Cloning of leukemia inhibitory factor (LIF) and its expression in the uterus during embryonic diapause and implantation in the mink (Mustela vision)

摘要

A cDNA consisting of 758 nucleotides was isolated which comprised a 609-bp open reading frame for mink leukaemia inhibitory factor (LIF) encoding a deduced protein of 203 amino acids. The mink LIF showed 80.6, 90, 88.2, 87.6 and 86.8% homology in the coding sequence and 79.2, 90.1, 91, 90.1 and 85.4% homology in the amino acid sequence with mouse, human, pig, cow and sheep LIF respectively. In general, glycosylation sites and disulphide bonds present in other species were conserved in the mink LIFsequence. PCR amplification indicated that LIF mRNA was expressed in the mink uterus just before implantation and during the first 2 days after implantation, but not during diapause or after implantation. LIF mRNA was higher in the uterus at the embryo expansion stage than 1-2 days after implantation (P<0.05). Immunohistochemical localization showed that LIF was expressed in the uterine epithelial glands at the time of embryonic expansion and during early implantation. The results indicate that LIF is involved in the implantation process.