Molecular isolation and characterisation of carp transforming growth factor beta 1 from activated leucocytes

The transforming growth factor (TGF beta) family of proteins are a set of p leiotropic secreted signalling molecules with unique and potent immunoregul atory properties. In this study the molecular cloning of carp TGF beta(1), is reported. A partial cDNA of the TGF beta protein was initially identifie d from a cDNA pool, obtained by subtracting the cDNAs from Con A-induced ca rp head kidney leucocytes from uninduced carp head kidney leucocyte cDNA. T he entire coding sequence was assembled by sequencing both ends of the cDNA clone by using an anchored PCR reaction. Sequence analysis revealed an ORF encoding a protein of 376 amino acids, containing the similar unique patte rn of conserved cysteines (seven out of nine) in the cysteine knot structur e which exists in all known TCTF beta proteins. Compared with other animal TCT beta s, the cDNA clone shows approximately 59-42, 40-38 and 37-36% amin o acid identity with TGF beta(1), TGF beta(3), and TGF beta(2) respectively . Carp TGF beta(1) is expressed at low levels in carp head kidney, spleen, egg and liver, whereas its messenger RNA level is increased after activatio n of the head kidney leucocytes with Con A. Sequence analysis and pattern o f expression suggests that this is the carp TGF beta(1). (C) 2000 Academic Press.