cDNA cloning, characterization, expression and recombinant protein production of leukemia inhibitory factor (LIF) from the marsupial, the brushtail possum (Trichosurus vulpecula)

A reverse transcription technique using RNA, templates combined with polyme rase chain reaction (RT-PCR) was used to clone the cDNA fragment encoding t he amino acid sequence of mature LIF protein of the marsupial, the brushtai l possum, Trichosurus vulpecula. A PCR product with expected size, of 546 b p, and termed tvLIF, was obtained using cDNA reverse-transcribed from total RNA isolated from possum uterus. A genomic DNA fragment (about 650 bp) bet ween the specified primers was also amplified, indicating the similarity in structure and organization of this gene and LIF genes from studied eutheri an species, although the full-length of its cDNA and genomic DNA needs to b e further clarified. The deduced amino acid sequence of tvLIF shows a high level of sequence identity and similar molecular characteristics to eutheri an LIF, which suggests similar biological actions of this molecule in this marsupial. Because the expression of LIF gene in other mammalian species ha s been found to be at very low levels and its transcripts cannot be detecte d by Northern hybridization analysis, the expression pattern of tvLIF in ad ult tissues and reproductive tracts during early development was investigat ed using the RT-PCR technique. Resultant products of the RT-PCR were furthe r analyzed by Southern hybridization using tvLIF as a probe, tvLIF transcri pts were detected in most of the adult tissues and in the reproductive trac ts of pregnant females. These results lend support to the idea that LIF con tributes to the maintenance of pregnancy in this marsupial. (C) 2000 Elsevi er Science B.V. All rights reserved.