Biological, immunological, and binding properties of recombinant mouse placental lactogen-I.
Mouse placental lactogen-I (mPL-I) cDNA was inserted into a eukaryotic expression vector and introduced into Chinese hamster ovary cells. Cell lines that secrete high concentrations of mPL-I were isolated, and this glycoprotein was purified from the cell culture-conditioned medium. Recombinant mPL-I (mPL-Ir) is very similar to placental mPL-I (mPL-Ip) in its recognition by polyclonal antisera raised against either mPL-Ip or mPL-Ir, in displacing [125I]iodo-mPL-II from binding sites on mouse liver microsomal membranes, and in stimulating the synthesis of alpha-lactalbumin in primary cultures of mouse mammary epithelial cells. Structural comparison of mPL-Ir and mPL-Ip by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that mPL-Ir comprises several proteins with mol wt ranging from 34.5-38K, while mPL-Ip consists of a similar set of proteins with mol wt ranging from 36.5-42K. Treatment of the two proteins with neuraminidase resulted in similar 2-4K decreases in mol wt. Treatment of mPL-Ip with peptide:N-glycosidase-F to remove asparagine-linked oligosaccharide chains resulted in the formation of 28K and 29K mol wt species, while treatment of mPL-Ir with the same enzyme yielded 28K and 28.5K mol wt products.
Colosi
P
P
Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208.
Ogren
L
L
Southard
J N
JN
Thordarson
G
G
Linzer
D I
DI
Talamantes
F
F
D000818:Animals; D001681:Biological Assay; D002460:Cell Line; D006224:Cricetinae; D004247:DNA / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004848:Epithelium / Q000378:metabolism; D007768:Lactalbumin / Q000096:biosynthesis; D046911:Macromolecular Substances; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008862:Microsomes, Liver / Q000378:metabolism; D008970:Molecular Weight; D010928:Placental Lactogen / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D011863:Radioimmunoassay; D011869:Radioligand Assay; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D014162:Transfection
D046911:Macromolecular Substances; D011994:Recombinant Proteins; D004247:DNA; D007768:Lactalbumin; D010928:Placental Lactogen