Thromb Haemost 2000; 84(03): 468-473
DOI: 10.1055/s-0037-1614046
Commentary
Schattauer GmbH

The Molecular Basis for the Aberrant Production of Plasminogen Activator Inhibitor Type 2 in THP-1 Monocytes

Jackie Katsikis
1   From the Monash University Department of Medicine, Box Hill Hospital, Box Hill, Victoria, Australia
,
Hong Yu
1   From the Monash University Department of Medicine, Box Hill Hospital, Box Hill, Victoria, Australia
,
Fabienne Maurer
1   From the Monash University Department of Medicine, Box Hill Hospital, Box Hill, Victoria, Australia
,
Robert Medcalf
1   From the Monash University Department of Medicine, Box Hill Hospital, Box Hill, Victoria, Australia
› Author Affiliations

This work was supported by grants obtained by R.L.M from the National Health and Medical Research Council of Australia.
Further Information

Publication History

Received 03 January 2000

Accepted after revision 14 April 2000

Publication Date:
14 December 2017 (online)

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Summary

Plasminogen activator inhibitor type 2 (PAI-2) is a urokinase inhibitor that is expressed primarily in monocytes. THP-1 monocytes, however, contain a unique defect in the production of PAI-2 in that the PAI-2 transcript is truncated and the expressed protein inactive (1). Here we describe the basis of this mutation in THP-1 cells. Southern blot analysis of THP-1-derived genomic DNA indicated that there were no obvious deletions in the structure of the PAI-2 gene. However, assessment of the THP-1-derived PAI-2 transcript by RT-PCR indicated that only exons seven and eight of the normal PAI-2 mRNA could be detected. Cloning of the 5’ region of the PAI-2 mRNA by 5-’RACE indicated that the PAI-2 cDNA derived from THP-1 cells is approximately 1329 bp long and contains 180 bp of sequence derived from intron 5, followed by sequences corresponding to exons seven and eight of the normal PAI-2 mRNA. The presence of the intron five fragment in endogenous THP-1 derived PAI-2 mRNA was confirmed by Northern blotting. The absence of any wild-type PAI-2 mRNA in these cells suggests that one copy of the PAI-2 allele has been deleted. The remaining allele producing the truncated mRNA appears to have undergone a translocation event and contains a mutation that has disrupted the splicing of the PAI-2 primary transcript.