Limits...
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.

Show MeSH

Related in: MedlinePlus

Hierarchical clustering of 81 known genes showing greater than 5 fold difference to control that were induced by larval salamanders, and the selection of salamander-specific genes. (a) Expression profiles of the genes using hierarchical clustering by single linkage with Euclidean distance. (b) Expression profiles of the 81 genes and (c) procedure for selection of predation-threat responsive genes. Genes surrounded by blue boxes are salamander-specific and genes surrounded by green boxes are commonly observed after the dragonfly treatment.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig7: Hierarchical clustering of 81 known genes showing greater than 5 fold difference to control that were induced by larval salamanders, and the selection of salamander-specific genes. (a) Expression profiles of the genes using hierarchical clustering by single linkage with Euclidean distance. (b) Expression profiles of the 81 genes and (c) procedure for selection of predation-threat responsive genes. Genes surrounded by blue boxes are salamander-specific and genes surrounded by green boxes are commonly observed after the dragonfly treatment.

Mentions: Standard methods were used to determine fold changes in expression of genes following exposure to a predator. We set a threshold change of over 5 fold compared to the control and identified 316 and 301 genes that were induced by exposure to dragonfly larvae or larval salamanders, respectively (Figure 5a and b). These data are also described in Additional file 5: Table S3 and Additional file 6: Table S4. Of these genes, the identities of only 80 and 81 genes, respectively, were known and these were selected as predator-responsive genes. The expression profiles of these genes were compared by a hierarchical clustering analysis using single linkage with Euclidean distance. This analysis indicated that gene #72 (targeting protein for Xklp2) showed an 11.5 fold increase in expression and gene #23 (UPF0534 protein) showed an 11.3 fold decrease in expression compared to control after exposure to a dragonfly larva (Figure 6). Gene #72 (Frzb-1 protein) showed a 12.7 fold increase in expression and gene #21 (14-3-3 protein) a 10.9 fold decrease compared to control after exposure to a larval salamander (Figure 7).Figure 5


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)

Hierarchical clustering of 81 known genes showing greater than 5 fold difference to control that were induced by larval salamanders, and the selection of salamander-specific genes. (a) Expression profiles of the genes using hierarchical clustering by single linkage with Euclidean distance. (b) Expression profiles of the 81 genes and (c) procedure for selection of predation-threat responsive genes. Genes surrounded by blue boxes are salamander-specific and genes surrounded by green boxes are commonly observed after the dragonfly treatment.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig7: Hierarchical clustering of 81 known genes showing greater than 5 fold difference to control that were induced by larval salamanders, and the selection of salamander-specific genes. (a) Expression profiles of the genes using hierarchical clustering by single linkage with Euclidean distance. (b) Expression profiles of the 81 genes and (c) procedure for selection of predation-threat responsive genes. Genes surrounded by blue boxes are salamander-specific and genes surrounded by green boxes are commonly observed after the dragonfly treatment.
Mentions: Standard methods were used to determine fold changes in expression of genes following exposure to a predator. We set a threshold change of over 5 fold compared to the control and identified 316 and 301 genes that were induced by exposure to dragonfly larvae or larval salamanders, respectively (Figure 5a and b). These data are also described in Additional file 5: Table S3 and Additional file 6: Table S4. Of these genes, the identities of only 80 and 81 genes, respectively, were known and these were selected as predator-responsive genes. The expression profiles of these genes were compared by a hierarchical clustering analysis using single linkage with Euclidean distance. This analysis indicated that gene #72 (targeting protein for Xklp2) showed an 11.5 fold increase in expression and gene #23 (UPF0534 protein) showed an 11.3 fold decrease in expression compared to control after exposure to a dragonfly larva (Figure 6). Gene #72 (Frzb-1 protein) showed a 12.7 fold increase in expression and gene #21 (14-3-3 protein) a 10.9 fold decrease compared to control after exposure to a larval salamander (Figure 7).Figure 5

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