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Identification and expression of an atypical isoform of metallothionein in the African clawed frog Xenopus laevis
- Source :
- Comptes Rendus Biologies. 338:314-320
- Publication Year :
- 2015
- Publisher :
- Elsevier BV, 2015.
-
Abstract
- Exploiting the annotation of the western clawed frog Silurana tropicalis genome, we identified a new metallothionein (MT) gene, exhibiting all the features to be considered an active gene, but with an atypical coding region, showing only 17 cysteine residues instead of the canonical 20 cysteines of vertebrate metallothioneins and two anomalous cysteine triplets. However, the presence of a gene in the genome does not ensure its effective expression. By using conventional and Real-Time PCR analyses, we demonstrated that this atypical MT is constitutively expressed throughout the life cycle of the African clawed frog Xenopus laevis; moreover, this gene is highly expressed in the adult liver, the major site of MT expression and synthesis in vertebrates. To our knowledge, the X. laevis MT described in this paper is the first sequence of a vertebrate MT showing only 17 cysteine residues, arranged in two Cys–Cys–Cys motifs. Phylogenetic analyses also demonstrated that the atypical X. laevis MT merges in the anuran clade, but is the most derived sequence among tetrapods MTs. Finally, Tajima's Relative Rate Test suggested a different evolutionary rate between the canonical X. laevis MT and this novel isoform.
- Subjects :
- Gene isoform
Aging
African clawed frog
DNA, Complementary
Molecular Sequence Data
Xenopus laevi
Xenopus
Real-Time Polymerase Chain Reaction
Real Time
General Biochemistry, Genetics and Molecular Biology
Xenopus laevis
Animals
Protein Isoforms
Coding region
Metallothionein
Amino Acid Sequence
Cysteine
Cloning, Molecular
Gene
Western clawed frog
Phylogeny
Silurana
Genetics
Base Sequence
General Immunology and Microbiology
biology
Computational Biology
General Medicine
biology.organism_classification
Biological Evolution
Molecular biology
Gene Expression Regulation
RNA
Gene expression
General Agricultural and Biological Sciences
Subjects
Details
- ISSN :
- 16310691
- Volume :
- 338
- Database :
- OpenAIRE
- Journal :
- Comptes Rendus Biologies
- Accession number :
- edsair.doi.dedup.....4d8874e782863e9ea6abaca2d7f08542