Human plasminogen activator inhibitor-1 gene. Promoter and structural gene nucleotide sequences

Automated DNA sequencing of the human HPRT locus

The complete sequence of 57 kb of the human HPRT locus has been determined using automated fluorescent DNA sequencing. The strategy employed increasingly directed sequencing methods: A randomly generated M13 library was sequenced to generate contiguous overlapping sets of sequences (contigs). M13 clones at the ends of these contigs were further sequenced using M13 (universal and reverse) and custom oligonucleotide primers to order the contigs and to complete the sequencing project. The human HPRT sequence includes 1676 bp 5' and 15,238 bp 3' to exons 1 and 9, respectively. The sequence contains 49 representatives of the Alu repeat, along with several other types of repetitive sequences. The Alu sequences exhibit a biased orientation, with those sequences in the first half of the locus oriented in the minus direction relative to transcription of the gene (3'----5' = 77%, P less than 0.005) and those sequences in the latter half of the locus oriented randomly (5'----3' = 67%, P less than 0.5). The development and performance of the sequencing strategy and the features of the human HPRT gene are presented.

Chromosomal organization and localization of the human urokinase inhibitor gene: perfect structural conservation with ovalbumin

Plasminogen activator inhibitor 2 (PAI-2) plays an essential role in the regulation of localized extracellular proteolysis by its inactivation of urokinase. Using probes derived from a cDNA we isolated from lipopolysaccharide (LPS)-stimulated human peripheral blood monocytes, we have mapped, isolated, and determined the molecular organization of the gene for PAI-2 (PLANH2). In situ hybridization of the cDNA to normal metaphase chromosomes has confirmed our prior assignment of the gene for PAI-2 to chromosome 18 and further localized it to the long arm at 18q21.2-18q22. We have isolated nine independent genomic clones, two of which were found to contain the entire PAI-2 transcriptional unit of approximately 16.4 kilobase pairs (kbp). Analysis of the gene organization by restriction enzyme mapping, Southern blotting, and DNA sequencing revealed that the cDNA sequence is divided among eight exons interrupted by seven introns, the junctions of which all conform to the "GT-AG" consensus rule. In common with the arrangement found throughout, the serpin superfamily, of which PAI-2 is a member, the first intron is located just 5' to the initiator methionine residue, and the 3' untranslated region (UTR) is not interrupted by a splice junction. Determination of the transcription initiation site by primer extension analysis of monocytic mRNA indicated that our PAI-2 cDNA was, at most, only three nucleotides short of full length, yielding a primary PAI-2 transcript with a 66-bp first exon. A promoter "TATAAAbox" is located 30 bp upstream of the "cap" site.(ABSTRACT TRUNCATED AT 250 WORDS)

The 5' flanking region and chromosomal localization of the gene encoding human platelet membrane glycoprotein Ib alpha

The human blood platelet membrane glycoprotein Ib (GPIb) functions as a receptor for von Willebrand factor and thrombin. The gene (gpIb alpha) encoding the GPIb alpha-chain was cloned from a genomic cosmid library. The promoter region of this gene was characterized by sequencing two BamHI fragments including 2.8 kb of the 5' flanking region where several Alu repeated elements and purine-rich sequences were found. Possible cis-regulatory elements were identified by comparing the gpIb alpha gene with established consensus sequences known to function as binding sites for transcription factors. To obtain further information on possible megakaryocyte-specific promoter or enhancer sequences, the gpIb alpha promoter region was compared with other genes expressed in platelets that are known so far. The gpIb alpha gene was found to be located on chromosome 17 in region 17p12-ter, by in situ hybridization.

Structure and expression of the human gene encoding plasminogen activator inhibitor, PAI-1

The gene (pai1) encoding human plasminogen activator inhibitor, PAI-1 was cloned from a lambda EMBL3 genomic library and was found to span approx. 12 kb and to contain eight introns. Primer extension and S1 nuclease analyses both showed the transcription start point to be located 142 nt upstream from the start codon. The 5'-flanking region was sequenced and found to contain a TATA box, but no CAAT sequence. When a fragment containing 730 nt of 5'-untranslated region was placed upstream from a promoterless cat gene, it was shown to function as a promoter when transfected into COS cells. Northern-blot analysis was consistent with low level expression of the endogenous pai1 gene in COS cells. When the pai1 gene structure was compared to those of other members of the serine-protease-inhibitor encoding gene family, little conservation of intron positions was observed.

Determination of exon-intron structure: a novel application of the polymerase chain reaction technique

We describe a novel application of the polymerase chain reaction (PCR) technique of DNA amplification to study the exon-intron structure of the rat plasminogen activator inhibitor (PAI-1) gene. This technique is relatively simple and also allows the isolation of introns for sequencing. Primers were selected based on a knowledge of the cDNA sequences of human and rat PAI-1 and of the gene structure of human PAI-1. However, knowledge of a cDNA sequence and/or the structure of a gene in another species is not a prerequisite. Sequences selected from positions along the cDNA of interest could be used to amplify the DNA either from an isolated but uncharacterized gene or directly from genomic DNA, making this technique generally applicable. Thus, this method is a useful advance in the study of gene structure and evolution.

von Willebrand factor and platelet function

vWF is an adhesive protein that binds to two distinct platelet glycoproteins, GP Ib and GP IIb-IIa complex. Its interaction with GP Ib is primarily responsible for platelet adhesion to the subendothelium. The current model is that vWF binds to collagen and/or another component of the subendothelium, after which a conformational change in the vWF molecule exposes the GP Ib binding site. This interaction may not only promote the initial attachment of platelets to the subendothelium but also play a role in thrombus formation through exposure of GP IIb-IIIa to which vWF and fibrinogen can bind. The second important function of vWF is to be a carrier for F. VIII, protecting it from degradation and playing a role in its activation by thrombin. Circulating vWF has a complex multimeric structure that ranges in Mrs from 0.5 to 20 x 10(6) Daltons. The basic subunit has a Mr of 270 kDa. Amino acid sequencing of vWF demonstrated that the basic subunit or mature vWF is made up of 2050 amino acids. Molecular cloning of the vWF cDNA revealed that the primary transcript consists of 8900 base pairs that encode for 2813 amino acids, including a 22 amino acid signal peptide and a propolypeptide of 741 amino acids, called vWF antigen II. Recent studies on the expression of recombinant vWF molecules indicate that the propolypeptide is involved in the multimerization of vWF. The domains on the vWF molecule involved in the interactions of vWF with GP Ib, GP IIb-IIIa, collagen, F. VIII and heparin have been localized to varying extents. It is anticipated that peptide analysis and recombinant DNA techniques, such as in vitro mutagenesis, will further define the structural requirements of these binding domains. vWF is synthesized in a cell-specific manner by endothelial cells and megakaryocytes. It undergoes a complex intracellular biosynthesis involving transcription of a 200 kb gene, splicing out more than 42 introns, translation of a 8900 bp mRNA, glycosylation, disulphide bond formation, sulphatation, multimerization and proteolytic cleavage. The molecule can be secreted in a constitutive or regulated manner upon perturbation of the endothelial cells with physiological and non-physiological secretagogues. The mechanisms that control the synthesis of vWF should be an exciting area of further research. vWD is probably the most common of all congenital disorders of haemostasis. It is an extremely heterogeneous syndrome involving quantitative or qualitative disorders of vWF.(ABSTRACT TRUNCATED AT 400 WORDS)

Complete sequence of the human tissue factor gene, a highly regulated cellular receptor that initiates the coagulation protease cascade

Tissue factor (TF) is the high-affinity receptor for plasma factors VII and VIIa. TF plays a role in normal hemostasis by initiating the cell-surface assembly and propagation of the coagulation protease cascade. Outside the vasculature, TF expression is highly dependent upon cell type. TF can also be induced by inflammatory mediators to appear on monocytes and vascular endothelial cells as a component of cellular immune responses. As an initial step toward elucidating the regulatory regions involved in control of TF gene expression, we have established the organization of the 12.4 kbp human TF gene and its complete DNA sequence. There are six exons separated by five introns. Within intron 5, we have mapped the single nucleotide difference which leads to the previously described MspI polymorphism; the same intron also contains an apparently polymorphic PstI site. The TF gene also contains three full-length Alu repeats and one partial Alu repeat. A single major transcription start site was identified 26 bp downstream from a TATA consensus promoter element. The putative promoter and first exon are located within a 1.2 kbp region of very high G + C content which fits the criteria of an HTF island. A cluster of predicted binding sites for a number of known transcription factors was found to coincide with this putative promoter region. These factors included AP-1 and AP-2 which can mediate the effects of phorbol esters, agonists known to induce TF expression in monocytes and vascular endothelial cells.

Cloning and sequencing of cDNA for the rat plasminogen activator inhibitor-1

A cDNA encoding rat plasminogen activator-inhibitor (PAI-1) has been isolated from an HTC rat hepatoma cell cDNA library constructed in phage lambda gt10. The cDNA contains 118 bp of 5'-untranslated sequence, 1206 bp encoding a 402-amino acid (aa) protein and 1747 bp of 3'-untranslated sequence. The protein-coding sequence and the derived amino acid sequence share 82% and 81% identity, respectively, with human PAI-1 cDNA and protein. The rat cDNA encodes a preprotein with a 23-aa leader peptide and a predicted N-terminal serine for the mature protein. Three of four potential N-glycosylation acceptor sites as well as the active site of rat PAI-1 are identical to the human protein. The 3'-untranslated region contains a number of unusual regions, including 80 bp of tandemly repeated GpA dinucleotides, a 115-bp stretch which shares greater than 90% sequence identity with a region within the 3'-untranslated cDNA of human PAI-1, and two 70-bp stretches of highly T-rich sequence located close to the 3'-terminus of the cDNA.