Cloning and sequencing hybrid striped bass (Morone saxatilis x M. chrysops) transforming growth factor-β (TGF-β), and development of a reverse transcription quantitative competitive polymerase chain reaction (RT-qcPCR) assay to measure TGF-β mRNA of teleost fish

A transforming growth factor (TGF)-β was isolated and cloned from hybrid striped bass (Morone saxatilis x M. chrysops) anterior kidney mononuclear cells. This isolate (Genbank accession number AF140363) contains an open reading frame of 1146 bases coding for a 382 amino acid protein most similar to rainbow trout TGF-β (57·3 and 78·6% identity with precursor and active protein, respectively) and rat TGF-β1(41·1 and 68·8% identity with precursor and active protein, respectively). Consensus primers were demonstrated to amplify specifically by polymerase chain reaction (PCR), a TGF-β segment from 14 species of teleost fish comprising 10 taxonomic families in 7 orders. A reverse transcription quantitative competitive polymerase chain reaction (RT-qcPCR) assay was devised to measure TGF-β mRNA expression in teleost fish. Higher levels of TGF-β mRNA expression were detected in mononuclear cells of peripheral blood than from spleen or anterior kidney.