Plasminogen activator inhibitor type 2 contains mRNA instability elements within exon 4 of the coding region. Sequence homology to coding region instability determinants in other mRNAs.
Plasminogen activator inhibitor type 2 (PAI-2) is a serine protease inhibitor that inhibits urokinase. Constitutive and regulated PAI-2 gene expression involves post-transcriptional events, and an AU-rich mRNA instability motif within the 3'-untranslated region of PAI-2 mRNA is required for this process (Maurer, F., Tierney, M., and Medcalf, R. L. (1999) Nucleic Acids Res. 27, 1664-1673). Here we show that instability determinants are present within various exons of the PAI-2 coding region, most notably within exon 4. Deletion of exon 4 from the full-length PAI-2 cDNA results in a doubling in the half-life of PAI-2 mRNA, whereas a 28-nucleotide region within exon 4 contains binding sites for cytoplasmic proteins. Inducible stabilization of PAI-2 mRNA in HT-1080 cells treated with phorbol ester and tumor necrosis factor does not alter the binding of proteins to the exon 4 instability determinant, but resulted in a transient increase in the binding of factors to the AU-rich RNA instability element. Hence, PAI-2 mRNA stability is influenced by elements located within both the coding region and the 3'-untranslated region and that cytoplasmic mRNA binding factors may influence steady state and inducible PAI-2 mRNA expression. Finally a 10-nucleotide region flanking the exon 4 protein-binding site is homologous to instability elements within five other transcripts, suggesting that a common coding region determinant may exist.
Department of Medicine, Monash University, Box Hill Hospital, Box Hill 3128, Victoria, Australia.
M J
MJ
Tierney
R L
RL
Medcalf
D020413:3' Untranslated Regions / Q000378:metabolism; D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015152:Blotting, Northern; D015153:Blotting, Western; D002273:Carcinogens; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D016373:DNA, Antisense / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005091:Exons; D017353:Gene Deletion; D017930:Genes, Reporter; D019382:Human Growth Hormone / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010703:Phorbol Esters; D010957:Plasmids / Q000378:metabolism; D017396:Plasminogen Activator Inhibitor 2 / Q000737:chemistry* / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000187:drug effects; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014466:Ultraviolet Rays
D020413:3' Untranslated Regions; D002273:Carcinogens; D016373:DNA, Antisense; D018076:DNA, Complementary; D010703:Phorbol Esters; D017396:Plasminogen Activator Inhibitor 2; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D019382:Human Growth Hormone