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Gene expression profiles in Rana pirica tadpoles following exposure to a predation threat.

Mori T, Yanagisawa Y, Kitani Y, Sugiyama M, Kishida O, Nishimura K - BMC Genomics (2015)

Bottom Line: Thirteen genes were induced specifically by dragonfly larvae, nine others were salamander-specific, and sixteen were induced by both.Functional analyses indicated that some of the genes induced by dragonfly larvae caused an increase in laminins necessary for cell adhesion in the extracellular matrix.The connective tissue of tadpoles exposed to larval salamanders may be looser.

View Article: PubMed Central - PubMed

Affiliation: Department of Marine Science and Resources, Nihon University College of Bioresource Sciences, Kameino 1866, Fujisawa, 252-0880, Japan. mori.tsukasa@nihon-u.ac.jp.

ABSTRACT

Background: Rana pirica tadpoles show morphological changes in response to a predation threat: larvae of the dragonfly Aeshna nigroflava induce heightened tail depth, whereas larval salamander Hynobius retardatus induce a bulgy morphology with heightened tail depth. Although both predators induce similar tail morphologies, it is possible that there are functional differences between these tail morphs.

Results: Here, we performed a discriminant microarray analysis using Xenopus laevis genome arrays to compare tail tissues of control and predator-exposed tadpoles. We identified 9 genes showing large-scale changes in their expression profile: ELAV-like1, methyltransferase like 7A, dolichyl-phosphate mannosyltransferase, laminin subunit beta-1, gremlin 1, BCL6 corepressor-like 1, and three genes of unknown identity. A further 80 genes showed greater than 5 fold differences in expression after exposure to dragonfly larvae and 81 genes showed altered expression after exposure to larval salamanders. Predation-threat responsive genes were identified by selecting genes that reverted to control levels of expression following removal of the predator. Thirteen genes were induced specifically by dragonfly larvae, nine others were salamander-specific, and sixteen were induced by both. Functional analyses indicated that some of the genes induced by dragonfly larvae caused an increase in laminins necessary for cell adhesion in the extracellular matrix. The higher expression of gremlin 1 and HIF1a genes after exposure to dragonfly larvae indicated an in vivo hypoxic reaction, while down-regulation of syndecan-2 may indicate impairment of angiogenesis. Exposure to larval salamanders caused down-regulation of XCIRP-1, which is known to inhibit expression of adhesion molecules; the tadpoles showed reduced expression of cα(E)-catenin, small muscle protein, dystrophin, and myosin light chain genes.

Conclusion: The connective tissue of tadpoles exposed to larval salamanders may be looser. The differences in gene expression profiles induced by the two predators suggest that there are functional differences between the altered tail tissues of the two groups of tadpoles.

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The nine genes selected by discriminant analysis. (a) The hierarchical clustering of the nine genes was created using single linkage with Euclidean distance. Numbers 1–3 indicate array chip number. Abbreviations as in Figure 1. (b) Averaged gene expression profile obtained by the discriminant analysis.
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Fig3: The nine genes selected by discriminant analysis. (a) The hierarchical clustering of the nine genes was created using single linkage with Euclidean distance. Numbers 1–3 indicate array chip number. Abbreviations as in Figure 1. (b) Averaged gene expression profile obtained by the discriminant analysis.

Mentions: The nine genes selected by this discriminant analysis are summarized in Table 1 and also shown in the hierarchical combined tree in Figure 3a. Clusters were created using single linkage method with Euclidean distance, and the clusters indicated clear separation of experimental condition such as control, −Drago and so on. This validates the selection method for the nine genes. Further, the same separation was also obtained using 2 other clustering methods: group average method with Euclidean distances and Ward’s method with squared Euclidean distances. The results indicated that expression profiles of the 9 genes are robust.Figure 3


Gene expression profiles in Rana pirica tadpoles following exposure to a predation threat.

Mori T, Yanagisawa Y, Kitani Y, Sugiyama M, Kishida O, Nishimura K - BMC Genomics (2015)

The nine genes selected by discriminant analysis. (a) The hierarchical clustering of the nine genes was created using single linkage with Euclidean distance. Numbers 1–3 indicate array chip number. Abbreviations as in Figure 1. (b) Averaged gene expression profile obtained by the discriminant analysis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4403775&req=5

Fig3: The nine genes selected by discriminant analysis. (a) The hierarchical clustering of the nine genes was created using single linkage with Euclidean distance. Numbers 1–3 indicate array chip number. Abbreviations as in Figure 1. (b) Averaged gene expression profile obtained by the discriminant analysis.
Mentions: The nine genes selected by this discriminant analysis are summarized in Table 1 and also shown in the hierarchical combined tree in Figure 3a. Clusters were created using single linkage method with Euclidean distance, and the clusters indicated clear separation of experimental condition such as control, −Drago and so on. This validates the selection method for the nine genes. Further, the same separation was also obtained using 2 other clustering methods: group average method with Euclidean distances and Ward’s method with squared Euclidean distances. The results indicated that expression profiles of the 9 genes are robust.Figure 3

Bottom Line: Thirteen genes were induced specifically by dragonfly larvae, nine others were salamander-specific, and sixteen were induced by both.Functional analyses indicated that some of the genes induced by dragonfly larvae caused an increase in laminins necessary for cell adhesion in the extracellular matrix.The connective tissue of tadpoles exposed to larval salamanders may be looser.

View Article: PubMed Central - PubMed

Affiliation: Department of Marine Science and Resources, Nihon University College of Bioresource Sciences, Kameino 1866, Fujisawa, 252-0880, Japan. mori.tsukasa@nihon-u.ac.jp.

ABSTRACT

Background: Rana pirica tadpoles show morphological changes in response to a predation threat: larvae of the dragonfly Aeshna nigroflava induce heightened tail depth, whereas larval salamander Hynobius retardatus induce a bulgy morphology with heightened tail depth. Although both predators induce similar tail morphologies, it is possible that there are functional differences between these tail morphs.

Results: Here, we performed a discriminant microarray analysis using Xenopus laevis genome arrays to compare tail tissues of control and predator-exposed tadpoles. We identified 9 genes showing large-scale changes in their expression profile: ELAV-like1, methyltransferase like 7A, dolichyl-phosphate mannosyltransferase, laminin subunit beta-1, gremlin 1, BCL6 corepressor-like 1, and three genes of unknown identity. A further 80 genes showed greater than 5 fold differences in expression after exposure to dragonfly larvae and 81 genes showed altered expression after exposure to larval salamanders. Predation-threat responsive genes were identified by selecting genes that reverted to control levels of expression following removal of the predator. Thirteen genes were induced specifically by dragonfly larvae, nine others were salamander-specific, and sixteen were induced by both. Functional analyses indicated that some of the genes induced by dragonfly larvae caused an increase in laminins necessary for cell adhesion in the extracellular matrix. The higher expression of gremlin 1 and HIF1a genes after exposure to dragonfly larvae indicated an in vivo hypoxic reaction, while down-regulation of syndecan-2 may indicate impairment of angiogenesis. Exposure to larval salamanders caused down-regulation of XCIRP-1, which is known to inhibit expression of adhesion molecules; the tadpoles showed reduced expression of cα(E)-catenin, small muscle protein, dystrophin, and myosin light chain genes.

Conclusion: The connective tissue of tadpoles exposed to larval salamanders may be looser. The differences in gene expression profiles induced by the two predators suggest that there are functional differences between the altered tail tissues of the two groups of tadpoles.

Show MeSH
Related in: MedlinePlus