Isolation and characterisation of genomic and cDNA clones for an androgen-regulated secretory protein of rat seminal vesicles

Transgelin: an androgen-dependent protein identified in the seminal vesicles of three Saharan rodents

During the breeding season, a major androgen-dependent protein with an apparent molecular weight of 21 kDa was isolated and purified from the seminal vesicles of three Saharan rodents (MLVSP21 from Meriones libycus, MSVSP21 from Meriones shawi, and MCVSP21 from Meriones crassus). The 21-kDa protein was isolated and purified from soluble seminal vesicle proteins of homogenate by one-dimensional polyacrylamide gel electrophoresis (SDS-PAGE). Using polyclonal antibodies directed against POSVP21 (Psammomys obesus seminal vesicles protein of 21 kDa), a major androgen-dependent secretory protein from sand rat seminal vesicles, identified previously as transgelin, we showed an immunological homology with POSVP21 by immunoblotting. These three major androgen-dependent proteins with a same apparent molecular weight of 21 kDa designated as MLVSP21 (Meriones libycus seminal vesicles protein of 21 kDa), MSVSP21 (Meriones shawi seminal vesicles protein of 21 kDa), and MCVSP21 (Meriones crassus seminal vesicles protein of 21 kDa) were localized by immunohistochemistry and identified by applying a proteomic approach. Our results indicated that the isolated proteins MLSVP21, MSSVP21, and MCSVP21 seem to correspond to the same protein: the transgelin. So that transgelin can be used as a specific marker of these rodent physiological reproduction mechanisms.

The promoter of an androgen dependent gene in the hamster flank organ

Hamster flank organs are useful for studying androgen-dependent growth of hair follicles and sebaceous glands. A cDNA clone (FAR-17a) was isolated from the hamster flank organ, whose expression was highly sensitive to androgen. The mRNA level of this gene was reduced after castration but reappeared after testosterone treatment. To elucidate the mechanism of expression of this gene regulated by androgen we isolated a genomic clone, from a hamster genomic library, that includes the promoter and upsteam region. The promoter region was used to drive a luciferase reporter gene in Cos 7 cells. This construct was activated five to six times higher over a control plasmid lacking the promoter region. We tested the effects of testosterone by transfection of the reporter plasmid into androgen dependent SC-3 cells. The results showed up to fivefold stimulation after the addition of androgen. The sequence of this promoter region was analyzed and the transcription factor binding sites were predicted. Since no obvious androgen responsive elements were included in the promoter region, we suggest that the stimulation of the reporter construct has to be mediated indirectly by androgen-dependent transcription factor(s).

Photoperiod-induced changes in the proteins secreted by the male genital tract of the rodent Octodon degus

The proteins secreted by the male genital tract were analyzed in the seasonally breeding rodent Octodon degus. The protein patterns from the fluids collected from sexually active animals were compared with those from animals in resting period, with others which were previously castrated, and with castrated animals which received testosterone replacement treatment. Fluids from cauda epididymides (CE), seminal vesicles (SV) and prostate glands (PG) were collected, and analyzed by polyacrylamide gel electrophoresis followed by different staining methods and densitometry. Modifications were detected in the protein patterns of resting or castrated animals. In CE fluid, the decrease of one protein band (45 Kda) and the uprising of another (210 Kda) were recognized after castration. In animals during resting period the changes were not as marked as in castrated animals. SV secretion demonstrated a similar response to resting phase and castration, because Protein SVS I (200 Kda) decreased or were not observed when these conditions occurred. PG fluid proteins were also modified after castration. In general, the more severe changes in the protein spectrum were induced by castration, despite radioimmunoassay showing that testosterone fall is even higher in resting period animals than in those castrated. Testosterone replacement resulted in recovery of a protein profile which is very similar to that of sexually active males. Results suggest that the androgenic control of male tract secretions would be rather different in this seasonal hystrichomorph when compared to the regulation system described for myomorph rodents.

Sequence analysis and characterization of FAR-17c, an androgen-dependent gene in the flank organs of hamsters

This study reports on the isolation and characterization of a cDNA clone, regulated by androgen transcriptionally, in male Golden hamsters' flank organs. Previous studies have reported on the cloning of an androgen-dependent gene, FAR-17a, from the same hamster organ. After castration, the FAR-17c transcription rate decreases faster than FAR-17a but is not suppressed completely. The recovery of transcription by androgen injection is also faster than FAR-17a. In male hamsters, it is expressed strongly in the sebaceous glands and liver, and weakly in the lungs and brain. It has never been expressed in the testes. In the female, it is strongly expressed in the liver and brain and weakly in the lungs and flank organs. Sequence analysis shows that FAR-17c has a long 1062 bp open reading frame and its deduced amino acid sequence (354 residues) is highly homologous to the stearyl-CoA desaturases of the rat liver and mouse adipocytes. Stearyl-CoA desaturase, either in the liver or adipocytes appears to be independent of androgen regulation. Since stearyl-CoA desaturase plays a key role in fatty acid metabolism, further studies on its regulation by androgen are warranted in relation to acne vulgaris.

Cloning and chromosomal mapping of mouse seminal vesicle protein F

Seminal vesicle proteins (SVPs) are made by male rodents, and form the copulatory plug following mating. Here we report a partial nucleotide sequence of a mouse clone homologous to rat SVP F. Unexpectedly, we found that SVP F-related transcripts are expressed at high levels in mouse skeletal muscle. We mapped mouse SVP F to mouse chromosome 15 using somatic cell hybrid lines.

Isolation and characterization of cDNA for an androgen-regulated mRNA in the flank organ of hamsters

Flank organs of hamster are useful for studying androgen-dependent growth of hair follicles and sebaceous glands. To elucidate the mechanism of gene expression regulated by androgen, we constructed a cDNA library from flank organs of male hamsters and screened by a differential hybridization method using cDNA probes from normal and castrated males. We isolated a cDNA clone, termed FAR-17a, whose expression was found to be highly sensitive to androgen. FAR-17a mRNA of 1.8 kb was reduced after castration and reappeared after testosterone treatments. Among several tissues examined, FAR-17a gene was expressed at a high level in flank organ and a low level in testis and earlobe. FAR-17a probe detected a few fragments in genomic DNA of hamster, mouse, suncus, pig, and human, suggesting that this gene is phylogenetically conserved. The sequence of FAR-17a cDNA predicts a protein of 231 amino acids (27,216 daltons) having basic properties. The deduced protein has no significant homologies to proteins previously described.

Effects of androgens on the transcription of secretory protein genes in rat seminal vesicle

Run-on transcription in isolated nuclei has been used to study the effects of testosterone on gene expression in rat seminal vesicles. General transcriptional rates were increased by about 6-fold with an additional 2- to 3-fold differential stimulation of the genes for secretory proteins IV and V. These transcriptional changes are insufficient to explain overall changes in cellular mRNA levels, indicating that androgens must also have major effects on post-transcriptional processing of RNA transcripts or on mRNA stability. Analysis of nuclear RNA by Northern blotting with intron probes suggests substantial androgen effects on primary transcript processing.

Androgen regulation of a specific gene in hamster flank organs

Flank organs of Golden Syrian hamster containing large sebaceous glands are a useful model for studying androgen-dependent gene expression. Recently, we have isolated an androgen-dependent gene from a cDNA library constructed from male mRNAs of flank organs. In the present study, using this gene as a probe, we examined the kinetics of loss and re-expression of the mRNA of this gene. Dot blot hybridization, the current method, can approximately quantify mRNA levels. Castration caused a marked decrease in the mRNA within a few days to undetectable levels. Topical application of testosterone re-activated the mRNA levels, with the earliest activation within 24 h. The results of various topical steroid applications showed a full re-activation of the mRNA by testosterone and dihydrotestosterone, partial re-activation by androstanedione and androstenedione, and no activation by androstanediol or dehydroepiandrosterone. Simultaneous application of testosterone and progesterone inhibited the expression of mRNA but application of dihydrotestosterone and progesterone did not. The current dot blot hybridization technique appears to be a more direct approach for studying androgen action on DNAs than other previously used methods such as morphometry or enzyme assay.

Androgen regulation of the mRNA encoding a major protein of the mouse vas deferens

A cDNA encoding the major mouse vas deferens protein (MVDP) has been cloned and characterized. Using in situ hybridization we have identified the epithelial cells of the vas deferens as the site of synthesis of MVDP mRNA. Northern blot analysis suggests that a high level of an mRNA corresponding to the MVDP gene is present in the mouse vas deferens whereas the amount of MVDP mRNA in vas deferens of other species studied, or in other mouse tissues, even if present, is undetectable. Steady-state levels of MVDP mRNA are decreased by approximately 42% 3 days after castration but a significant hybridization signal is still observed even 50 days after castration. Testosterone treatment for 2 weeks is necessary to completely reverse the effect of castration. In vitro transcription assays on isolated nuclei showed that the hormonal induction of the MVDP gene is achieved mainly at transcriptional level.

Developmental pattern of androgen-regulated proteins in seminal vesicles from the mouse

Proteins from secretions or homogenates of mice seminal vesicles were analysed by polyacrylamide gel electrophoresis. In homogenates about 15 bands were differentially induced with molecular weights (MW's) of 12, 13, 14, 15, 15.5, 71, 120 and 140 kD, or repressed molecular weights of 12.5, 14.3, 28, 30, 53, 73, 90-105 kD). The effects of castration were reversed by testosterone and dihydrotestosterone but not by oestradiol, progesterone or corticosterone. When the androgen-dependence of proteins was investigated using radioactive methionine the protein spectra showed that about 12 bands with molecular weights of 13, 13.7, 14, 15, 15.5, 16, 20.5, 24, 37, 38.5, 56, 68, 96 and 180 kD were differentially induced or repressed by androgens. Of the induced proteins, those with low molecular weight (12-15.5 kD) were accumulated in significant amounts between 20 days and 30 days, coincident with the pubertal increase of androgens in the seminal vesicles. Those induced proteins with high molecular weight (71, 120 and 140 kD) appeared between 40 days and 60 days. The androgen-repressed proteins were strongly evident in immature males, but disappeared after day 40.

Structure of the androgen dependent SVS VI protein as derived from cDNA

The 11S poly(A+)RNA from rat seminal vesicle was cloned. By hybrid selection of clones reacting to the low molecular weight region of the 11S peak, a clone containing a new seminal vesicle cDNA sequence called SVS VI was isolated. The DNA sequence of two overlapping cDNAs (pSV24 and pSV33) is presented. The sequence of SVS VI was compared to the previously isolated SVS IV and SVS V cDNAS. Dot hybridization showed that SVS VI is androgen responsive after giving testosterone to castrated rats. The hydrophilicity was analyzed using standard Bionet procedures. All three proteins are extremely variable, rich in alpha-helix and very water soluble. The computer predicted hydrophilicity is compared for SVS VI, V and IV. A small region in the 3'-non-coding area of SVS VI has high similarity to a region in SVS IV mRNA.

Comparison of seminal vesicle secretory proteins of rodents using antibody and nucleotide probes

The copulatory vaginal plug is a conspicuous feature of rodent reproduction. The five major seminal vesicle secretory proteins of Rattus norvegicus (proteins I-V), which form the copulatory plug, constitute a closely related androgen-regulated family that appears to share a common evolutionary origin. The relationships between these rat proteins and the major seminal vesicle proteins of other rodents were explored using antibodies specific for the individual rat proteins. Immunoblotting of proteins separated by SDS-PAGE showed that the vesicular proteins of R. rattus are identical to those of R. norvegicus except for an additional protein related to protein III. No differences were seen in inbred and outbred strains of R. norvegicus. Of the major proteins of Mus musculus, one showed strong homology with rat protein II and three others were weakly homologous to proteins I, IV (or S) and V (or F); none showed homology to rat protein III. The only homology between the vesicular proteins of Mesocricetus auratus (Syrian hamster) and Meriones ungulatus (Mongolian gerbil) was with rat protein II while those of Cavia porcellus (guinea pig) showed no homology at all with the rat proteins. In addition, cDNA probes for rat genes IV and V both detected weak homologues in seminal vesicle RNA from mice but not guinea pigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue distribution, developmental profile and hormonal regulation of androgen-responsive secretory proteins of rat seminal vesicles studied by immunocytochemistry

The seminal vesicles of the rat synthesise large amounts of androgen-regulated secretory proteins. Indirect immunofluorescence cytochemistry and immunoblotting with monospecific polyclonal antibodies against three of the major secretory proteins (II, S and F) have been used to investigate the tissue distribution, subcellular localisation, androgen-regulation and developmental profile of secretory protein synthesis. There was no evidence for regional specialisation of the seminal vesicle epithelium; every epithelial cell synthesizes all three proteins via a classical secretory involving storage in secretory vesicles. Proteins S and II are contained within the same secretory vesicles. The time course of deinduction of proteins S and F after castration and their reinduction by testosterone closely followed that for their specific mRNAs described previously. During development, proteins S and F first appear between 10 and 15 days after birth. A protein immunologically related to seminal vesicle protein II is present in the lateral and dorsal lobes of the prostatic complex.

Effect of androgens on mRNA for a secretory protein of rat dorsolateral prostate and seminal vesicles

The androgen dependence of a highly abundant mRNA found in the rat dorsolateral prostate and seminal vesicles has been investigated using a complementary DNA clone from a rat dorsal prostate library. The 1.5 kilobase (kb) mRNA codes for a 52 000 Da translation product which is processed to 49 000 Da in the presence of microsomal membranes. This product appears to correspond to the previously described SVS II protein secreted by rat seminal vesicles and can be immunoprecipitated with anti-SVS II antiserum. Dot hybridization assays indicated that the mRNA is abundant in the dorsal and lateral prostate glands and in seminal vesicles but not in the ventral prostate, coagulating gland or other non-accessory sex tissues. Castration of mature male rats reduces the 1.5 kb mRNA 10-fold in the seminal vesicles and 7-fold in the dorsolateral prostate in 9 days. Androgen administration to one-week castrates returned the mRNA level to normal in both tissues within 48 h. The levels of the 1.5 kb mRNA are very similar in the dorsolateral prostate and seminal vesicles at maturity but distinct patterns of developmental regulation of this gene exist in the two tissues. Between 3 and 6 weeks of age, the level of the 1.5 kb mRNA increases approximately 3-fold in the dorsolateral prostate while the increase in the seminal vesicles is more than 600-fold.

The effects of androgen on the transcription of specific genes in guinea pig seminal vesicle epithelium

Steroid hormones have been shown to have highly differential effects on the expression of abundant cell-specific protein genes in a multitude of model tissues. In rat seminal vesicle, for example, DNA clones representing two major secretory protein genes have been used to show that both of the genes are differentially regulated by androgen. In this paper, we have examined the effects of androgen on the transcription of two major secretory protein genes in guinea pig seminal vesicle epithelium. Nuclear run-off experiments were used to show that castration of the adult resulted in a 3-fold decrease in total transcription activity. Surprisingly, the decrease in total transcriptional activity was not reflected in a differential decrease in the transcriptional activity of the two major secretory protein genes. When the effects of castration on the transcriptional activity of the major secretory protein genes were compared to the effects on other genes, it was found that the transcriptional activity of each gene examined was decreased by the same magnitude as the major secretory protein genes. Similarly, the transcriptional activity of every gene examined increased by the same magnitude as the major secretory protein genes during hormone repletion of the castrated adult. Thus, in contrast to the differential effects of steroids on the transcription of abundant cell-specific proteins in many other steroid-dependent tissues, the transcription of major secretory proteins in guinea pig seminal vesicle epithelium appears to be regulated in parallel with many other genes. The generalized effects of androgen on transcriptional activity could account for the generalized effects of androgen on seminal vesicle epithelial cell structure and function.

Androgen-regulated proteins of rat seminal vesicle secretion constitute a structurally related family present in the copulatory plug

All the major androgen-regulated secretory proteins of rat seminal vesicles have been purified in high yield from polyacrylamide gels using electroelution. In the process a sixth previously undocumented protein has been identified. Amino acid compositions of all the proteins are very similar and highly unusual, being high in lysine and arginine, and with 40-50% of the residues accounted for by serine, glycine and glutamate/glutamine. N-Terminal amino acid sequences for 3 of the proteins show that they are clearly the products of related genes. At least one of the other proteins is N-terminally blocked in vivo. Antibodies specific for each protein have been raised and provide evidence of structural similarity between the proteins. The antibodies were also used in immunofluorescence histochemistry with the rat copulatory plug, showing for the first time that all the major proteins of seminal vesicle secretion are components of this reproductive structure.

Sequence organisation of rat seminal vesicle F gene: location of transcriptional start point and sequence comparison with six other androgen-regulated genes

Seminal vesicle F gene, encoding an androgen-regulated serine-rich structural protein of the rat copulatory plug, has been sequenced together with 5' and 3' flanking regions. The intron/exon arrangement of the gene deduced from restriction maps was confirmed. The major and possible minor transcriptional start points were located by primer extension analysis and S1 nuclease mapping. A published nucleotide sequence for seminal vesicle S gene which also encodes an androgen-regulated protein of the copulatory plug has been extended to allow comparison of F and S genes. The considerable sequence homology between the two genes confirms their evolutionary relatedness. Homology is especially high in their promoter regions and their transcriptional start points are identical. They share several regions of dyad symmetry including one just upstream of the promoter. The upstream regions of F and S genes were compared with those of five other androgen-responsive rodent genes in an attempt to identify common sequence motifs that might be involved in hormonal regulation of gene expression.

Androgen regulation of specific mRNAs, endoplasmic reticulum and Golgi-system

The seminal vesicles of male rat secrete tissue-specific proteins under androgenic control. The effects of testosterone on the rough endoplasmic reticulum (RER) and Golgi-system of this tissue have been quantified using specific antibodies. Castration was followed within 2 weeks by a 10-fold reduction in RER-specific membrane protein. This was reversed by testosterone commencing about 4 h after exposure to the hormone. Five individual major RER antigens were separately quantified; these changed coordinately in response to androgen. No hormone-induced changes were seen in Golgi-specific membrane protein. Hormonal effects on mRNAs for two major secretory proteins were also measured using hybridisation to specific cDNA probes. The cellular concentrations of the two mRNAs changed by at least 1000-fold during hormonal treatment. A detailed examination of the time-course of induction by testosterone failed to show any temporal distinction between effects on mRNA and RER.