altered during evolution or biomedical intervention for the generation of novel circuits.

Heterogeneity and Proliferative and Differential Regulators of NG2-glia in Physiological and Pathological States

2020 ◽  
Vol 27 (37) ◽  
pp. 6384-6406 ◽  
Author(s):  
Zuo Zhang ◽  
Hongli Zhou ◽  
Jiyin Zhou
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Physiological State ◽  
Critical Role ◽  
Adult Brain ◽  
Pathological State ◽  
Peripheral Neurons ◽  
Neuronal Synapses ◽  
The Central Nervous System ◽  
Rapid Modulation

NG2-glia, also called Oligodendrocyte Precursor Cells (OPCs), account for approximately 5%-10% of the cells in the developing and adult brain and constitute the fifth major cell population in the central nervous system. NG2-glia express receptors and ion channels involved in rapid modulation of neuronal activities and signaling with neuronal synapses, which have functional significance in both physiological and pathological states. NG2-glia participate in quick signaling with peripheral neurons via direct synaptic touches in the developing and mature central nervous system. These distinctive glia perform the unique function of proliferating and differentiating into oligodendrocytes in the early developing brain, which is critical for axon myelin formation. In response to injury, NG2-glia can proliferate, migrate to the lesions, and differentiate into oligodendrocytes to form new myelin sheaths, which wrap around damaged axons and result in functional recovery. The capacity of NG2-glia to regulate their behavior and dynamics in response to neuronal activity and disease indicate their critical role in myelin preservation and remodeling in the physiological state and in repair in the pathological state. In this review, we provide a detailed summary of the characteristics of NG2-glia, including their heterogeneity, the regulators of their proliferation, and the modulators of their differentiation into oligodendrocytes.

scholarly journals The Skeletal Muscle Emerges as a New Disease Target in Amyotrophic Lateral Sclerosis

2021 ◽  
Vol 11 (7) ◽  
pp. 671
Author(s):  
Oihane Pikatza-Menoio ◽  
Amaia Elicegui ◽  
Xabier Bengoetxea ◽  
Neia Naldaiz-Gastesi ◽  
Adolfo López de Munain ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amyotrophic Lateral Sclerosis ◽  
Muscle Tissue ◽  
Motor Neurons ◽  
Neurodegenerative Disorder ◽  
Disease Onset ◽  
Fine Tuning ◽  
Current State ◽  
The Central Nervous System ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that leads to progressive degeneration of motor neurons (MNs) and severe muscle atrophy without effective treatment. Most research on ALS has been focused on the study of MNs and supporting cells of the central nervous system. Strikingly, the recent observations of pathological changes in muscle occurring before disease onset and independent from MN degeneration have bolstered the interest for the study of muscle tissue as a potential target for delivery of therapies for ALS. Skeletal muscle has just been described as a tissue with an important secretory function that is toxic to MNs in the context of ALS. Moreover, a fine-tuning balance between biosynthetic and atrophic pathways is necessary to induce myogenesis for muscle tissue repair. Compromising this response due to primary metabolic abnormalities in the muscle could trigger defective muscle regeneration and neuromuscular junction restoration, with deleterious consequences for MNs and thereby hastening the development of ALS. However, it remains puzzling how backward signaling from the muscle could impinge on MN death. This review provides a comprehensive analysis on the current state-of-the-art of the role of the skeletal muscle in ALS, highlighting its contribution to the neurodegeneration in ALS through backward-signaling processes as a newly uncovered mechanism for a peripheral etiopathogenesis of the disease.

scholarly journals Anatomy and Neural Pathways Modulating Distinct Locomotor Behaviors in Drosophila Larva

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 90
Author(s):  
Swetha B. M. Gowda ◽  
Safa Salim ◽  
Farhan Mohammad
Keyword(s):  
Motor Neurons ◽  
Model Systems ◽  
Neural Pathways ◽  
Animal Movements ◽  
Drosophila Larvae ◽  
The Central Nervous System ◽  
Drosophila Larva ◽  
Locomotor Behaviors ◽  
Basic Level

The control of movements is a fundamental feature shared by all animals. At the most basic level, simple movements are generated by coordinated neural activity and muscle contraction patterns that are controlled by the central nervous system. How behavioral responses to various sensory inputs are processed and integrated by the downstream neural network to produce flexible and adaptive behaviors remains an intense area of investigation in many laboratories. Due to recent advances in experimental techniques, many fundamental neural pathways underlying animal movements have now been elucidated. For example, while the role of motor neurons in locomotion has been studied in great detail, the roles of interneurons in animal movements in both basic and noxious environments have only recently been realized. However, the genetic and transmitter identities of many of these interneurons remains unclear. In this review, we provide an overview of the underlying circuitry and neural pathways required by Drosophila larvae to produce successful movements. By improving our understanding of locomotor circuitry in model systems such as Drosophila, we will have a better understanding of how neural circuits in organisms with different bodies and brains lead to distinct locomotion types at the organism level. The understanding of genetic and physiological components of these movements types also provides directions to understand movements in higher organisms.

scholarly journals Targeted axonal import (TAxI) peptide delivers functional proteins into spinal cord motor neurons after peripheral administration

2016 ◽  
Vol 113 (9) ◽  
pp. 2514-2519 ◽  
Author(s):  
Drew L. Sellers ◽  
Jamie M. Bergen ◽  
Russell N. Johnson ◽  
Heidi Back ◽  
John M. Ravits ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neurons ◽  
Unmet Need ◽  
Nerve Roots ◽  
Biologic Drugs ◽  
Administration Routes ◽  
Macromolecular Drugs ◽  
The Central Nervous System ◽  
Clinical Potential

A significant unmet need in treating neurodegenerative disease is effective methods for delivery of biologic drugs, such as peptides, proteins, or nucleic acids into the central nervous system (CNS). To date, there are no operative technologies for the delivery of macromolecular drugs to the CNS via peripheral administration routes. Using an in vivo phage-display screen, we identify a peptide, targeted axonal import (TAxI), that enriched recombinant bacteriophage accumulation and delivered protein cargo into spinal cord motor neurons after intramuscular injection. In animals with transected peripheral nerve roots, TAxI delivery into motor neurons after peripheral administration was inhibited, suggesting a retrograde axonal transport mechanism for delivery into the CNS. Notably, TAxI-Cre recombinase fusion proteins induced selective recombination and tdTomato-reporter expression in motor neurons after intramuscular injections. Furthermore, TAxI peptide was shown to label motor neurons in the human tissue. The demonstration of a nonviral-mediated delivery of functional proteins into the spinal cord establishes the clinical potential of this technology for minimally invasive administration of CNS-targeted therapeutics.

Characterization of Myoelectric Signals Using System Identification Techniques

2004 ◽  
Author(s):  
Jeffrey T. Bingham ◽  
Marco P. Schoen
Keyword(s):  
System Identification ◽  
Motor Neurons ◽  
Current System ◽  
Electrical Potential ◽  
Computer Software ◽  
The Body ◽  
Myoelectric Signals ◽  
Hand Motion ◽  
The Central Nervous System

Human muscle motion is initiated in the central nervous system where a nervous signal travels through the body and the motor neurons excite the muscles to move. These signals, termed myoelectric signals, can be measured on the surface of the skin as an electrical potential. By analyzing these signals it is possible to determine the muscle actions the signals elicit, and thus can be used in manipulating smart prostheses and teleoperation of machinery. Due to the randomness of myoelectric signals, identification of the signals is not complete, therefore the goal of this project is to complete a study of the characterization of one set of hand motions using current system identification methods. The gripping motion of the hand and the corresponding myoelectric signals are measured and the data captured with a personal computer. Using computer software the captured data are processed and finally subjected to several system identification routines. Using this technique it is possible to construct a mathematical model that correlates the myoelectric signals with the matching hand motion.

scholarly journals Multifaceted roles of microRNAs: From motor neuron generation in embryos to degeneration in spinal muscular atrophy

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Tai-Heng Chen ◽  
Jun-An Chen
Keyword(s):  
Nervous System ◽  
Neurodegenerative Diseases ◽  
Spinal Muscular Atrophy ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Muscular Atrophy ◽  
Cell Types ◽  
Spinal Motor Neurons ◽  
Potential Applications ◽  
The Central Nervous System

Two crucial questions in neuroscience are how neurons establish individual identity in the developing nervous system and why only specific neuron subtypes are vulnerable to neurodegenerative diseases. In the central nervous system, spinal motor neurons serve as one of the best-characterized cell types for addressing these two questions. In this review, we dissect these questions by evaluating the emerging role of regulatory microRNAs in motor neuron generation in developing embryos and their potential contributions to neurodegenerative diseases such as spinal muscular atrophy (SMA). Given recent promising results from novel microRNA-based medicines, we discuss the potential applications of microRNAs for clinical assessments of SMA disease progression and treatment.

scholarly journals Identification of protein products encoded by the proto-oncogene int-1.

1987 ◽  
Vol 7 (11) ◽  
pp. 3971-3977 ◽  
Author(s):  
A M Brown ◽  
J Papkoff ◽  
Y K Fung ◽  
G M Shackleford ◽  
H E Varmus
Keyword(s):  
Retroviral Vectors ◽  
Mammary Epithelial ◽  
In Vitro Translation ◽  
Amino Terminal ◽  
Induced Tumors ◽  
Epithelial Cell Lines ◽  
Tumor Virus ◽  
Transforming Activity ◽  
The Central Nervous System

The proto-oncogene int-1 is activated by adjacent insertions of proviral DNA in mouse mammary tumor virus-induced tumors and has transforming activity in certain mammary epithelial cell lines. The gene is normally expressed in the central nervous system of mid-gestational embryos and in the adult testis. We raised antibodies against synthetic int-1 peptides and used these to identify protein products of the gene in cells transfected or infected with retroviral vectors expressing int-1. Four protein species of 36,000, 38,000, 40,000, and 42,000 Mr were immunoprecipitated by antibodies against two different int-1 peptides and were not present in control cells. Partial degradation with V8 protease showed the four species to be structurally related to each other and to int-1 polypeptide synthesized in vitro. Treatment of the cells with tunicamycin prevented the appearance of all but the 36,000-Mr species, suggesting that the slower-migrating forms are glycosylated derivatives. The unglycosylated 36,000-Mr species migrated faster in polyacrylamide gels than the in vitro translation product of int-1 and has probably undergone cleavage of an amino-terminal signal peptide.

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