The metalloproteinases/disintegrins in the snake venom act as platelet aggregation inhibitor by an antagonism against integrin on platelet through its RGD sequence and may play other important role in cell-cell fusion, cell matrix interaction and other cellular function. Ussurin is a new metalloproteinase/disintegrin that was cloned from Gloydius ussuriensis. Poly (A+) RNA was purified from the total RNA preparation from venom gland of a single G. ussuriensis using the poly (A+) tract-mRNA isolation system. A cDNA library was constructed with the SMART PCR cDNA library construction kit. The cDNA library was screened and the positive clones were selected. The full-length cDNA of Ussurin was obtained. The cDNA encoding the Ussurin precursor has a 51bp 5'-UTR, the open reading frame of Ussurin and a 490 bp 3'-UTR, the open reading frame of Ussurin cDNA nucleotide sequence is 1434 bp and codes for 478 amino acids with a predicted molecular mass of 53.2 kD and an isoelectric point of 5.37. There is no potential N-glycosylation site in the deduced sequence region. Its deduced amino acid sequence consists of four region, a signal sequence of 18 amino acid residues, a zymogen pro-peptide of 171 amino acid residues with a cysteine switch motif (PK-MCGVT) in it, a central metalloproteinase domain of 201 amino acid residues containing a conserved zinc-chelating sequence (HEXXHXXGXXH) and a methionine-turn CIM involving zinc banding also, a space sequence between metalloproteinase domain and disintegrin domain of 15 amino acid residues with a conserved T392, T397, S400, which is specific residues of the P-II snake venom metalloproteinases, a disintegrin domain of 73 amino acid residues with a characteristic RGD region and six-disulfide bonds. Ussurin belongs to P-II class. The cDNA sequence and deduced amino acid sequence of Ussurin precursor were compared with homologous sequence in the GenBank database, the result reveals high degree of homology in sequence and organization pattern of domain with metalloproteinase/disintegrin gene family of other snake species. Compared with the alignment of amino acid sequence of metalloproteinase/disintegrin member, hypervariable regions of this member were revealed, besides they share higher homologous in the zymogen domain. It suggests that the hypervariable regions are the counterparts directly suitable for interacting with different domain of receptors, different receptors or substrates.
Amino Acid Sequence ; Animals ; Base Sequence ; Cloning, Molecular ; Disintegrins ; chemistry ; genetics ; metabolism ; Metalloproteases ; chemistry ; genetics ; metabolism ; Molecular Sequence Data ; Sequence Alignment ; Viper Venoms ; enzymology ; genetics ; Viperidae ; genetics ; metabolism

OBJECTIVETo investigate the value of a disintegrin and metalloproteinase 12 secreting form (ADAM12-S) as a maternal serum marker in second trimester screening for trisomy 21 (Down syndrome, DS), and to develop an appropriate prenatal DS screening protocol.

METHODSSerum samples were collected from 53 pregnant women carrying a trisomy 21 fetus and 621 pregnant women with matched gestational age and weight carrying a healthy fetus. ADAM12-S concentrations were determined with a time-resolved fluorescence immunoassay (TRFIA). Curve fitting by weighted regression and other statistical methods were conducted, and the model was optimized for prenatal trisomy 21 screening program in second trimester. ADAM12-S alone or in combination with other two- or three-combination test was selected as a serum marker for prenatal second-trimester screening of trisomy 21 by calculation of detection rate (DR) and false positive rate (FPR).

RESULTSBy comparison, the median multiple of the median (MoM) value of ADAM12-S in DS pregnancy group was higher than that of the control group (P< 0.01). When FPR = 5%, the DR of ADAM12-S was 28.3%, and the positive and negative likelihood ratios were 5.66 and 0.75, respectively. The DR of three-combination test of ADAM12-S, alpha-fetoprotein (AFP) and free beta subunit of human chorionic gonadotropin (β-HCG) has increased to 52.80% from 39.62% of the conventional two-combination test (AFP and free β-HCG). For women with a risk between 1/300 and 1/1000 by two-combination test for DS, the DR has increased from 39.62% to 47.12%, but FPR only increased by 0.8% after adding ADAM12-S as a maternal serum marker.

CONCLUSIONConsidering the increased DR of pregnancies with a risk between 1/300 and 1/1000 in second trimester, ADAM12-S may provide a feasible maternal serum maker when combined with AFP and free β-HCG. The cost-effectiveness ratio is reasonable.

ADAM Proteins ; blood ; ADAM12 Protein ; Biomarkers ; blood ; Disintegrins ; blood ; Down Syndrome ; blood ; diagnosis ; enzymology ; Female ; Humans ; Membrane Proteins ; blood ; Pregnancy ; Pregnancy Trimester, Second ; Prenatal Diagnosis ; methods

OBJECTIVETo get the full length of human METH1 cDNA and express it steadily in mammalian cell stably.

METHODSMETH1 was amplified by RT-PCR, and cloned into pCDNA3.0 after confirmed by sequence analysis. HepG2 cells were transfected by Lipofectamine reagent and then selected in medium with G418. The expression level of METH1 was detected by RT-PCR and Western blot.

RESULTSMETH1 with expected length was effectively amplified, and completely matched the published sequence of encoding mature peptide [GI:5725505] as shown by sequence analysis. Eukaryotic vector expressing METH1 was obtained by gene cloning, cells expressing METH1 was got by selection with G418 at 3 weeks after transfection. RT-PCR and Western blot showed high level expression of METH1.

CONCLUSIONFull length of human METH1 gene is cloned successfully and expressed in HepG2 steadily, The results set up a basis for the study of effects of METH1 on hypertrophic scar angiogenesis.

ADAM Proteins ; ADAMTS1 Protein ; Angiogenesis Inhibitors ; genetics ; metabolism ; Blotting, Western ; Cell Line, Tumor ; Cloning, Molecular ; DNA, Complementary ; genetics ; metabolism ; Disintegrins ; genetics ; metabolism ; Humans ; Metalloendopeptidases ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection ; methods