TY - JOUR
T1 - Transcription initiation in the two leader exons of the rat IGF-I gene occurs from disperse versus localized sites
AU - Adamo, Martin L.
AU - Ben-Hur, Haya
AU - Leroith, Derek
AU - Roberts, Charles T.
N1 - Funding Information:
Acknowledgments: MLA is the recipient of a post-doctoral fellowship from the Juvenile Diabetes Foundation. Ms. V. Katz is thanked for excellent secretarial assistance. This work was supported in part by a grant from the Diabetes Research and Education Foundation to C.T.R., Jr.
PY - 1991/4/30
Y1 - 1991/4/30
N2 - Rat IGF-I mRNAs contain two different 5′-UTR sequences as a result of alternate splicing of leader exons. Using a combination of solution hybridization/RNase protection and primer extension assays, we have mapped the transcriptional start sites in these leader exons. There appear to be three putative transcription start sites in exon I spread over a 140-bp region, the most upstream of which defines a 381 bp-long exon 1. There appear to be three distinct start sites in exon 2, the most upstream of which defines a greater than 770 bp-long exon 2. The two downstream start sites in exon 1 together account for ∼70% of IGF-I gene expression in adult rat liver. Essentially all of the remaining IGF-I gene expression comes from the second start site in exon 2. Rat IGF-I gene transcription may therefore be regulated by two distinct promoter regions, a disperse promoter for exon 1, with several transcription initiation sites, and a more typical promoter region for exon 2, which controls transcription initiation from a discrete region.
AB - Rat IGF-I mRNAs contain two different 5′-UTR sequences as a result of alternate splicing of leader exons. Using a combination of solution hybridization/RNase protection and primer extension assays, we have mapped the transcriptional start sites in these leader exons. There appear to be three putative transcription start sites in exon I spread over a 140-bp region, the most upstream of which defines a 381 bp-long exon 1. There appear to be three distinct start sites in exon 2, the most upstream of which defines a greater than 770 bp-long exon 2. The two downstream start sites in exon 1 together account for ∼70% of IGF-I gene expression in adult rat liver. Essentially all of the remaining IGF-I gene expression comes from the second start site in exon 2. Rat IGF-I gene transcription may therefore be regulated by two distinct promoter regions, a disperse promoter for exon 1, with several transcription initiation sites, and a more typical promoter region for exon 2, which controls transcription initiation from a discrete region.
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U2 - 10.1016/S0006-291X(05)80269-4
DO - 10.1016/S0006-291X(05)80269-4
M3 - Article
C2 - 2025299
AN - SCOPUS:0025872724
SN - 0006-291X
VL - 176
SP - 887
EP - 893
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 2
ER -