Molecular biology studies on the coelacanth: a review
- Modisakeng, Keoagile W, Amemiya, Chris T, Dorrington, Rosemary A, Blatch, Gregory L
- Authors: Modisakeng, Keoagile W , Amemiya, Chris T , Dorrington, Rosemary A , Blatch, Gregory L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6466 , http://hdl.handle.net/10962/d1005795
- Description: The discovery of the African coelacanth in 1938 and subsequently the Indonesian coelacanth in 1998 has resulted in a keen interest in molecular studies on the coelacanth. A major focus has been on the phylogenetic position of the coelacanth. Lobe-finned fish such as the coelacanth are thought to be at the base of the evolutionary branch of fish leading to tetrapods. These studies have further aimed to resolve the phylogenetic relationship of extant lobe-finned fish (two coelacanth species and the lungfishes) to vertebrates. Notwithstanding the lack of readily accessible good-quality coelacanth tissue, several major contributions to coelacanth molecular studies and biology have been possible. The mitochondrial genome sequences of both species of the coelacanth suggest that they diverged from one another 40–30 million years ago. A number of large gene families such as the HOX, protocadherin and heat shock protein clusters have been characterized. Furthermore, the recent successful construction of a large-insert (150–200 kilobase) genomic library of the Indonesian coelacanth will prove to be an invaluable tool in both comparative and functional genomics. Here we summarize and evaluate the current status of molecular research, published and databased, for both the African (Latimeria chalumnae) and the Indonesian (Latimeria menadoensis) coelacanth.
- Full Text:
- Authors: Modisakeng, Keoagile W , Amemiya, Chris T , Dorrington, Rosemary A , Blatch, Gregory L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6466 , http://hdl.handle.net/10962/d1005795
- Description: The discovery of the African coelacanth in 1938 and subsequently the Indonesian coelacanth in 1998 has resulted in a keen interest in molecular studies on the coelacanth. A major focus has been on the phylogenetic position of the coelacanth. Lobe-finned fish such as the coelacanth are thought to be at the base of the evolutionary branch of fish leading to tetrapods. These studies have further aimed to resolve the phylogenetic relationship of extant lobe-finned fish (two coelacanth species and the lungfishes) to vertebrates. Notwithstanding the lack of readily accessible good-quality coelacanth tissue, several major contributions to coelacanth molecular studies and biology have been possible. The mitochondrial genome sequences of both species of the coelacanth suggest that they diverged from one another 40–30 million years ago. A number of large gene families such as the HOX, protocadherin and heat shock protein clusters have been characterized. Furthermore, the recent successful construction of a large-insert (150–200 kilobase) genomic library of the Indonesian coelacanth will prove to be an invaluable tool in both comparative and functional genomics. Here we summarize and evaluate the current status of molecular research, published and databased, for both the African (Latimeria chalumnae) and the Indonesian (Latimeria menadoensis) coelacanth.
- Full Text:
Isolation of genes encoding heat shock protein 70 (hsp70s) from the coelacanth, Latimeria chalumnae
- Modisakeng, Keoagile W, Dorrington, Rosemary A, Blatch, Gregory L
- Authors: Modisakeng, Keoagile W , Dorrington, Rosemary A , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6459 , http://hdl.handle.net/10962/d1005788
- Description: Under stress conditions, proteins unfold or misfold, leading to the formation of aggregates. Molecular chaperones can be defined as proteins that facilitate the correct folding of other proteins, so that they attain a stable tertiary structure. In addition, they promote the refolding and degradation of denatured proteins after cellular stress. Heat shock proteins form one of the main classes of molecular chaperones. We are interested in determining if the genome of the coelacanth (Latimeria chalumnae) encodes a heat shock protein-based cytoprotection mechanism. We have isolated 50 kb and larger coelacanth genomic DNA from frozen skin tissue of L. chalumnae. From the alignments of several fish Hsp70 proteins, conserved regions at the N- and C-termini were identified. Codon usage tables were constructed from published coelacanth genes and degenerate primers were designed to isolate the full-length hsp70 gene and regions encoding the ATPase and the peptide binding domains. Since it is known that the tilapia and Fugu inducible hsp70 genes are intronless, we proceeded on the assumption that a coelacanth inducible hsp70 would also be intronless. A large fragment (1840 bp) encoding most of a coelacanth Hsp70 protein, and two partial fragments encoding a coelacanth Hsp70ATPase domain (1048 bp) and peptide binding domain (873 bp), were isolated by polymerase chain reaction amplification. Protein sequences translated from all the nucleotide sequences were closely identical to typical Hsp70s. This is the first study to provide evidence for a cytoprotection mechanism in the coelacanth involving an inducible Hsp70.
- Full Text:
- Authors: Modisakeng, Keoagile W , Dorrington, Rosemary A , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6459 , http://hdl.handle.net/10962/d1005788
- Description: Under stress conditions, proteins unfold or misfold, leading to the formation of aggregates. Molecular chaperones can be defined as proteins that facilitate the correct folding of other proteins, so that they attain a stable tertiary structure. In addition, they promote the refolding and degradation of denatured proteins after cellular stress. Heat shock proteins form one of the main classes of molecular chaperones. We are interested in determining if the genome of the coelacanth (Latimeria chalumnae) encodes a heat shock protein-based cytoprotection mechanism. We have isolated 50 kb and larger coelacanth genomic DNA from frozen skin tissue of L. chalumnae. From the alignments of several fish Hsp70 proteins, conserved regions at the N- and C-termini were identified. Codon usage tables were constructed from published coelacanth genes and degenerate primers were designed to isolate the full-length hsp70 gene and regions encoding the ATPase and the peptide binding domains. Since it is known that the tilapia and Fugu inducible hsp70 genes are intronless, we proceeded on the assumption that a coelacanth inducible hsp70 would also be intronless. A large fragment (1840 bp) encoding most of a coelacanth Hsp70 protein, and two partial fragments encoding a coelacanth Hsp70ATPase domain (1048 bp) and peptide binding domain (873 bp), were isolated by polymerase chain reaction amplification. Protein sequences translated from all the nucleotide sequences were closely identical to typical Hsp70s. This is the first study to provide evidence for a cytoprotection mechanism in the coelacanth involving an inducible Hsp70.
- Full Text:
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