Isolation of an insulin-like growth factor II cDNA with a unique 5' untranslated region from human placenta.
Human insulin-like growth factor II (IGF-II) cDNA from a placental library was isolated and sequenced. The 5' untranslated region (5'-UTR) sequence of this cDNA differs completely from that of adult human liver and has considerable base sequence identity to the same region of an IGF-II cDNA of a rat liver cell line, BRL-3A. Human placental poly(A)+ RNA was probed with either the 5'-UTR of the isolated human placental IGF-II cDNA or the 5'-UTR of the IGF-II cDNA obtained from adult human liver. No transcripts were detected by using the 5'-UTR of the adult liver IGF-II as the probe. In contrast, three transcripts of 6.0, 3.2, and 2.2 kilobases were detected by using the 5'-UTR of the placental IGF-II cDNA as the probe or the probe from the coding sequence. A fourth IGF-II transcript of 4.9 kilobases presumably containing a 5'-UTR consisting of a base sequence dissimilar to that of either IGF-II 5'-UTR was apparent. Therefore, IGF-II transcripts detected may be products of alternative splicing as their 5'-UTR sequence is contained within the human IGF-II gene or they may be a consequence of alternative promoter utilization in placenta.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000302:isolation & purification*; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D008099:Liver / Q000032:analysis; D008969:Molecular Sequence Data; D010920:Placenta / Q000032:analysis*; D011061:Poly A / Q000032:analysis; D014176:Protein Biosynthesis; D012313:RNA / Q000032:analysis; D012333:RNA, Messenger; D051381:Rats; D013002:Somatomedins / Q000235:genetics*
D012333:RNA, Messenger; D013002:Somatomedins; D011061:Poly A; D012313:RNA; D007335:Insulin-Like Growth Factor II; D004247:DNA