Carboxypeptidase A6 in zebrafish development and implications for VIth cranial nerve pathfinding.

Carboxypeptidase A6 (CPA6) is an extracellular protease that cleaves carboxy-terminal hydrophobic amino acids and has been implicated in the defective innervation of the lateral rectus muscle by the VIth cranial nerve in Duane syndrome. In order to investigate the role of CPA6 in development, in par...

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Main Authors: Peter J Lyons, Leung-hang Ma, Robert Baker, Lloyd D Fricker
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2010-09-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0012967&type=printable
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author Peter J Lyons
Leung-hang Ma
Robert Baker
Lloyd D Fricker
author_facet Peter J Lyons
Leung-hang Ma
Robert Baker
Lloyd D Fricker
author_sort Peter J Lyons
collection DOAJ
description Carboxypeptidase A6 (CPA6) is an extracellular protease that cleaves carboxy-terminal hydrophobic amino acids and has been implicated in the defective innervation of the lateral rectus muscle by the VIth cranial nerve in Duane syndrome. In order to investigate the role of CPA6 in development, in particular its potential role in axon guidance, the zebrafish ortholog was identified and cloned. Zebrafish CPA6 was secreted and interacted with the extracellular matrix where it had a neutral pH optimum and specificity for C-terminal hydrophobic amino acids. Transient mRNA expression was found in newly formed somites, pectoral fin buds, the stomodeum and a conspicuous condensation posterior to the eye. Markers showed this tissue was not myogenic in nature. Rather, the CPA6 localization overlapped with a chondrogenic site which subsequently forms the walls of a myodome surrounding the lateral rectus muscle. No other zebrafish CPA gene exhibited a similar expression profile. Morpholino-mediated knockdown of CPA6 combined with retrograde labeling and horizontal eye movement analyses demonstrated that deficiency of CPA6 alone did not affect either VIth nerve development or function in the zebrafish. We suggest that mutations in other genes and/or enhancer elements, together with defective CPA6 expression, may be required for altered VIth nerve pathfinding. If mutations in CPA6 contribute to Duane syndrome, our results also suggest that Duane syndrome can be a chondrogenic rather than a myogenic or neurogenic developmental disorder.
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spelling doaj-art-567ec9113aac4fd2bff337243ccdd9032025-08-20T02:01:58ZengPublic Library of Science (PLoS)PLoS ONE1932-62032010-09-0159e1296710.1371/journal.pone.0012967Carboxypeptidase A6 in zebrafish development and implications for VIth cranial nerve pathfinding.Peter J LyonsLeung-hang MaRobert BakerLloyd D FrickerCarboxypeptidase A6 (CPA6) is an extracellular protease that cleaves carboxy-terminal hydrophobic amino acids and has been implicated in the defective innervation of the lateral rectus muscle by the VIth cranial nerve in Duane syndrome. In order to investigate the role of CPA6 in development, in particular its potential role in axon guidance, the zebrafish ortholog was identified and cloned. Zebrafish CPA6 was secreted and interacted with the extracellular matrix where it had a neutral pH optimum and specificity for C-terminal hydrophobic amino acids. Transient mRNA expression was found in newly formed somites, pectoral fin buds, the stomodeum and a conspicuous condensation posterior to the eye. Markers showed this tissue was not myogenic in nature. Rather, the CPA6 localization overlapped with a chondrogenic site which subsequently forms the walls of a myodome surrounding the lateral rectus muscle. No other zebrafish CPA gene exhibited a similar expression profile. Morpholino-mediated knockdown of CPA6 combined with retrograde labeling and horizontal eye movement analyses demonstrated that deficiency of CPA6 alone did not affect either VIth nerve development or function in the zebrafish. We suggest that mutations in other genes and/or enhancer elements, together with defective CPA6 expression, may be required for altered VIth nerve pathfinding. If mutations in CPA6 contribute to Duane syndrome, our results also suggest that Duane syndrome can be a chondrogenic rather than a myogenic or neurogenic developmental disorder.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0012967&type=printable
spellingShingle Peter J Lyons
Leung-hang Ma
Robert Baker
Lloyd D Fricker
Carboxypeptidase A6 in zebrafish development and implications for VIth cranial nerve pathfinding.
PLoS ONE
title Carboxypeptidase A6 in zebrafish development and implications for VIth cranial nerve pathfinding.
title_full Carboxypeptidase A6 in zebrafish development and implications for VIth cranial nerve pathfinding.
title_fullStr Carboxypeptidase A6 in zebrafish development and implications for VIth cranial nerve pathfinding.
title_full_unstemmed Carboxypeptidase A6 in zebrafish development and implications for VIth cranial nerve pathfinding.
title_short Carboxypeptidase A6 in zebrafish development and implications for VIth cranial nerve pathfinding.
title_sort carboxypeptidase a6 in zebrafish development and implications for vith cranial nerve pathfinding
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0012967&type=printable
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