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The aim of the study was to use Pichia pastoris to express a recombinant porcine lipase gene (pLip). The expression-secretion cassette was constructed using the P. pastoris GAPDH (glyceraldehyde-3-phosphate-dehydrogenase) promoter and an 89-residue prepro-alpha-factor secretion signal fused to the AOX1 terminator (the pGAPZalphaA vector). A total of 1,408 bp of pancreatic lipase cDNA was produced, which was located from the position of 4-nt upstream of ATG to 1408-nt inside the intact coding region of the pLip sequence. In an animal trial, three concentrations of recombinant lipase activity (0, 5,000 and 10,000 U/kg) were blended with the basal diet and fed to weaned piglets for six weeks. During the experimental period, the growth performance (bodyweight, feed intake, and feed efficiency) of the test groups was superior to that of the control group (p < 0.05). Furthermore, the group fed the diet blended with 10,000 U/kg of recombinant lipase showed significant (p < 0.05) increases in blood triglyceride (TG) concentration on the seventh day postweaning. These results suggested that the porcine lipase protein yielded by transformed yeast cells may improve fat digestibility and enhance the growth performance in postweaning piglets.

Ribosomal RNA large subunit methyltransferase J (RrmJ), an Escherichia coli heat shock protein, is responsible for 2′-O-ribose methylation in 23S rRNA. In mammals, three close homologs of RrmJ have been identified and have been designated as FTSJ1, FTSJ2 and FTSJ3; however, little is known about these genes. In this study, we characterized the mammalian FTSJ2, which was the most related protein to RrmJ in a phylogenetic analysis that had similar amino acid sequence features and tertiary protein structures of RrmJ. FTSJ2 was first identified in this study as a nucleus encoded mitochondrial protein that preserves the heat shock protein character in mammals in which the mRNA expressions was increased in porcine lung tissues and A549 cells after heat shock treatment. In addition, a recent study in non-small cell lung cancer (NSCLC) suggested that the FTSJ2 gene is located in a novel oncogenic locus. However, our results demonstrate that the expression of FTSJ2 mRNA was decreased in the more invasive subline (CL1-5) of the lung adenocarcinoma cells (CL1) compared with the less invasive subline (CL1-0), and overexpression of FTSJ2 resulted in the inhibition of cell invasion and migration in the rhabdomyosarcoma cell (TE671). In conclusion, our findings indicate that mammalian FTSJ2 is a mitochondrial ortholog of E. coli RrmJ and conserves the heat shock protein properties. Moreover, FTSJ2 possesses suppressive effects on the invasion and migration of cancer cells.