Structure of the human plasminogen activator inhibitor 1 gene: nonrandom distribution of introns.
Plasminogen activator inhibitor 1 (PAI-1) is the primary inhibitor of tissue-type plasminogen activator and thus performs an essential role in the regulation of the fibrinolytic process. It is a member of a large family of serine protease inhibitors (serpins). We determined the structure of the PAI-1 gene in order to more completely investigate the relationship of PAI-1 to other serpins and, at the same time, to begin to delineate structure-function relations in PAI-1 itself. A human genomic cosmid DNA library was screened and found to contain two independent clones, each harboring the entire PAI-1 gene. Restriction site mapping, electron microscopic inspection of heteroduplexes, and nucleotide sequence analysis all demonstrate that the PAI-1 gene is approximately 12.2 kilobase pairs in length and consists of nine exons and eight introns. All intron-exon boundaries are in accord with the "GT-AG" rule, including a cryptic acceptor splice site found in intron 7. The intron-exon pattern of the PAI-1 gene is distinct from that of most other serpins except that intron 3 of PAI-1 occupies an identical position as intron E of ovalbumin. Comparison of our data with the proposed subdomain structure of serpins suggests that seven of the eight introns may occupy a nonrandom position in the gene. These introns either delineate boundaries of individual structural subdomains or are located in random coil regions of the protein. Transcription of the PAI-1 gene in cultured vascular endothelial cells results in two distinct mRNA species. Our data suggest that these two transcripts arise by alternative polyadenylation.
Loskutoff
D J
DJ
Department of Molecular Biology, Free University of Amsterdam, The Netherlands.
Linders
M
M
Keijer
J
J
Veerman
H
H
van Heerikhuizen
H
H
Pannekoek
H
H
D001483:Base Sequence; D002874:Chromosome Mapping; D003360:Cosmids; D004247:DNA / Q000032:analysis / Q000302:isolation & purification; D004262:DNA Restriction Enzymes / Q000378:metabolism; D005796:Genes; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D015849:Plasminogen Inactivators; D011487:Protein Conformation
D006023:Glycoproteins; D015849:Plasminogen Inactivators; D004247:DNA; D004262:DNA Restriction Enzymes