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Author Wallace, Matthew M. ♦ Kavianpour, Sarah M. ♦ Gabriele, Mark L.
Source World Health Organization (WHO)-Global Index Medicus
Content type Text
Publisher Wiley
File Format HTM / HTML
Language English
Difficulty Level Medium
Subject Domain (in DDC) Natural sciences & mathematics ♦ Chemistry & allied sciences ♦ Life sciences; biology ♦ Physiology & related subjects ♦ Biochemistry ♦ Natural history of organisms ♦ Technology ♦ Medicine & health ♦ Human anatomy, cytology, histology ♦ Human physiology ♦ Pharmacology and therapeutics ♦ Diseases
Subject Domain (in MeSH) Nervous System ♦ Anatomy ♦ Eukaryota ♦ Organisms ♦ Amino Acids, Peptides, and Proteins ♦ Chemicals and Drugs ♦ Chemical Phenomena ♦ Cell Physiological Phenomena ♦ Biological Sciences
Subject Keyword Discipline Neurology ♦ Ephrin-b2 ♦ Metabolism ♦ Inferior Colliculi ♦ Growth & Development ♦ Neurogenesis ♦ Physiology ♦ Olivary Nucleus ♦ Signal Transduction ♦ Animals ♦ Cytology ♦ Mice ♦ Mice, Inbred C57bl ♦ Mice, Mutant Strains ♦ Journal Article ♦ Research Support, N.i.h., Extramural ♦ Research Support, U.s. Gov't, Non-p.h.s.
Abstract Graded and modular expressions of Eph-ephrins are known to provide positional information for the formation of topographic maps and patterning in the developing nervous system. Previously we have shown that ephrin-B2 is expressed in a continuous gradient across the tonotopic axis of the central nucleus of the inferior colliculus (CNIC), whereas patterns are discontinuous and modular in the lateral cortex of the IC (LCIC). The present study explores the involvement of ephrin-B2 signaling in the development of projections to the CNIC and LCIC arising from the lateral superior olivary nuclei (LSO) prior to hearing onset. Anterograde and retrograde fluorescent tracing methods in neonatal fixed tissue preparations were used to compare topographic mapping and the establishment of LSO layers/modules in wild-type and ephrin-B2(lacZ/+) mice (severely compromised reverse signaling). At birth, pioneer LSO axons occupy the ipsilateral IC in both groups but are delayed contralaterally in ephrin-B2(lacZ/+) mutants. By the onset of hearing, both wild-type and mutant projections form discernible layers bilaterally in the CNIC and modular arrangements within the ipsilateral LCIC. In contrast, ephrin-B2(lacZ/+) mice lack a reliable topography in LSO-IC projections, suggesting that fully functional ephrin-B2 reverse signaling is required for normal projection mapping. Taken together, these ephrin-B2 findings paired with known coexpression of EphA4 suggest the importance of these signaling proteins in establishing functional auditory circuits prior to experience.
Description Country affiliation: United States
Author Affiliation: Wallace MM ( Department of Biology, MSC 7801, James Madison University, Harrisonburg, Virginia 22807, USA.)
ISSN 00219967
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Reading ♦ Research ♦ Self Learning
Interactivity Type Expositive
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2013-05-01
Publisher Place United States
e-ISSN 10969861
Journal Journal of Comparative Neurology
Volume Number 521
Issue Number 7


Source: WHO-Global Index Medicus