Characterization and targeting of the murine alpha2-antiplasmin gene.
Alpha2-Antiplasmin (alpha2-AP) is the main physiological plasmin inhibitor in mammalian plasma. As a first step toward the generation of alpha2-AP deficient mice, the murine alpha2-AP gene was characterized and a targeting vector for homologous recombination in embryonic stem (ES) cells constructed. Alignment of nucleotide sequences obtained from genomic subclones allowed location of exons 2 through 10 of the alpha2-AP gene, but failed to identify the 5' boundary of exon 1. Compared to the human gene, exons 2 through 9 in the murine gene have identical size and intron-exon boundaries obeying the GT/AG rule. The 5' boundary of exon 10 is identical in both genes while the 3' non-coding region is 64 bp longer in the human gene. Introns 2, 3, 6 and 8 have similar sizes in the mouse and human genes; intron 1 is 6-fold smaller, introns 5, 7 and 9 are 2- to 3-fold smaller, whereas intron 4 is about 2-fold larger in the mouse gene. Compared to the human 5' flanking sequence, an insertion of a simple repeat region with sequence (TGG)n has occurred. The open reading frame of the mouse alpha2-AP gene encodes a 491-amino-acid protein comprising the experimentally determined NH2-terminus of the mature protein Val-Asp-Leu-Pro-Gly-. A targeting vector, pPNT.alpha2-AP, was constructed by introducing a homologous sequence of 8.3 kb in total in the parental pPNT vector. In pPNT.alpha2-AP, the neomycin resistance expression cassette replaces a 7 kb genomic fragment comprising exon 2 through part of exon 10 (including the stop codon), which represents the entire sequence encoding the mature protein, including the fibrin-binding domain, the reactive site peptide bond and the plasmin(ogen)-binding region. Electroporation of 129R1 embryonic stem (ES) cells with the linearized vector pPNT.alpha2-AP yielded three targeted clones with correct homologous recombination at the 5'- and 3'-ends, as confirmed by Southern blot analysis of purified genomic DNA with appropriate restriction enzymes and probes. These targeted clones will be used to generate alpha2-AP deficient mice.
Okada
K
K
Center for Molecular and Vascular Biology, University of Leuven, Belgium.
Lijnen
H R
HR
Dewerchin
M
M
Belayew
A
A
Matsuo
O
O
Collen
D
D
Bernaerts
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D018274:Electroporation; D005091:Exons; D005342:Fibrinolysis; D018390:Gene Targeting; D005822:Genetic Vectors; D006801:Humans; D007438:Introns; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping; D000979:alpha-2-Antiplasmin / Q000235:genetics*
D000979:alpha-2-Antiplasmin