Promoter usage for insulin-like growth factor-II in cancerous and benign human breast, prostate, and bladder tissues, and confirmation of a 10th exon.
Upregulation of insulin-like growth factor (IGF)-II expression has been reported for a variety of childhood and adulthood tumors. We determined IGF-II gene promoter usage in human cancerous and benign tissues by semiquantitative RT-PCR using P1-P4-specific primers. Although the human IGF-II gene structure is commonly thought to consist of nine exons and four promoters, we detected substantial utilization of a previously reported exon 4b, which is downstream of exon 4. Thus, exon 4b was intensively studied using 4b-specific primers. IGF-II gene promoter usage is highly variable in malignant and benign breast, prostate, and bladder tissues. While a majority of samples utilized P2-P4 promoters in a variety of combinations, when quantitated, P3 and P4 promoters were much more active than P2 promoter. This study not only demonstrated that IGF-II gene promoter usage is highly variable in malignant and benign tissues, but suggested that alternatively spliced exon 4b should be recognized as a 10th exon.
Mineo
R
R
Department of Molecular Biology, Beckman Research Institute of the City of Hope, Duarte, California 91010, USA.
Fichera
E
E
Liang
S J
SJ
Fujita-Yamaguchi
Y
Y
D000328:Adult; D017398:Alternative Splicing; D001483:Base Sequence; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics; D002460:Cell Line; D002648:Child; D017931:DNA Primers / Q000235:genetics; D005091:Exons; D005260:Female; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D007438:Introns; D008297:Male; D009369:Neoplasms / Q000235:genetics*; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D011467:Prostate / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured; D001743:Urinary Bladder / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000235:genetics
D017931:DNA Primers; D007335:Insulin-Like Growth Factor II