Isolation and characterization of a novel human thioredoxin-like gene hTLP19 encoding a secretory protein.

A novel human gene, named as hTLP19, was isolated and characterized as secretory protein by combining bioinformatics tools with experiments. The hTLP19 encodes 172 amino acid residues with signal peptide in its N-terminal and a thioredoxin (Trx) domain that is homologous with some genes in Mus musculus, Xenopus laevis, etc. Moreover, the result from insulin reduction assay indicated that the hTLP19 protein has Trx enzymatic activity. By comparing full-length cDNA with human genomic DNA, the hTLP19 gene might have seven coding exons spanning 35 kb of genomic DNA on the human chromosome 1p32.3. Northern blot analysis showed that human hTLP19 is expressed widely in many tissues with 1.6 kb band and extra 1.2 kb band in placenta. Subcellular localization and immunoblotting assays indicated that hTLP19 might be secreted out of cell through trans-Golgi network (TGN).