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D Bossyns

Publications and source records attributed to D Bossyns.

6 recordsLinked to original sources
PubMed1986

Influence of castration and androgen treatment on the synthesis of prostatic binding protein and the concentration of its mRNA in the rat ventral prostate.

The regulation by androgens of the synthesis of prostatic binding protein (PBP), an abundant secretory protein of the rat ventral prostate, was studied by measuring the rate of incorporation of [3H]leucine into total protein and into PBP by prostatic tissue in vitro. PBP-specific synthesis dropped to 30% of the intact level after 3 days and to 5.5% after 7 days. Administration of androgens to 7 day-castrated rats reversed these changes: 36% of the control value was reached after 3 days of treatment and 70% after 5 days. The mRNAs of PBP were measured under similar conditions by means of dot hybridization, using C1-, C2- and C3-specific cDNA-clones. The 3 mRNAs followed a parallel course. They decreased to about 18% on the third day after castration and to about 2% after 7 days. Androgen treatment of 7-day castrated rats produced a small increase of these levels after 1 day. After 3 days 15% of the intact level was reached. The general similarity of the time course of PBP synthesis and PBP mRNA levels in castrated and androgen treated rats supports a transcriptional regulation mechanism, although there also is some evidence for an influence on protein synthesis in general.

Androgen-Binding Protein↗
PubMed1983

Proline-rich polypeptides bound to rat prostatic binding protein. The primary structure of the two main components, proline-rich polypeptides IV and V.

The complete primary structures of the two main forms, PRP-IV and PRP-V, of a proline-rich polypeptide bound in vivo to rat prostatic binding protein has been determined. Their sequences were established using manual Edman degradation of the native polypeptide and of purified fragments derived from trypsin and thermolysin digestions. Both polypeptides contain 38 amino acid residues (Mr = 4397 and 4339); cysteine, methionine, and serine are missing. In spite of the high proline content (21%), no polyproline stretches were detected. PRP-IV and PRP-V show an extensive structural homology and differ only by three substitutions. These amino acid replacements are located in the NH2-terminal part of the molecule at positions 6 (His leads to Pro), 10 (Pro leads to His), and 11 (Asp leads to Gly). Moreover, each component displays a microheterogeneity at several positions in the sequence which indicates that multiple structural variants exist for PRP-IV and PRP-V. These data not only suggest the existence in rat ventral prostate of a multigene family coding for the proline-rich polypeptides but also the occurrence of a pronounced genetic polymorphism for these components. In addition, a remarkable sequence homology is observed between the PRP components and the region of the B chain in the precursor of mouse renin.

Amino Acid Sequence↗
PubMed1983

Multiple forms of the proline-rich polypeptide (PRP) bound to rat prostatic binding protein.

The proline-rich polypeptide, that is bound to rat prostatic binding protein displays a marked heterogeneity on isoelectric focusing, with major bands at pH 7.6 and pH 6.9. The same complex pattern is obtained for PRP prepared from prostates of individual rats from several strains. Using carboxymethylcellulose chromatography 6 different forms of PRP can be separated. Five of them have the same size (MW : 4000) and respectively glycine and lysine as N- and C-terminal amino acid. Their amino acid composition suggests that these forms differ by internal substitution respectively of aspartic acid and glycine and of proline and histidine. The sixth form (MW : 3500) lacks several amino acids at its N-terminal.

Amino Acids↗
PubMed1983

A comparative study of estramustine and pregnenolone binding to prostatic binding protein: evidence for subunit cooperativity.

The binding of estramustine, a nitrogen mustard derivative of oestradiol to purified rat prostatic binding protein was studied as a test for a possible identity between this protein and the very similar estramustine-binding protein, described by Forsgren et al. In accordance with this hypothesis estramustine binds to purified prostatic binding protein with a high affinity (2.5 X 10(7)M-1). This affinity markedly exceeds the affinity of pregnenolone for this protein (0.9 X 10(6)M-1) or for a complex of prostatic binding protein, with prostatic proline-rich polypeptide, (4.7 X 10(6)M-1). In competition experiments estramustine completely suppresses the binding of [3H]pregnenolone, whereas the binding of [3H]estramustine is only partially suppressed by pregnenolone, even at high concentrations. Prostatic binding protein was separated in its F- and S-subunit by DEAE-Sepharose chromatography performed in the presence of 8 M urea. Only the S-subunit, most probably in its dimer form, displays marked estramustine and pregnenolone binding, with affinities of respectively 3.7 and 1.2 X 10(6)M-1. Recombination of both subunits results in a strong increase of estramustine binding, but not of pregnenolone binding.

Androgen-Binding Protein↗
PubMed1982

Study of a proline-rich polypeptide bound to the prostatic binding protein of rat ventral prostate.

A proline-rich polypeptide is associated with prostatic binding protein, a major androgen-dependent protein described previously in the rat ventral prostate. This polypeptide has been purified. Its molecular weight estimated by gel filtration is about 8500, but a markedly lower value (3300) is obtained by sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis. Isoelectric focusing on thin layer polyacrylamide gels yields two major forms with isoelectric points of, respectively, 7.75 and 7.05. The amino acid composition of proline-rich polypeptide is characterized by a high (19.5%) proline content and its NH2-terminal amino acid is glycine. Like prostatic binding protein, proline-rich polypeptide is a characteristic component of the rat ventral prostate and localized primarily in the intraluminal secretion of this gland. In intact adult male rats the cytosol of a whole gland contains 0.70 +/- 0.15 (S.D.) mg of the polypeptide, as measured by radial immunodiffusion or 2.6 +/- 0.5% of (S.D.) of the total protein. This amount decreases gradually after castration and becomes undetectable after 8 days. Androgen treatment, on the other hand, results in a rapid stimulation, while estradiol and progesterone are ineffective. Proline-rich polypeptide is markedly more androgen-dependent than prostatic binding protein, and promises to be an interesting end point for studies on the mechanism of action of androgens.

Amino Acids↗