Cloning and characterization of the alpha 1-antichymotrypsin produced by human prostate tissue.
BACKGROUND
alpha 1-antichymotrypsin (ACT) forms stable complexes with prostate-specific antigen (PSA), a serine protease, and this complex is the major form of PSA in the blood circulation. alpha 1-antichymotrypsin occurs in the blood in approximately 10(5) molar excess to PSA, mainly due to hepatic production, but local prostatic production of ACT has been demonstrated by immunohistochemistry and in situ hybridization. The present study was performed to further characterize this prostate-produced ACT.


METHODS
The nucleotide structure of the prostatic transcript was determined from ACT coding clones isolated from prostatic cDNA. The occurrence of a prostatic ACT transcript was analyzed by Northern blot. RT-PCR was used to detect ACT transcripts in cultured prostatic cancer cells.


RESULTS
Screening of two prostatic cDNA libraries showed the frequency of ACT transcripts to be about 1 clone in 40,000. The cDNA sequence of prostatic ACT is identical to that of the previously published hepatic ACT. Northern blot analysis of mRNA extracted from prostatic tissue showed a single transcript of approximately 1.5 kb. RT-PCR analysis demonstrated an ACT transcript in cultured prostatic cancer cells.


CONCLUSIONS
In this study we provide further evidence for a local, prostatic production of ACT. The cDNA sequence data suggest that the peptide backbone of prostatic ACT is identical to the protein derived from the liver, and thus may be functional as a protease inhibitor.
Wu
G
G
Department of Urology, University of Rochester Medical Center, Rochester, New York, USA.
Lilja
H
H
Cockett
A T
AT
Gershagen
S
S
D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011467:Prostate / Q000378:metabolism*; D011470:Prostatic Hyperplasia / Q000378:metabolism / Q000473:pathology; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology; D015842:Serine Proteinase Inhibitors / Q000096:biosynthesis / Q000235:genetics*; D014407:Tumor Cells, Cultured; D000514:alpha 1-Antichymotrypsin / Q000096:biosynthesis / Q000235:genetics*
D018076:DNA, Complementary; D015842:Serine Proteinase Inhibitors; D000514:alpha 1-Antichymotrypsin