title: Cloning and characterization of a complementary DNA encoding a human epididymis-associated disintegrin and metalloprotease 7 protein.
abstract: Mammalian spermatozoa interact with the proteins secreted by the epididymis to develop fertility. Transmembrane proteins that possess a disintegrin and metalloprotease (ADAM) domains are shown to be closely related to spermatogenesis and fertilization. Our previous study demonstrated that GP-83, a glycoprotein secreted by the epididymis, was conjugated to mature sperm. In this study, a 2.1-kilobase (kb) GP-83-expressing insert was isolated from a cDNA library of human epididymis by immunoscreening using GP-83-specific antiserum. The 5' end rapid amplification of cDNA ends (RACE) and 3'-RACE of the 2.1-kb insert elucidated two isoforms of GP-83-encoding cDNA sequences, an alpha-form of 3451 base pairs (bp) and beta-form of 2643 bp. Both forms exhibit the same open reading frame of 2262 bp predicting a peptide of 754 amino acid residues. Deduced amino acid sequence revealed signal sequence, prodomain, metalloproteinase, disintegrin, cysteine-rich, epidermal growth factor-like, transmembrane, and cytoplasmic domains. The GP-83-encoding sequence was recognized as human ADAM7 due to significant homology to other ADAM7s. According to the DNA sequences elucidated in the Human Genome Project, h-ADAM7 was located at chromosome 8p22. Ex vivo expression confirmed that h-ADAM7 cDNA did encode GP-83. Northern blot analysis revealed two transcripts of 4 kb and 3 kb in the epididymis, but not in testis or other major tissues. These results indicate that the GP-83-encoding gene is a human epididymis-associated ADAM7 gene (human ADAM7, h-ADAM7) and may be involved in the sperm-egg interaction.
authors.affiliation: Graduate Institute of Life Science, National Defense Medical Center, 161, Sect. 6, Minchuan E. Rd., Taipei, Taiwan 114, Republic of China.
authors.forename: Y C
authors.initials: YC
authors.lastname: Lin
authors.forename: G H
authors.initials: GH
authors.lastname: Sun
authors.forename: Y M
authors.initials: YM
authors.lastname: Lee
authors.forename: Y W
authors.initials: YW
authors.lastname: Guo
authors.forename: H W
authors.initials: HW
authors.lastname: Liu
mesh_terms: D051722:ADAM Proteins; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015152:Blotting, Northern; D015153:Blotting, Western; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics*; D004822:Epididymis / Q000201:enzymology*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D015723:Gene Library; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics*; D008666:Metalloendopeptidases / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D018076:DNA, Complementary; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D051722:ADAM Proteins; C438783:ADAM7 protein, human; D008666:Metalloendopeptidases