Limits...
Microarray analysis identifies candidate genes for key roles in coral development.

Grasso LC, Maindonald J, Rudd S, Hayward DC, Saint R, Miller DJ, Ball EE - BMC Genomics (2008)

Bottom Line: Of 5081 unique peptide coding genes, 1084 were differentially expressed (P <or= 0.05) in comparisons between four different stages of coral development, spanning key developmental transitions.One surprising finding is that some of these genes have clear counterparts in higher animals but are not present in the closely-related sea anemone Nematostella.Secondly, coral-specific processes (i.e. traits which distinguish corals from their close relatives) may be analogous to similar processes in distantly related organisms.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for the Molecular Genetics of Development, Research School of Biological Sciences, Australian National University, Canberra, Australia. lauretta.grasso@anu.edu.au

ABSTRACT

Background: Anthozoan cnidarians are amongst the simplest animals at the tissue level of organization, but are surprisingly complex and vertebrate-like in terms of gene repertoire. As major components of tropical reef ecosystems, the stony corals are anthozoans of particular ecological significance. To better understand the molecular bases of both cnidarian development in general and coral-specific processes such as skeletogenesis and symbiont acquisition, microarray analysis was carried out through the period of early development - when skeletogenesis is initiated, and symbionts are first acquired.

Results: Of 5081 unique peptide coding genes, 1084 were differentially expressed (P

Conclusion: This study is the first large-scale investigation of developmental gene expression for any cnidarian, and has provided candidate genes for key roles in many aspects of coral biology, including calcification, metamorphosis and symbiont uptake. One surprising finding is that some of these genes have clear counterparts in higher animals but are not present in the closely-related sea anemone Nematostella. Secondly, coral-specific processes (i.e. traits which distinguish corals from their close relatives) may be analogous to similar processes in distantly related organisms. This first large-scale application of microarray analysis demonstrates the potential of this approach for investigating many aspects of coral biology, including the effects of stress and disease.

Show MeSH

Related in: MedlinePlus

Sequence comparison and whole mount in situ hybridization of lectin coding genes A036-E7 and A049-E7. (A). Alignment of A036-E7 and A049-E7 amino acid sequences with C. echinata CEL-III reveal that they are 82.1% identical (90.6% similar) to one another and 50.4% (65.1%) and 48% (64%) to CEL-III respectively. Black boxes represent identities and grey shaded boxes similarities. Localisation of A036-E7 (B) and A049-E7 (C) transcripts (dark purple) in presettlement planula larvae (1), metamorphosing larvae (2), and postsettlement polyps viewed from the oral side (3), and in cross section with the mouth pointing upward (4). Expression in the oral ectoderm is consistent with a role in metamorphosis or defence against pathogenic microorganisms.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2629781&req=5

Figure 3: Sequence comparison and whole mount in situ hybridization of lectin coding genes A036-E7 and A049-E7. (A). Alignment of A036-E7 and A049-E7 amino acid sequences with C. echinata CEL-III reveal that they are 82.1% identical (90.6% similar) to one another and 50.4% (65.1%) and 48% (64%) to CEL-III respectively. Black boxes represent identities and grey shaded boxes similarities. Localisation of A036-E7 (B) and A049-E7 (C) transcripts (dark purple) in presettlement planula larvae (1), metamorphosing larvae (2), and postsettlement polyps viewed from the oral side (3), and in cross section with the mouth pointing upward (4). Expression in the oral ectoderm is consistent with a role in metamorphosis or defence against pathogenic microorganisms.

Mentions: A search for genes encoding lectin domains in clusters II, III and IV identified six unigenes, two of which, A036-E7 and A049-E7, have significant overall similarity to a haemolytic lectin from sea cucumber. They lack clear Nematostella (or Hydra) counterparts, but a homologous gene is present in the Caribbean coral, Acropora palmata [15]. The two A. millepora proteins are 82.1% identical to one another (Figure 3A), and 50.4% and 48% identical to Cucumaria echinata CEL-III [16] respectively. These were amongst the most highly represented of the differentially expressed unigenes (A036-E7 was represented by 13 ESTs and A049-E7 by 4) and, based on their expression patterns, they are candidates for roles in metamorphosis. In situ hybridization (Figure 3B, C) revealed that both A036-E7 and A049-E7 are expressed in a subpopulation of ectodermal cells in the oral half of the larva (Figure 3B1-2; C1-2). In the post-settlement primary polyp they are exclusively expressed orally on the side that is exposed to the environment, the other, non-expressing side being against the substratum (Figure 3B3-4; C3-4). C. echinata CEL-III functions as an oligomer, apparently causing osmotic rupture of cell membranes after attachment to membrane-bound sugars [16,17], and their high sequence similarity suggests similar roles for the two Acropora proteins in cell recognition and lysis for tissue remodelling during metamorphosis. Alternatively, expression on the exposed surface of the polyp is also consistent with a role in self-defence, and could indicate a function in lysis of invading microorganisms by a similar mechanism, as suggested by Kouzuma et al [17].


Microarray analysis identifies candidate genes for key roles in coral development.

Grasso LC, Maindonald J, Rudd S, Hayward DC, Saint R, Miller DJ, Ball EE - BMC Genomics (2008)

Sequence comparison and whole mount in situ hybridization of lectin coding genes A036-E7 and A049-E7. (A). Alignment of A036-E7 and A049-E7 amino acid sequences with C. echinata CEL-III reveal that they are 82.1% identical (90.6% similar) to one another and 50.4% (65.1%) and 48% (64%) to CEL-III respectively. Black boxes represent identities and grey shaded boxes similarities. Localisation of A036-E7 (B) and A049-E7 (C) transcripts (dark purple) in presettlement planula larvae (1), metamorphosing larvae (2), and postsettlement polyps viewed from the oral side (3), and in cross section with the mouth pointing upward (4). Expression in the oral ectoderm is consistent with a role in metamorphosis or defence against pathogenic microorganisms.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2629781&req=5

Figure 3: Sequence comparison and whole mount in situ hybridization of lectin coding genes A036-E7 and A049-E7. (A). Alignment of A036-E7 and A049-E7 amino acid sequences with C. echinata CEL-III reveal that they are 82.1% identical (90.6% similar) to one another and 50.4% (65.1%) and 48% (64%) to CEL-III respectively. Black boxes represent identities and grey shaded boxes similarities. Localisation of A036-E7 (B) and A049-E7 (C) transcripts (dark purple) in presettlement planula larvae (1), metamorphosing larvae (2), and postsettlement polyps viewed from the oral side (3), and in cross section with the mouth pointing upward (4). Expression in the oral ectoderm is consistent with a role in metamorphosis or defence against pathogenic microorganisms.
Mentions: A search for genes encoding lectin domains in clusters II, III and IV identified six unigenes, two of which, A036-E7 and A049-E7, have significant overall similarity to a haemolytic lectin from sea cucumber. They lack clear Nematostella (or Hydra) counterparts, but a homologous gene is present in the Caribbean coral, Acropora palmata [15]. The two A. millepora proteins are 82.1% identical to one another (Figure 3A), and 50.4% and 48% identical to Cucumaria echinata CEL-III [16] respectively. These were amongst the most highly represented of the differentially expressed unigenes (A036-E7 was represented by 13 ESTs and A049-E7 by 4) and, based on their expression patterns, they are candidates for roles in metamorphosis. In situ hybridization (Figure 3B, C) revealed that both A036-E7 and A049-E7 are expressed in a subpopulation of ectodermal cells in the oral half of the larva (Figure 3B1-2; C1-2). In the post-settlement primary polyp they are exclusively expressed orally on the side that is exposed to the environment, the other, non-expressing side being against the substratum (Figure 3B3-4; C3-4). C. echinata CEL-III functions as an oligomer, apparently causing osmotic rupture of cell membranes after attachment to membrane-bound sugars [16,17], and their high sequence similarity suggests similar roles for the two Acropora proteins in cell recognition and lysis for tissue remodelling during metamorphosis. Alternatively, expression on the exposed surface of the polyp is also consistent with a role in self-defence, and could indicate a function in lysis of invading microorganisms by a similar mechanism, as suggested by Kouzuma et al [17].

Bottom Line: Of 5081 unique peptide coding genes, 1084 were differentially expressed (P <or= 0.05) in comparisons between four different stages of coral development, spanning key developmental transitions.One surprising finding is that some of these genes have clear counterparts in higher animals but are not present in the closely-related sea anemone Nematostella.Secondly, coral-specific processes (i.e. traits which distinguish corals from their close relatives) may be analogous to similar processes in distantly related organisms.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for the Molecular Genetics of Development, Research School of Biological Sciences, Australian National University, Canberra, Australia. lauretta.grasso@anu.edu.au

ABSTRACT

Background: Anthozoan cnidarians are amongst the simplest animals at the tissue level of organization, but are surprisingly complex and vertebrate-like in terms of gene repertoire. As major components of tropical reef ecosystems, the stony corals are anthozoans of particular ecological significance. To better understand the molecular bases of both cnidarian development in general and coral-specific processes such as skeletogenesis and symbiont acquisition, microarray analysis was carried out through the period of early development - when skeletogenesis is initiated, and symbionts are first acquired.

Results: Of 5081 unique peptide coding genes, 1084 were differentially expressed (P

Conclusion: This study is the first large-scale investigation of developmental gene expression for any cnidarian, and has provided candidate genes for key roles in many aspects of coral biology, including calcification, metamorphosis and symbiont uptake. One surprising finding is that some of these genes have clear counterparts in higher animals but are not present in the closely-related sea anemone Nematostella. Secondly, coral-specific processes (i.e. traits which distinguish corals from their close relatives) may be analogous to similar processes in distantly related organisms. This first large-scale application of microarray analysis demonstrates the potential of this approach for investigating many aspects of coral biology, including the effects of stress and disease.

Show MeSH
Related in: MedlinePlus