Expression and stability of insulin-like growth factor-I (IGF-I) mRNA splicing variants in the GH3 rat pituitary cell line.
We have employed Northern blot analyses and solution hybridization/RNase protection assays to evaluate the presence and stability of IGF-I mRNA splicing variants in the GH3 rat pituitary cell line. All of the IGF-I mRNA size classes and IGF-I mRNAs with alternately-spliced 5'-untranslated regions and E-peptide coding regions seen in adult rat liver also were present in GH3 cells, although the proportions of the 5' splicing variants were significantly altered. In actinomycin D-treated cells, all IGF-I mRNA splicing variants were equally stable; thus, changes in the levels of some splicing variants were not due to differential mRNA stability. Additionally, all IGF-I mRNA size classes seen on Northern blots were equally stable; this data suggests that the large IGF-I mRNA species is not a precursor of the smaller species.
Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
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Lowe
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Adamo
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LeRoith
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Roberts
D000199:Actins / Q000235:genetics; D000818:Animals; D015152:Blotting, Northern; D002460:Cell Line; D005786:Gene Expression Regulation / Q000187:drug effects; D013006:Growth Hormone / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D009004:Monosaccharide Transport Proteins / Q000235:genetics; D010902:Pituitary Gland / Q000502:physiology; D012326:RNA Splicing / Q000187:drug effects; D051381:Rats; D013002:Somatomedins / Q000235:genetics*
D000199:Actins; D009004:Monosaccharide Transport Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone