Identification of a Novel Transcription Unit in the Human Insulin-like Growth Factor-II Gene
Overview
Affiliations
The human insulin-like growth factor-II (hIGF-II) gene has until now been thought to be composed of eight exons, including three independent leader exons. In the present study two additional exons, one leader exon and one alternatively used ordinate exon, have been newly identified. They were abundantly expressed in human histiocytoma tissue, generating mRNA species of about 5.0 kb in length. The new leader exon shows significant sequence similarity with the rE1 exon, previously reported to be transcribed only in the rat, and is mapped at nearly the same genomic location as in the rat. On the other hand, sequence similarity with another exon in the corresponding region of the rat genome was also found. It was, however, obvious that the rat sequence would not work as an active exon, since both splice acceptor and donor sites were deviated considerably from the consensus sequences. It has thus become apparent that the complex transcription unit of a single-copy hIGF-II gene comprises at least 10 exons, including four leader exons, one alternative exon and three common protein-coding exons.
Similarity and variation in the insulin-like growth factor 2 - H19 locus in primates.
Rotwein P Physiol Genomics. 2018; 50(6):425-439.
PMID: 29602297 PMC: 6032289. DOI: 10.1152/physiolgenomics.00030.2018.
The complex genetics of human insulin-like growth factor 2 are not reflected in public databases.
Rotwein P J Biol Chem. 2018; 293(12):4324-4333.
PMID: 29414792 PMC: 5868277. DOI: 10.1074/jbc.RA117.001573.
Zumkeller W Sarcoma. 2008; 2(2):69-76.
PMID: 18521237 PMC: 2395388. DOI: 10.1080/13577149878028.
IGF-II promoter methylation and ovarian cancer prognosis.
Beeghly A, Katsaros D, Wiley A, Rigault de la Longrais I, Prescott A, Chen H J Cancer Res Clin Oncol. 2007; 133(10):713-23.
PMID: 17569086 DOI: 10.1007/s00432-007-0211-3.
Transcriptional regulation and biological significance of the insulin like growth factor II gene.
Engstrom W, Shokrai A, Otte K, Granerus M, Gessbo A, Bierke P Cell Prolif. 1999; 31(5-6):173-89.
PMID: 9925986 PMC: 6647699. DOI: 10.1111/j.1365-2184.1998.tb01196.x.