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- Divergence of duplicate POMC genes in gilthead sea bream Sparus auratusPublication . Cardoso, João; Laiz-Carrión, R.; Louro, Bruno; Silva, Nádia; Canario, Adelino V. M.; Mancera, J. M.; Power, DeborahProopiomelanocorticotrophin (POMC) in vertebrates is produced in the pituitary gland and undergoes post-translational processing to give rise to a range of biologically active peptides. Teleosts possess 2–3 different POMC transcripts which have been proposed to have originated from a whole or partial genome duplication. In the present study 2 transcripts of gilthead sea bream POMC (sbPOMC-a1 and a2) were cloned and characterised. sbPOMC-a1 is expressed principally in the melanotroph cells of the pars intermedia (PI) and sbPOMC-a2 is expressed in the corticotroph cells of the rostral pars distalis and probably also in the PI. The 2 sbPOMC transcripts have a differential tissue distribution in extra-pituitary sites. An appraisal of POMC evolution indicates sbPOMCs belong to one of the two main clades that exist in teleosts and that overall a non conservative process of gene loss occurred in this infraclass.
- CRTAC1 homolog proteins are conserved from cyanobacteria to man and secreted by the teleost fish pituitary glandPublication . Redruello, Begoña; Louro, Bruno; Anjos, Liliana; Silva, Nádia; Greenwell, Roger S.; Canario, Adelino V. M.; Power, DeborahCartilage acidic protein 1 (CRTAC1) gene expression is used as a marker for chondrocyte differentiation instem cell-based tissue engineering. It is also transcribed outside the skeleton where at least two different transcripts are expressed in lung and brain. In the pituitary gland of the teleost fish sea bream Sparus auratus, we have found a transcript with a high degree of sequence identity to CRTAC1 family members but lacking the EGF-like calcium-binding domain encoding sequence of CRTAC1 and designated it as CRTAC2. Database searches revealed many previously unidentified members of the CRTAC1 and CRTAC2 in phylogenetically distant organisms, such as cyanobacteria, bryophyta, lancelets, and diverse representatives of vertebrates. Phylogenetic analyses showed that the genes encoding CRTAC1 and CRTAC2 proteins coexist in teleost fish genomes. Structural prediction analysis identified the N-terminal region of the CRTAC1/CRTAC2 family members as a potential seven-bladed β -propeller structure, closely related to those of integrin α chains and glycosylphosphatidylinositol-specific phospholipase D1 protein families. This relationship is con fi rmed by phylogenetic analysis with the N-terminal domain of sea bream CRTAC2 as the most divergent sequence. Because teleost fi shes are the only phylogenetic group where both CRTAC1 and CRTAC2 genes are present, they occupy a pivotal position in studies of the mechanisms governing the speci fi c expression patterns of each gene/protein subfamily. This will be essential to elucidate their respective biological roles.