cDNA Cloning, Prokaryotic and Eukaryotic Expression and Characterization of Porcine Leukemia Inhibitory Factor1

Molecular cloning of the porcine leukemia inhibitor factor (pLIF) has not been reported. A full-length cDNA encoding pLIF was cloned, expressed and characterized. The full-length porcine LIF cDNA encodes a 202 amino acid protein that has an 84% sequence identity to mouse LIF and 86% sequence identity to human LIF. The deduced amino acid sequence of a pLIF protein contains six conserved consensus N-linked glycosylation sites and six cysteine groups to form potential disulfide bonds. The pLIF was expressed in E coli, as a mature form, and in CHO cells as a secreted form. Both the forms of the recombinant pLIFs can maintain murine embryonic stem cells in an undifferentiated state in a culture. The recombinant pLIFs will be useful in establishing a long-term culture of stable pluripotent porcine embryonic stem cells for further manipulation.