Isolation and characterization of a cDNA encoding the low molecular weight insulin-like growth factor binding protein (IBP-1).
IGF-I and IGF-II are growth-stimulating peptides with strong mitogenic properties. These polypeptide growth factors circulate in serum bound to specific binding proteins. We report the cloning and complete sequence of a cDNA encoding a low mol. wt IGF-binding protein from a human placenta cDNA library. We propose the designation IGF-binding protein 1 (IBP-1) for the gene and corresponding protein. Expression of the cDNA encoding IBP-1 in COS cells resulted in the synthesis of a 30-kd protein which binds IGF-I and is immunologically indistinguishable from the IGF-binding protein isolated from amniotic fluid or human serum. Northern blotting analysis demonstrated that expression of the IBP-1 gene is highly tissue specific and limited to placental membranes and fetal liver suggesting a rigid control. The IBP-1 gene is a single copy gene, located on chromosome 7. The results obtained suggest that most, if not all, lower mol. wt IGF-binding proteins originate from this gene.
Brinkman
A
A
Department of Pediatrics, Erasmus University/Sophia Childrens Hospital, Rotterdam, The Netherlands.
Groffen
C
C
Kortleve
D J
DJ
Geurts van Kessel
A
A
Drop
S L
SL
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D002460:Cell Line; D002874:Chromosome Mapping; D002897:Chromosomes, Human, Pair 7; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D004262:DNA Restriction Enzymes; D005786:Gene Expression Regulation; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010920:Placenta / Q000378:metabolism; D011233:Precipitin Tests; D011498:Protein Precursors / Q000096:biosynthesis / Q000235:genetics; D021382:Protein Sorting Signals / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D013002:Somatomedins / Q000378:metabolism*; D014162:Transfection
D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D013002:Somatomedins; D004247:DNA; D004262:DNA Restriction Enzymes