Reference : The zebrafish genome encodes the largest vertebrate repertoire of functional aquapori...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/109496
The zebrafish genome encodes the largest vertebrate repertoire of functional aquaporins with dual paralogy and substrate specificities similar to mammals
English
[en] The zebrafish genome encodes the largest vertebrate repertoire of functional aquaporins with dual paralogy and substrate specificities similar to mammals
Tingaud-Sequeira, Angèle [ > > ]
Calusinska, Magdalena mailto [Université de Liège - ULg > > Centre d'ingénierie des protéines >]
Finn, Roderick N [ > > ]
Chauvigné, François [ > > ]
Lozano [ > > ]
Cerdà, Joan [ > > ]
2010
BMC Evolutionary Biology
BioMed Central
10
Yes (verified by ORBi)
International
1471-2148
[en] zebrafish ; aquaporins
[en] Background: Aquaporins are integral membrane proteins that facilitate the transport of water and small solutes
across cell membranes. These proteins are vital for maintaining water homeostasis in living organisms. In mammals,
thirteen aquaporins (AQP0-12) have been characterized, but in lower vertebrates, such as fish, the diversity,
structure and substrate specificity of these membrane channel proteins are largely unknown.
Results: The screening and isolation of transcripts from the zebrafish (Danio rerio) genome revealed eighteen
sequences structurally related to the four subfamilies of tetrapod aquaporins, i.e., aquaporins (AQP0, -1 and -4),
water and glycerol transporters or aquaglyceroporins (Glps; AQP3 and AQP7-10), a water and urea transporter
(AQP8), and two unorthodox aquaporins (AQP11 and -12). Phylogenetic analyses of nucleotide and deduced amino
acid sequences demonstrated dual paralogy between teleost and human aquaporins. Three of the duplicated
zebrafish isoforms have unlinked loci, two have linked loci, while DrAqp8 was found in triplicate across two
chromosomes. Genomic sequencing, structural analysis, and maximum likelihood reconstruction, further revealed
the presence of a putative pseudogene that displays hybrid exons similar to tetrapod AQP5 and -1. Ectopic
expression of the cloned transcripts in Xenopus laevis oocytes demonstrated that zebrafish aquaporins and Glps
transport water or water, glycerol and urea, respectively, whereas DrAqp11b and -12 were not functional in
oocytes. Contrary to humans and some rodents, intrachromosomal duplicates of zebrafish AQP8 were water and
urea permeable, while the genomic duplicate only transported water. All aquaporin transcripts were expressed in
adult tissues and found to have divergent expression patterns. In some tissues, however, redundant expression of
transcripts encoding two duplicated paralogs seems to occur.
Conclusion: The zebrafish genome encodes the largest repertoire of functional vertebrate aquaporins with dual
paralogy to human isoforms. Our data reveal an early and specific diversification of these integral membrane
proteins at the root of the crown-clade of Teleostei. Despite the increase in gene copy number, zebrafish
aquaporins mostly retain the substrate specificity characteristic of the tetrapod counterparts. Based upon the
integration of phylogenetic, genomic and functional data we propose a new classification for the piscine
aquaporin superfamily.
Researchers
http://hdl.handle.net/2268/109496

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