Biomedical subjects

F S French

Publications and source records attributed to F S French.

At least 73 records · Page 4Linked to original sources

PubMed1989

Regulation of c-fos messenger ribonucleic acid by fibroblast growth factor in cultured Sertoli cells.

The data reported here demonstrate that basic FGF and Sertoli-cell-derived FGF have rapid stimulatory effects on c-fos mRNA levels. Basic FGF appears to utilize a signal transduction pathway that is distinct from that used by FSH and serum but similar in its potency and transiency. This is consistent with other reports in the literature on FGFs mechanism of action. For example, a monoclonal antibody to phosphatidyl 4,5-biphosphate will block the effects of PDGF on thymidine incorporation into NIH 3T3 cells but has no effect on basic FGF. Our data support the emerging possibility of a novel pathway mediating FGF actions. A similar precedent has been established for serotonin-induced DNA synthesis in smooth muscle cells. The rat Sertoli cell, with both FSH and FGF rapidly inducing c-fos, is an excellent model system for addressing the mechanism of action of basic FGF, the specificity of the c-fos response and the role of FGF in the reproductive system. Stimulation of c-fos mRNA by basic FGF in the cultured Sertoli cell presents questions regarding the role of FGF and c-fos in the male reproductive system. Basic FGF has been shown to stimulate cell division and plasminogen activator activity in cultured immature porcine Sertoli cells. Plasminogen activator may play a critical role in the tissue remodeling required for spermiogenesis. Interestingly, fos has been shown to be expressed preferentially in pachytene spermatocytes in the mouse. These observations taken together with the finding that basic FGF mRNA levels in Xenopus oocytes are markedly elevated, suggests that basic FGF may be important for Sertoli cell function, spermatogonial cell proliferation and subsequent meiotic and sperm maturational events.

Animals↗

PubMed1989

Developmental expression of an androgen-regulated epididymal protein.

Acidic epididymal glycoprotein (AEG), an androgen-regulated secretory protein of rat epididymis, was quantitated by RIA in epididymal extracts of rats of increasing age. Although detectable at 1 day of age, significant concentrations of AEG were not measured until 20 days; concentrations increased steadily, so that by 120 days of age, AEG represented 10% of total soluble protein. AEG mRNA was detected by Northern blot analysis of RNA from epididymides of 5-day-old animals and rapidly increased in amount between 20 and 35 days, reaching a maximum at 45 days. Using immunohistochemistry, AEG was localized in epididymal epithelial cells at 1 day of age. The number of cells staining for AEG increased markedly after 15 days. At 120 days, the immunoreactivity was predominantly localized to the lumen of the epithelial duct. To delineate factors that may influence AEG expression in the developing epididymis, we measured concentrations of androgen and androgen receptor mRNA in tissue extracts prepared from animals of various ages. Androgen receptor mRNA was detectable in epididymal extracts isolated from 1- to 90-day-old animals. Epididymal androgen concentrations were high at all ages (range, 6.0-31.2 ng/g tissue). The marked increase in AEG mRNA concentration at 20 days of age was not associated with an increase in either androgen or androgen receptor mRNA concentrations, suggesting that other factors may be necessary for AEG expression.

Aging↗

PubMed1989

Cortisol alters gene expression during involution of the rat ventral prostate.

The ability of high doses of cortisol to retard the involution process in the rat ventral prostate was related to alterations in the pattern of gene expression. Poly(A)+ RNA preparations from the prostates of noncastrated, castrated, and castrated rats injected daily for 7 days with cortisol were compared by Northern blot hybridizations for the relative expression of genes associated with cell differentiation and maintenance (the C1 prostatic steroid binding protein gene and alpha-tubulin), with cell death (TRPM-2, hsp 70, and c-fos), and with hormone regulation (the androgen and glucocorticoid receptors). As anticipated, the concentration of C1 mRNA in the prostate fell to less than 4% of that in the noncastrated controls within 4 days after castration and was nearly undetectable after 7 days. This decline was retarded by cortisol treatment of 7-day castrated animals which sustained the level of C1 transcripts at approximately 50% of control. While the pattern of expression of alpha-tubulin indicated some minor fluctuations, with the highest level occurring 7 days after castration, the prostates of the cortisol-treated group had essentially the same concentration of this mRNA as the noncastrates. Cortisol also modified the expression of genes associated with prostatic cell death. The large increase in prostatic TRPM-2 mRNA, seen 7 days after castration, was reduced by over 80% after treatment with the glucocorticoid. Although not as abundantly expressed as TRPM-2, the castration-induced levels of transcripts for both hsp 70 and the protooncogene c-fos were substantially reduced by cortisol.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

A rat Sertoli cell factor similar to basic fibroblast growth factor increases c-fos messenger ribonucleic acid in cultured Sertoli cells.

We have shown that the cultured Sertoli cell from the immature rat contains a fibroblast growth factor (FGF)-like factor. It behaves as a cationic peptide, is a potent competence factor for BALB/c3T3 mouse embryo fibroblasts, and displays a high affinity for heparin. Both bovine basic FGF and Sertoli cell FGF-like factor rapidly increase c-fos mRNA in cultured Sertoli cells. FSH, serum, and phorbol esters individually stimulate c-fos in cultured Sertoli cells whereas platelet-derived growth factor, epidermal growth factor, and insulin-like growth factor-I have little affect. However, unlike FSH, basic FGF does not stimulate an increase in cAMP and unlike either serum or phorbol esters, basic FGF does not stimulate phosphoinositol turnover or intracellular calcium changes. When Sertoli cell protein kinase C activity is suppressed by preexposure to phorbol ester, basic FGF continues to be a potent stimulator of c-fos, indicating that the calcium/phospholipid pathway is not involved in FGF induction. Basic FGF and FSH also increase jun-B mRNA levels in cultured Sertoli cells. In response to FGF, jun-B is more transiently increased than c-fos. In contrast, in response to FSH, jun-B persists longer than c-fos. These results indicate that cultured Sertoli cells contain a FGF-like factor that increases c-fos mRNA via a mechanism not involving cAMP and the calcium/phospholipid pathways. The different responsiveness of c-fos and jun-B to FSH and basic FGF may explain differences in the ultimate actions of these two ligands.

Animals↗

PubMed1989

Androgen receptor locus on the human X chromosome: regional localization to Xq11-12 and description of a DNA polymorphism.

The gene for the androgen receptor, mutations at which cause the X-linked androgen insensitivity syndrome, has been localized to the q11----q12 region of the human X chromosome by analysis, using a cloned cDNA for the androgen receptor, of somatic cell hybrid panels segregating portions of the X chromosome. A moderate-frequency HindIII RFLP has been found which should be useful in genetic linkage analysis of the various inherited forms of androgen insensitivity.

Animals↗

PubMed1988

Regulation of the beta 2-adrenergic receptor and its mRNA in the rat ventral prostate by testosterone.

To investigate the regulation of beta 2AR expression in rat ventral prostate the effects of castration and testosterone replacement on the beta 2AR were studied by ligand binding and Northern blot analysis. Orchidectomy depressed beta 2AR number by 50% within 4 days and testosterone administration to 4-day castrates produced a rapid and complete recovery of beta 2AR number within 24 h. In contrast to receptor number, beta 2AR mRNA levels did not change relative to total RNA following castration. However, during the testosterone replacement period beta 2AR mRNA levels rose transiently, reaching a maximum (3.5-fold) between 8 and 12 h, and this increase in mRNA preceded the recovery in beta 2AR number in the membrane. Regulation of beta 2AR gene expression by testosterone in the ventral prostate is thus complex and probably involves both transcriptional and post-transcriptional components.

Animals↗

PubMed1988

Cloning of human androgen receptor complementary DNA and localization to the X chromosome.

The androgen receptor (AR) mediates the actions of male sex steroids. Human AR genomic DNA was cloned from a flow-sorted human X chromosome library by using a consensus nucleotide sequence from the DNA-binding domain of the family of nuclear receptors. The AR gene was localized on the human X chromosome between the centromere and q13. Cloned complementary DNA, selected with an AR-specific oligonucleotide probe, was expressed in monkey kidney (COS) cells and yielded a high-affinity androgen-binding protein with steroid-binding specificity corresponding to that of native AR. A predominant messenger RNA species of 9.6 kilobases was identified in human, rat, and mouse tissues known to contain AR and was undetectable in tissues lacking AR androgen-binding activity, including kidney and liver from androgen-insensitive mice. The deduced amino acid sequence of AR within the DNA-binding domain has highest sequence identity with the progesterone receptor.

Amino Acid Sequence↗

PubMed1988

Oncogene expression in prostate cancer: Dunning R3327 rat dorsal prostatic adenocarcinoma system.

Steady-state levels of myc, fos, p53, sis, and neu mRNAs were measured in eight variants derived from the Dunning R3327 rat prostate adenocarcinoma and compared to levels in normal dorsal prostate. Expression of the myb and erbB oncogenes in the Dunning tumors was below the limits of detection. Myc, p53, and sis mRNA levels in all tumors were at or above control levels. Fos mRNA levels were below control levels in four of five anaplastic tumors and were above control levels in the remaining tumors. A comparison of mRNA levels along the two Dunning lineages revealed that increased expression of these oncogenes did not correlate with tumor progression.

Adenocarcinoma↗

PubMed1988

Expression of ras proto-oncogenes in the Dunning R3327 rat prostatic adenocarcinoma system.

Steady-state levels of c-Ha-ras mRNA were measured in eight sublines of the Dunning R3327 rat prostatic adenocarcinoma. As a control, normal dorsal prostate tissue was studied. Increased expression of c-Ha-ras is associated with tumor progression in one lineage of the Dunning R3327 system (H to AT1 to MAT-Lu and MAT-Ly-Lu). Here ras mRNA increases as the tumor advances from androgen dependence and a high degree of differentiation to an anaplastic aneuploid phenotype with high metastatic potential. However, in the other Dunning lineage (H to HI to HI-F to AT3), expression of c-Ha-ras is variable and does not correlate with tumor progression. Immunocytochemistry showed that levels of the c-Ha-ras p21 protein paralleled steady-state mRNA levels in variants. Transfection assays, using NIH/3T3 cells, suggested that the ras loci were not activated in the R3327 tumors. Levels of c-Ki-ras mRNA were also measured in the Dunning tumors; these did not correlate with tumor progression in either lineage. Expression of N-ras mRNA was not detected in the Dunning tumors.

Adenocarcinoma↗

PubMed1988

Deletion of the steroid-binding domain of the human androgen receptor gene in one family with complete androgen insensitivity syndrome: evidence for further genetic heterogeneity in this syndrome.

The cloning of a cDNA for the human androgen receptor gene has resulted in the availability of cDNA probes that span various parts of the gene, including the entire steroid-binding domain and part of the DNA-binding domain, as well as part of the 5' region of the gene. The radiolabeled probes were used to screen for androgen receptor mutations on Southern blots prepared by restriction endonuclease digestion of genomic DNA from human subjects with complete androgen insensitivity syndrome (AIS). In this investigation, we considered only patients presenting complete AIS and with the androgen receptor (-) form as the most probable subjects to show a gene deletion. One subject from each of six unrelated families with the receptor (-) form of complete AIS and 10 normal subjects (6 females and 4 males) were studied. In the 10 normal subjects and in 5 of the 6 patients, identical DNA restriction fragment patterns were observed with EcoRI and BamHI. In one affected individual, a partial deletion of the androgen receptor gene involving the steroid-binding domain was detected. Analysis of other members of this family confirmed the apparent gene deletion. Our data provide direct proof that complete AIS in some families can result from a deletion of the androgen receptor structural gene. However, other families do not demonstrate such a deletion, suggesting that point mutations (or small, undetectable deletions) may also result in the receptor (-) form of complete AIS, adding further to the genetic heterogeneity of this syndrome.

Blotting, Southern↗

PubMed1988

Structure of the rat androgen-binding protein gene.

To study hormonal regulation of rat androgen-binding protein (ABP) we have cloned and sequenced the gene. A 5.3-kbp genomic DNA fragment was found to contain the entire coding region of the gene, which consists of 8 exons. The major site of transcription initiation in the testis was localized by primer extension and is located 36 bases upstream from the site of translation initiation. The gene does not contain a "TATA box" immediately upstream from the major start site. The sequence TACCTA occurs at residue -23, which is a functional TATA-like element in the SV40 major late gene. A sequence related to the cAMP response element is at residue -126 bp. Southern blot analysis of rat genomic DNA indicated a single gene for ABP in the rat. The existence of one gene supports the idea that sex steroid-binding protein (SBP) produced by fetal rat liver is coded by the same gene. The possibility that an alternate promoter region is active in the fetal liver is discussed.

Androgen-Binding Protein↗

PubMed1988

The gene structure of rat androgen-binding protein: identification of potential regulatory deoxyribonucleic acid elements of a follicle-stimulating hormone-regulated protein.

A genomic clone has been characterized for androgen-binding protein (ABP), a Sertoli cell secretory protein that is regulated by androgens and FSH. A 5.3-kilobase pair Sstl DNA fragment was sequenced and found to contain the entire coding region of the gene, which is divided into 8 exons. The major transcription initiation site in the testis was localized by primer extension with two unique oligomers. In addition, a minor initiation site was identified that appears to originate from another promoter. The gene does not contain a conventional TATA box immediately upstream from the major start site; rather, the sequence TACCTA occurs at residue -24. This sequence has been described functionally as a TATA-like element in the SV40 major late gene. Other potential regulatory elements include a sequence related to the cAMP response element at residue -126 base pair. Using primary Sertoli cell cultures, it was found that (Bu)2cAMP or FSH increases ABP mRNA levels 3-5 fold, with a 2-fold increase in the level of secreted ABP. Southern blot analysis of rat genomic DNA indicated that there is a single gene for ABP in the rat. The existence of one gene supports the idea that sex hormone binding globulin produced by fetal rat liver is coded by the same gene.

Amino Acid Sequence↗

PubMed1988

Follicle-stimulating hormone induces transient expression of the protooncogene c-fos in primary Sertoli cell cultures.

The expression of the protooncogene c-fos has been associated with the transduction of cell surface stimuli into changes in nuclear function. To evaluate the possibility that this protooncogene plays a role in the gonadotropin-dependent gene regulation, the effect of FSH on the expression of c-fos was studied in primary Sertoli cell cultures. Sertoli cells were stimulated for different time intervals with FSH and c-fos mRNA levels measured by Northern RNA blot analysis. FSH treatment increased c-fos mRNA transiently with a maximal stimulation reached in 1 h. The level of c-fos mRNA returned to basal level within 4-6 h. The induction of c-fos mRNA was dependent on the concentration of FSH used with an ED50 of 3-5 ng/ml ovine FSH-16. A similar increase in c-fos expression was induced with highly purified hFSH. The c-fos mRNA was also elevated after treatment of the Sertoli cell with (Bu)2cAMP and forskolin. (Bu)2cAMP treatment led to a sustained induction of c-fos mRNA, with increased mRNA levels being maintained after 12 h. The FSH-dependent induction of c-fos mRNA was still present in cells treated for 3 h with cycloheximide, but it was greatly reduced by actinomycin D pretreatment. These data indicate that FSH induces a transient expression of c-fos in cultured Sertoli cells. This induction is probably mediated by cAMP and likely involves an increased transcription of the c-fos gene. Early expression of this gene might be an intermediate step required for gonadotropin-dependent regulation of expression of other genes.

Animals↗

PubMed1988

Molecular cloning of complementary deoxyribonucleic acid for an androgen-regulated epididymal protein: sequence homology with metalloproteins.

Acidic epididymal glycoprotein (AEG) is a 31,000 molecular weight secretory protein of the rat epididymis. Screening of a rat epididymal cDNA library with affinity-purified AEG antiserum yielded cDNA for AEG. Identity of the clones was verified by comparison of amino acid sequence of the purified protein with the sequence derived from the nucleotide sequence of the cDNA isolates. Two classes of AEG cDNA, approximately 1500 base pairs (bp) and 950 bp in length, differed by 538 bp in the 3'-untranslated region and by four single nucleotide mismatches, one of which was in the coding region. Northern blot hybridization of epididymal RNA revealed two species of AEG mRNA, corresponding in length to each type of cDNA. Analysis of RNA from individual animals provided evidence that the two mRNA species are the products of allelic genes. In vivo studies demonstrated that the level of total AEG mRNA is regulated by androgen. Amino acid sequence homology of AEG with metal-binding domains of several proteins suggests that AEG is a metalloprotein.

Amino Acid Sequence↗

PubMed1988

Antibodies to steroid receptor deoxyribonucleic acid binding domains and their reactivity with the human glucocorticoid receptor.

Functional properties of the DNA-binding domain of the human glucocorticoid receptor were investigated using high titer polyclonal antibodies produced against single synthetic peptides or a mixture of peptides whose sequences were derived from the DNA-binding domain of steroid receptor proteins. Three of seven antisera recognized both native and denatured forms of the glucocorticoid receptor, although considerably lower antisera dilutions were required for antibody binding to native receptor. Activation of the glucocorticoid receptor to its DNA-binding form was required for antibody recognition of the native receptor. Antisera to the second finger region of the DNA-binding domain caused a portion of the activated 4S glucocorticoid receptor to sediment as 7 or 9S in sucrose gradients containing 0.4 M KCl, but did not alter the sedimentation of the nontransformed 8S receptor. Specificity of the glucocorticoid receptor-antibody interaction was demonstrated by loss of reactivity after preabsorption with peptide antigens. Antisera that interacted specifically with the glucocorticoid receptor inhibited DNA binding of the activated receptor by as much as 80%. Thus, antibody probes directed against DNA-binding domain sequences provide immunological evidence that glucocorticoid receptor activation exposes the DNA-binding region of the receptor.

Amino Acid Sequence↗

PubMed1988

The human androgen receptor: complementary deoxyribonucleic acid cloning, sequence analysis and gene expression in prostate.

Androgenic hormones mediate their effects on male sex differentiation and development through a high affinity receptor protein. We report here cloning of the complete coding sequence of the human androgen receptor (hAR). By sequence homology hAR is a member of the nuclear receptor family, with closest sequence identity to the progesterone, mineralocorticoid, and glucocorticoid receptors. Regions of highest homology include the DNA-binding domain and a small region within the hydrophobic ligand-binding domain. Comparison of the deduced 919 amino acid sequence of hAR (98,999 mol wt) to the 902 amino acid sequence of rat AR (98,227 mol wt) reveals identical sequences in the DNA- and hormone-binding domains, with an overall homology of 85%. In human prostate, the major androgen receptor mRNA species is 10 kilobases while a less abundant mRNA is approximately 7 kilobases. Rabbit polyclonal antibodies were raised against a synthetic peptide from the N-terminal region of hAR. Immunocytochemical analysis of human prostate tissue demonstrated that AR is localized predominantly in nuclei of glandular epithelial cells.

Amino Acid Sequence↗

PubMed1988

The rat androgen receptor: primary structure, autoregulation of its messenger ribonucleic acid, and immunocytochemical localization of the receptor protein.

A composite androgen receptor DNA sequence 4,181 base pairs in length was determined from three cDNA clones isolated from a rat epididymal bacteriophage lambda gt11 library. An open reading frame of 902 amino acids encodes a protein of 98,227 mol wt. Structural domains characteristic of the steroid receptor family include an amino-terminal region with five repeated amino acid motifs, a central DNA-binding domain homologous with other steroid receptors, and a carboxyl-terminal steroid-binding region. A receptor cDNA probe used in Northern blot analysis hybridized with a predominant 10-kilobase androgen receptor mRNA in male reproductive tissues of the rat. Autoregulation of androgen receptor mRNA was indicated in rat ventral prostate by an increase in the level of 10-kilobase mRNA after castration and suppression of receptor mRNA upon androgen restimulation. A 15 amino acid peptide with sequence derived from the deduced androgen receptor sequence was synthesized and used as immunogen in raising receptor antibodies in rabbits. Antisera reacted with high titer against the synthetic peptide by enzyme-linked immunosorbent assay and against the native [3H]dihydrotestosterone-labeled androgen receptor as evidenced by an increase in receptor sedimentation rate determined by sucrose gradient centrifugation. Immunocytochemical staining localized the androgen receptor to epithelial cell nuclei in rat ventral prostate.

Amino Acid Sequence↗

PubMed1987

Vitamin K-dependent protein S is similar to rat androgen-binding protein.

Vitamin K-dependent protein S belongs to the family of clotting factors (e.g. Factors IX and X, and protein C). Unlike the other clotting factors, the C-terminal half (residues 250-634) of protein S is not a serine proteinase. In fact, the function of residues 250-634 of protein S is unknown. By using computer programs designed to detect evolutionary relationships between proteins, we find that this part of protein S is similar to rat androgen-binding protein, a protein produced and secreted by testicular Sertoli cells. The homology between protein S and androgen-binding protein suggests new approaches for elucidating their functions.

Amino Acid Sequence↗