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A role for peroxidasin PXN-1 in aspects of C. elegans development.

Lee J, Bandyopadhyay J, Lee JI, Cho I, Park D, Cho JH - Mol. Cells (2014)

Bottom Line: A translational fusion showed that PXN-1::GFP was secreted and localized in extracellular matrix, particularly along body wall muscles and pharyngeal muscles.Various neuronal developmental defects were observed in pxn-1 mutants and in pxn-1 over-expressing animals, including handedness, branching, breakage, tangling, and defasciculation.These results suggest that pxn-1, like other peroxidasins, plays an important role throughout development.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.

ABSTRACT
The Caenorhabditis elegans peroxidasins, PXN-1 and PXN-2, are extracellular peroxidases; pxn-2 is involved in muscle-epidermal attachment during embryonic morphogenesis and in specific axon guidance. Here we investigate potential roles of the other homologue of peroxidasin, pxn-1, in C. elegans. A pxn-1 deletion mutant showed high lethality under heat-stress conditions. Using a transcriptional GFP reporter, pxn-1 expression was observed in various tissues including neurons, muscles, and hypodermis. A translational fusion showed that PXN-1::GFP was secreted and localized in extracellular matrix, particularly along body wall muscles and pharyngeal muscles. Various neuronal developmental defects were observed in pxn-1 mutants and in pxn-1 over-expressing animals, including handedness, branching, breakage, tangling, and defasciculation. These results suggest that pxn-1, like other peroxidasins, plays an important role throughout development.

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Defects of axonal navigation in pxn-1 mutants and overexpressing animals. In wild-type transgenic animals, ALN, cholinergic neuron (arrow) and DD1 and VD2 neuron [arrow head, the same applied to (B, C)] were located on the left side (A) and arrows represented GABAergic neurons (VD3-VD13 and DD2 - DD6) on the right side (B). In pxn-1 mutant and overexpressing worms (Ppxn-1::pxn-1::GFP), motor neurons [arrows in (C, D) respectively] were extended on the wrong side, the left. Inset of (D) was the enlarged image of the dotted box and the arrowheads showed over-branching of nerve ends. Representative neuron images of wild-type (E), pxn-1 mutant (F, I), Ppxn-1::pxn-1::GFP (G, H), and Phs::pxn-1::GFP (J, K): axonal breakage [arrows in (F) and open arrow in (H)], prematurely branching [arrows in (G) and (H)], tangling [arrowheads in (G, J, and K)], defasciculation [arrows in (I, J)]. Scale bars, 50 μm in A–D and E–K.
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f4-molcell-38-1-51: Defects of axonal navigation in pxn-1 mutants and overexpressing animals. In wild-type transgenic animals, ALN, cholinergic neuron (arrow) and DD1 and VD2 neuron [arrow head, the same applied to (B, C)] were located on the left side (A) and arrows represented GABAergic neurons (VD3-VD13 and DD2 - DD6) on the right side (B). In pxn-1 mutant and overexpressing worms (Ppxn-1::pxn-1::GFP), motor neurons [arrows in (C, D) respectively] were extended on the wrong side, the left. Inset of (D) was the enlarged image of the dotted box and the arrowheads showed over-branching of nerve ends. Representative neuron images of wild-type (E), pxn-1 mutant (F, I), Ppxn-1::pxn-1::GFP (G, H), and Phs::pxn-1::GFP (J, K): axonal breakage [arrows in (F) and open arrow in (H)], prematurely branching [arrows in (G) and (H)], tangling [arrowheads in (G, J, and K)], defasciculation [arrows in (I, J)]. Scale bars, 50 μm in A–D and E–K.

Mentions: We showed that pxn-1 is prominently expressed in neurons, including GABAergic and cholinergic neurons. We therefore asked whether pxn-1 has any roles in neuronal development. We used the pxn-1 promoter region (Ppxn-1::GFP) in wild-type, pxn-1 mutants, and pxn-1 over-expressing worms. In the wild-type transgenic animals, commissures (CO) at the anterior end of the body connect from the ventral nerve cord (VNC) to the dorsal nerve cord (DNC) and vice versa. In the same way, COs on the left side of the body (DD1 and VD2, arrowheads in Figs. 4A–4C) are connected in a similar manner to the right side of the body (VD3 to VD13 and DD2 to DD6, arrows in Fig. 4B). On the other hand, pxn-1 mutants displayed wrong-sided handedness of the COs (see many arrows in Fig. 4C). Moreover, pxn-1 overexpressing animals (Ppxn-1::pxn-1::GFP) showed a similar pattern, with many COs located on the wrong side (Fig. 4D). Some of them also showed over-branching at the ends of neurons (arrowheads in Fig. 4D, inset). High-magnification images illustrated prominent breakages in ALN (a cholinergic sensory neuron) in the pxn-1 mutant (arrows in Fig. 4F). Furthermore, the abnormal patterns of COs, for instance, tangled neurons (arrowheads in Fig. 4G), misguided neurons (arrows in Figs. 4G and 4H), and disconnected neurons (open arrow in Fig. 4H) observed in overexpressing animals (Ppxn-1::pxn-1, Figs. 4G and 4H) were rarely observed in wild-type animals (Fig. 4E). To confirm the role of PXN-1 in neuronal development, we ectopically expressed pxn-1 using a heat shock promoter (Phs::pxn-1::GFP). Expression of this construct alone without heat shock showed no differences compared to wild-type. However, upon heat shock, defects in neuronal navigation were clearly apparent (Figs. 4J and 4K). In animals ectopically expressing pxn-1 by heat shock, the COs not only displayed loss of direction but were also shown to tangle with each other (arrowheads in Figs. 4J and 4K). Abnormal arrangements such as defasciculated neurons were also found in the pxn-1 mutant (arrow in Fig. 4I) as well as in the animals ectopically expressing pxn-1 (arrow in Fig. 4J). Because juIs76(Punc-25:: GFP) is expressed specifically in GABAergic neurons (Jin et al., 1999), we also used juIs76 to confirm the neuronal developmental defects in the pxn-1 mutant and in over-expressing animals. Using the Punc-25::GFP we were able to confirm all the neuronal defects we observed using Ppxn-1::GFP in the pxn-1 mutant and in over-expressing animals.


A role for peroxidasin PXN-1 in aspects of C. elegans development.

Lee J, Bandyopadhyay J, Lee JI, Cho I, Park D, Cho JH - Mol. Cells (2014)

Defects of axonal navigation in pxn-1 mutants and overexpressing animals. In wild-type transgenic animals, ALN, cholinergic neuron (arrow) and DD1 and VD2 neuron [arrow head, the same applied to (B, C)] were located on the left side (A) and arrows represented GABAergic neurons (VD3-VD13 and DD2 - DD6) on the right side (B). In pxn-1 mutant and overexpressing worms (Ppxn-1::pxn-1::GFP), motor neurons [arrows in (C, D) respectively] were extended on the wrong side, the left. Inset of (D) was the enlarged image of the dotted box and the arrowheads showed over-branching of nerve ends. Representative neuron images of wild-type (E), pxn-1 mutant (F, I), Ppxn-1::pxn-1::GFP (G, H), and Phs::pxn-1::GFP (J, K): axonal breakage [arrows in (F) and open arrow in (H)], prematurely branching [arrows in (G) and (H)], tangling [arrowheads in (G, J, and K)], defasciculation [arrows in (I, J)]. Scale bars, 50 μm in A–D and E–K.
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Related In: Results  -  Collection

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f4-molcell-38-1-51: Defects of axonal navigation in pxn-1 mutants and overexpressing animals. In wild-type transgenic animals, ALN, cholinergic neuron (arrow) and DD1 and VD2 neuron [arrow head, the same applied to (B, C)] were located on the left side (A) and arrows represented GABAergic neurons (VD3-VD13 and DD2 - DD6) on the right side (B). In pxn-1 mutant and overexpressing worms (Ppxn-1::pxn-1::GFP), motor neurons [arrows in (C, D) respectively] were extended on the wrong side, the left. Inset of (D) was the enlarged image of the dotted box and the arrowheads showed over-branching of nerve ends. Representative neuron images of wild-type (E), pxn-1 mutant (F, I), Ppxn-1::pxn-1::GFP (G, H), and Phs::pxn-1::GFP (J, K): axonal breakage [arrows in (F) and open arrow in (H)], prematurely branching [arrows in (G) and (H)], tangling [arrowheads in (G, J, and K)], defasciculation [arrows in (I, J)]. Scale bars, 50 μm in A–D and E–K.
Mentions: We showed that pxn-1 is prominently expressed in neurons, including GABAergic and cholinergic neurons. We therefore asked whether pxn-1 has any roles in neuronal development. We used the pxn-1 promoter region (Ppxn-1::GFP) in wild-type, pxn-1 mutants, and pxn-1 over-expressing worms. In the wild-type transgenic animals, commissures (CO) at the anterior end of the body connect from the ventral nerve cord (VNC) to the dorsal nerve cord (DNC) and vice versa. In the same way, COs on the left side of the body (DD1 and VD2, arrowheads in Figs. 4A–4C) are connected in a similar manner to the right side of the body (VD3 to VD13 and DD2 to DD6, arrows in Fig. 4B). On the other hand, pxn-1 mutants displayed wrong-sided handedness of the COs (see many arrows in Fig. 4C). Moreover, pxn-1 overexpressing animals (Ppxn-1::pxn-1::GFP) showed a similar pattern, with many COs located on the wrong side (Fig. 4D). Some of them also showed over-branching at the ends of neurons (arrowheads in Fig. 4D, inset). High-magnification images illustrated prominent breakages in ALN (a cholinergic sensory neuron) in the pxn-1 mutant (arrows in Fig. 4F). Furthermore, the abnormal patterns of COs, for instance, tangled neurons (arrowheads in Fig. 4G), misguided neurons (arrows in Figs. 4G and 4H), and disconnected neurons (open arrow in Fig. 4H) observed in overexpressing animals (Ppxn-1::pxn-1, Figs. 4G and 4H) were rarely observed in wild-type animals (Fig. 4E). To confirm the role of PXN-1 in neuronal development, we ectopically expressed pxn-1 using a heat shock promoter (Phs::pxn-1::GFP). Expression of this construct alone without heat shock showed no differences compared to wild-type. However, upon heat shock, defects in neuronal navigation were clearly apparent (Figs. 4J and 4K). In animals ectopically expressing pxn-1 by heat shock, the COs not only displayed loss of direction but were also shown to tangle with each other (arrowheads in Figs. 4J and 4K). Abnormal arrangements such as defasciculated neurons were also found in the pxn-1 mutant (arrow in Fig. 4I) as well as in the animals ectopically expressing pxn-1 (arrow in Fig. 4J). Because juIs76(Punc-25:: GFP) is expressed specifically in GABAergic neurons (Jin et al., 1999), we also used juIs76 to confirm the neuronal developmental defects in the pxn-1 mutant and in over-expressing animals. Using the Punc-25::GFP we were able to confirm all the neuronal defects we observed using Ppxn-1::GFP in the pxn-1 mutant and in over-expressing animals.

Bottom Line: A translational fusion showed that PXN-1::GFP was secreted and localized in extracellular matrix, particularly along body wall muscles and pharyngeal muscles.Various neuronal developmental defects were observed in pxn-1 mutants and in pxn-1 over-expressing animals, including handedness, branching, breakage, tangling, and defasciculation.These results suggest that pxn-1, like other peroxidasins, plays an important role throughout development.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea.

ABSTRACT
The Caenorhabditis elegans peroxidasins, PXN-1 and PXN-2, are extracellular peroxidases; pxn-2 is involved in muscle-epidermal attachment during embryonic morphogenesis and in specific axon guidance. Here we investigate potential roles of the other homologue of peroxidasin, pxn-1, in C. elegans. A pxn-1 deletion mutant showed high lethality under heat-stress conditions. Using a transcriptional GFP reporter, pxn-1 expression was observed in various tissues including neurons, muscles, and hypodermis. A translational fusion showed that PXN-1::GFP was secreted and localized in extracellular matrix, particularly along body wall muscles and pharyngeal muscles. Various neuronal developmental defects were observed in pxn-1 mutants and in pxn-1 over-expressing animals, including handedness, branching, breakage, tangling, and defasciculation. These results suggest that pxn-1, like other peroxidasins, plays an important role throughout development.

Show MeSH
Related in: MedlinePlus