Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Cloning, characterisation and tissue distribution of an aquaporin-3 cDNA from fish (Sparus aurata)Publication . Santos, CRA; Fuentes, Juan; Cardoso, João CR; Estêvão, Dulce; Power, DeborahThe major intrinsic protein (MIP) family consists of several transmembrane channel proteins specific for water and neutral solutes. All proteins belonging to the MIP family evolved from two divergent bacterial paralogues, one giving rise to the CHIP group, functionally characterised as water channels and the other to the GLP group, specialised in glycerol transport. Three forms of MIP proteins belonging to the GLP group have been identified in mammals: aquaporin-3 (AQP-3), aquaporin-7 (AQP-7) and aquaporin-9 (AQP-9). We have recently cloned and characterised a GLP cDNA from the marine teleost sea bream (Sparus aurata) and studied its tissue distribution. Phylogenetic analysis revealed it was most like AQP-3 and further studies are now underway to determine its role in hydromineral balance.
- Identification of transthyretin in fish (Sparus aurata): cDNA cloning and characterisationPublication . Santos, CRA; Power, DMTransthyretin (TTR) has been proposed to have first evolved in reptiles and is one of the three plasma proteins important in the transport of thyroid hormones in higher vertebrates. A full-length cDNA encoding TTR was isolated from a sea bream (Sparus aurata) liver cDNA library using a homologous TTR cDNA probe generated by RT-PCR. Comparison of the deduced amino acid sequence of sea bream TTR with other published sequences, revealed an overall identity of 47-54%, although the amino acids in the active binding site were almost 100% conserved. Distribution of TTR was studied in sea bream adult tissue by RT-PCR and was detected in liver, brain, pituitary, gills, kidney, intestine and testis although northern blot analysis only revealed TTR in the liver, suggesting that in sea bream, liver is the main source of this protein. TTR was also expressed in larvae from the first day post-hatch (48h post-fertilisation), Analysis of thyroxine (T-4) and triiodo-L-thyronine (T-3) binding to sea bream serum proteins demonstrated that both T-4 and T-3 bind to albumin and TTR. By demonstrating the existence of TTR in teleost fish this study indicates TTR must have evolved in a common fish ancestor of the tetrapod evolutionary line.