Synthesis and assembly of infectious bovine papillomavirus particles in vitro

Bovine papillomavirus type 1 (BPV-1) virions were produced in vitro using vaccinia virus (VV) recombinants expressing the BPV-1 L1 and L2 capsid proteins. Particles morphologically resembling papillomaviruses were observed in the nucleus of cells infected with a VV recombinant for the BPV-1 L1 protein, and greater numbers of similar particles were seen in the nuclei of cells infected with a VV double recombinant for L1 and L2. Virus-like particles (VLPs) assembled in cells infected with the VV double recombinant for BPV-1 L1 and L2, and not those assembled in cells infected with the VV recombinant for BPV-1 L1 alone, were able to package BPV-1 DNA. Transcription of the BPV-1 E1 viral open reading frame was observed after a mouse fibroblast cell line was exposed to VLPs produced using a BPV-1 L1/L2 VV recombinant in a cell line containing episomal BPV-1 DNA. E1 transcription was not observed when the VLPs were pre-incubated with antibodies to the capsid protein of BPV-1. This system should allow an in vitro approach to the definition of the BPV-1 cellular receptor.

Functional consequences of a Na+ channel mutation causing hyperkalemic periodic paralysis

Hyperkalemic periodic paralysis (HYPP), one of several inheritable myotonic diseases, results from genetic defects in the human skeletal muscle Na+ channel. In some pedigrees, HYPP is correlated with a single base pair substitution resulting in a Met replacing Thr704 in the fifth transmembrane segment of the second domain. This region is totally conserved between the human and rat channels. We have introduced the human mutation into the corresponding region of the rat muscle Na+ channel cDNA and expressed it in human embryonic kidney 293 cells. Patch-clamp recordings show that this mutation shifts the voltage dependence of activation by 10-15 mV in the negative direction. The shift results in a persistent Na+ current that activates near -70 mV; this phenomenon could underlie the abnormal muscle activity observed in patients with HYPP.

Hyperkalemic periodic paralysis: rapid molecular diagnosis and relationship of genotype to phenotype in 12 families

We studied mutations of the adult voltage-gated skeletal muscle sodium channel gene in 12 families, from diverse ethnic backgrounds, with hyperkalemic periodic paralysis (HyperPP). We describe a novel procedure, using ligase chain reaction (LCR), to simultaneously identify two different point mutations (previously described) and one rare, apparently benign polymorphism that results in a nonconservative amino acid substitution. Three of 12 families showed the Met1592Val mutation, and six of 12 had the Thr704Met mutation. The mutation in three of the 12 families was not identified. In one of these three families, the disease was not linked to the adult voltage-gated sodium channel gene, suggesting the existence of a clinically similar but genetically distinct form of HyperPP. Genotype/phenotype correlations based on patient records and interviews in these families showed the variable and subjective nature of the illness, although the clinical distinctions between hyperkalemic periodic paralysis and paramyotonia congenita were reinforced by the molecular data.

Anatomical and developmental patterns of facilitative glucose transporter gene expression in the rat kidney

In situ hybridization was used to map cellular patterns of gene expression for facilitative glucose transporters (GTs) 1-5 in the developing and adult rat kidney. GT3 was not detected. GT1 mRNA was present in the proximal straight tubule (PST), distal nephron and collecting duct. GT2 mRNA was localized in both proximal convoluted and PST, while GT5 mRNA was detected only in the PST. GT4 mRNA and immunoreactivity were focally localized in the thick ascending limb of Henle's loop and were coexpressed with IGF-I. Thus, each of the four different isoforms demonstrated a distinct renal distribution, with GTs 1, 2, and 5 coexpressed in the PST. Renal GT1 and GT5 gene expression were unchanged throughout development, while GT2 was most abundant before weaning and GT4 was first detected after weaning. Only GT4 appeared to be hormonally regulated: It was decreased after hypophysectomy and increased after vasopressin treatment, but was not affected by 1 or 4 d of insulinopenic diabetes mellitus. The coexpression of GT4 and IGF-I in the thick ascending limb segment of the nephron suggests a novel autocrine/paracrine mechanism by which cells may control local fuel economy independently from that of the larger structure to which they belong and from the systemic hormonal milieu.

Signal transduction mediated by angiotensin II receptor subtypes expressed in rat renal mesangial cells

Recent evidence suggests that there are two classes of receptors for angiotensin II (AngII), AT1 which is sensitive to losartan (DuP753) and is G-protein coupled, and AT2 which is sensitive to both PD123319 and CGP42112A, and is non-G-protein coupled. In rat mesangial cells two subtypes of AT1 receptor could be distinguished, AT1A subtype is more sensitive to losartan whereas AT1B subtype is more sensitive to PD123319, but insensitive to CGP42112A. The present studies were designed to ascertain which receptor subtype mediates three AngII-induced physiologic functions in rat mesangial cells namely intracellular Ca2+ mobilization, adenylyl cyclase inhibition and protein synthesis as monitored via [3H]leucine incorporation. The rank order of potency for inhibition of AngII-induced [Ca(2+)]i mobilization and adenylyl cyclase regulation was PD123319 > or = losartan > CGP42112A. By contrast, losartan was quite effective at inhibiting protein synthesis (IC50 = 8 nM) while PD123319 was without effect. These findings are consistent with AngII mediated signal transduction through AT1A and AT1B sites for phospholipase C mediated [Ca(2+)]i mobilization and inhibition of adenylyl cyclase. On the other hand, AT1A receptors appear to exclusively mediate AngII-induced protein synthesis. These observations underscore the complexity of AngII mediated signal transduction in glomerular mesangium.

Anatomy of the human ovarian insulin-like growth factor system

In situ hybridization was used to map insulin-like growth factor (IGF) system gene expression in ovaries from an anencephalic infant and several young women. Growing oocytes in infant and mature ovaries expressed transcripts for IGF-I and IGF-II, respectively, and all oocytes expressed abundant IGF-I receptor transcripts, raising the possibility of autocrine IGF function in oocyte maturation. IGF-I mRNA was not detected in the mature ovary, but IGF-II mRNA was localized in follicular blood vessels and in granulosa cells (GC) and was especially abundant in the GC of atretic as opposed to young follicles. IGF-I receptor mRNA was abundant in GC of antral and atretic follicles, and was expressed at low levels in the thecal and interstitial compartments. IGF-binding protein (IGFBP) 1 mRNA was not detected, but IGFBPs 2-5 mRNAs each demonstrated a unique ovarian distribution. IGFBP2 mRNA was abundant in GC and thecal cells at all stages of development. IGFBP3 mRNA was detected only in the endothelium of ovarian blood vessels. IGFBP4 mRNA was also localized in endothelium, but in addition was present in stromal connective tissue and in GC of the one Graafian follicle detected in this study, but not consistently in atretic follicles. IGFBP5 mRNA was expressed by luminal or cumulus GC in virtually all follicles and was highly abundant in stromal interstitial cells of the mature ovary.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of tetrahydroberberine on ischemic and reperfused myocardium in rats

The effects of tetrahydroberberine (THB) on ischemic and reperfused myocardium were studied in comparison with verapamil (Ver). In anesthetized rats, THB and its analogues, l-THP and l-SPD, reduced the infarct size after 4 h of left anterior descending coronary artery (LAD) ligation. In Langendorff hearts, in common with Ver, THB 1 and 10 mumol.L-1 markedly decreased the incidences of ventricular tachycardia (VT) and ventricular fibrillation (VF) in the reperfusion period. The malondialdehyde content and xanthine oxidase activity were also decreased in global ischemic-reperfused hearts pretreated with THB (P < 0.01, or P < 0.05). It suggested that THB could protect the myocardium from ischemic and reperfusion injury.

Placental glucose transporter gene expression and metabolism in the rat

In situ hybridization was used to evaluate patterns of gene expression for glucose transporters 1-4 (GT1-4) in the rat uteroplacenta from the time of implantation through term, and in vivo regional placental glucose metabolism was measured by 14C-labeled 2-deoxyglucose uptake. GT1 mRNA was highly abundant and GT3 was barely detected in the postimplantation decidual reaction. GT1 and 3 mRNAs were colocalized in the labyrinthine syncitiotrophoblast layer of the chorioallantoic placenta, which forms the membranous barrier between maternal and fetal circulations. The level of labyrinthine GT3 mRNA showed no change from midgestation through term; however, the volume of the labyrinth and hence total GT 3 gene expression increased greatly during this period. Labyrinthine GT1 mRNA levels, in contrast, showed significant diminution near term. GT1 mRNA was also localized in the placental growth plate, or junctional zone, where it was most abundant during the period of rapid placental growth and was decreased at term. Placental glucose metabolism, as reflected by steady-state 2-deoxyglucose uptake, was highest in the junctional zone during the rapid growth phase during midgestation, and decreased significantly at term, in parallel with GT1 gene expression. These findings suggest that GT1 is responsible for supplying glucose for use as a placental fuel and that GT3 is important for glucose transfer to the embryo.

Mutations in the codon for a conserved arginine-1563 in the COL4A5 collagen gene in Alport syndrome

We have screened 110 unrelated Alport syndrome kindreds for mutations in the exon 48 region of the COL4A5 collagen gene. Denaturing gradient gel electrophoresis (DGGE) of the PCR-amplified region of exon 48 revealed sequence variants in DNA from affected males and carriers of three unrelated kindreds. All three kindreds have classical Alport syndrome of the juvenile type. DNA-sequencing analyses demonstrated two different single base changes in the codon for arginine-1563 located in exon 48. In Utah kindred 2103, there was a substitution of C by T resulting in the change of the CGA codon for arginine to the translation stop codon TGA. In Utah kindred 2123 and in the Danish kindred A13, there was a C-->T mutation in the noncoding strand changing the same codon to CAA for glutamine. Both mutations were confirmed by allele-specific hybridization on PCR-amplified DNA from other family members.

A system for monitoring temperature distribution in bed and its application to the assessment of body movement

For the assessment of body movements during sleep, a system for monitoring the temperature in bed was developed. The system consists of 16 temperature sensors and a data logger with a memory card. Fifteen of the temperature sensors were arranged in line 6 cm apart on a flat cable. The temperatures at these 15 points in the bed, and the room temperature measured by the additional sensor, were stored on the memory card at predetermined intervals. The data were transferred into a microcomputer and analysed. Changes in posture and body movement were recognizable from the changes in the temperature profile, and well visualized using a three-dimensional display of the successive temperature profiles in the bed. The time of body movement was estimated from the derivative of the temperature profile. Comparison between this estimation and the video recording showed good agreement. The linear arrangement of the sensors provides a high-resolution temperature profile during sleep.

COL4A5 splice site mutation and alpha 5(IV) collagen mRNA in Alport syndrome

Mutations affecting the COL4A5 gene encoding the alpha 5 chain of type IV collagen, are involved in the pathogenesis of X-linked Alport syndrome. We used denaturing gradient gel electrophoresis (DGGE) to screen PCR amplified exons of COL4A5 for point mutations in a set of 18 Alport patients previously characterized by Southern blotting. One sequence variant was identified in the exon 38 region of a male Alport patient. Sequence analysis revealed a G to C transversion in the 5' intron splice donor site downstream from exon 38 (GT to CT). To determine the effect of the mutation on mRNA splicing, alpha 5(IV) cDNA was generated from total RNA of peripheral blood lymphocytes. Subsequent cDNA PCR yielded a product 81 base pairs shorter in the affected Alport patient, compared to normal controls. The absence of exon 38 from the alpha 5(IV) cDNA was confirmed by sequence analysis. The results demonstrated that the mutation leads to skipping of exon 38 in the processing of alpha 5(IV) pre-mRNA. The shortened transcript lacked 27 codons encoding a Gly-X-Y-repeat sequence with a preserved reading frame, enabling the translation of codons further downstream. Clinically, the patient presented with juvenile onset Alport syndrome, end-stage renal failure, and deafness. He had no ocular lesions. Typical ultrastructural changes of the glomerular basement membrane (GBM) were shown on electron microscopy. The patient developed anti-GBM antibodies after renal transplantation, however, renal function deteriorated only moderately.

CD4-independent binding of HIV-1 to the B lymphocyte receptor CR2 (CD21) in the presence of complement and antibody

Complement and antibody contribute to infection-enhancement and possible expanded cellular tropism of HIV-1 in vitro through a process requiring complement receptors. Until now, however, the ability of HIV-1 to bind complement receptors has not been documented or characterized. We investigated whether antibody and complement permitted HIV-1 to bind to the B lymphocyte receptor, CR2 (CD21), in an effort to learn more about infection-enhancement, and also because CR2 can mediate B cell proliferation and antigen localization in lymphoid organs in other systems. HIV-1 incubated with antibody and fresh human serum as a source of complement bound approximately 10-fold greater to cells expressing CR2 than to HIV-1-permissive cells lacking this receptor. A similar effect was observed using cells which expressed CR2 but no CD4. This binding was minimal in heat-inactivated and C3-deficient sera, and was significantly reduced by the anti-CR2 MoAb, OKB7, but not by the anti-CD4 MoAb, OKT4a. Thus, complement and antibody acted in concert to facilitate the binding of HIV-1 to CR2 independently of CD4. CD4-independent binding of HIV-1 to CR2 was not sufficient to produce infection in Raji-3 cells. Titres of antibodies mediating CR2 binding correlated with antibody titres as measured by immunofluorescence (P < 0.01) and infection-enhancement (P < 0.05) but were discordant with titres of neutralizing antibodies, a result consistent with the utilization of CR2 for enhanced infection of cells. The ability of complement and antibody to facilitate the binding of HIV-1 to CR2 in the absence of CD4 provides new insights into mechanisms of HIV-1-induced immunopathogenesis and infection-enhancement.

CECIL: a database for storing and retrieving clinical and molecular information on patients with Alport syndrome

CECIL is a database that stores clinical and molecular information on patients with Alport syndrome. The clinical component of CECIL is specific to Alport syndrome; the component that stores and manipulates molecular data can be used for any disease caused by a gene mutation, such as cystic fibrosis. While offering the ability to retrieve patient data through compound Boolean queries, CECIL also offers the ability to manipulate sequence information in various ways. In particular, CECIL can perform an augmented sequence alignment of an abnormal (patient) DNA sequence with a reference sequence. CECIL is currently being used by members of the International Alport Syndrome consortium. We describe CECIL's features and discuss the design decisions made in generalizing CECIL's architecture.

Fibroblast growth factor inhibits proliferation of a highly tumorigenic insulin-independent teratoma-derived cell line

The present paper examines the effect of basic fibroblast growth factor (bFGF) on the proliferation of teratoma-derived cell lines having increased tumorigenic properties isolated from the non-tumorigenic adipogenic cell line 1246. Although FGF is a mitogen for the non tumorigenic 1246 cells and for the moderately tumorigenic 1246-3A cells derived from the 1246 cells, bFGF inhibits the proliferation and DNA synthesis of the highly tumorigenic PC cells starting at concentration as low as 30 pg/ml. The inhibitory effect of FGF on PC cell growth is irreversible as demonstrated by the inability of the cells to resume proliferation once FGF is removed from the culture medium. Comparison of 125I-bFGF binding to the three cell lines was performed. Based on the Scatchard analysis of the binding data, PC cells display only low affinity class of FGF binding sites whereas 1246 and 1246-3A cells presented also high affinity binding sites. The inhibitory effect of FGF on PC cells did not go through activation of a PKC mediated pathway, which is also known to inhibit PC cell proliferation, since FGF inhibition of PC cell growth was still apparent after PKC down regulation. FGF was still able to transiently stimulate the expression of mRNA for early growth associated genes as demonstrated by c-myc and c-fos expression, although it inhibited cell proliferation on PC cells. Our data demonstrate that the highly tumorigenic teratoma cells acquire an inhibitory response for a factor which is growth stimulatory to non-tumorigenic and moderately tumorigenic cells from which they are derived.

Molecular genetics of Alport syndrome

Alport syndrome is a progressive hereditary kidney disease characterized by hematuria, sensorineural hearing loss and ocular lesions with structural defects in the glomerular basement membrane (GBM). The gene frequency has been estimated to be 1:5000. The disease is primarily X chromosome-linked, but autosomal forms have also been reported. The X-linked form has been shown to be caused by mutations in a recently identified alpha 5(IV) collagen chain gene (COL4A5). We have isolated cDNA clones for providing the entire primary structure of the human alpha 5(IV) chain. The gene has been located to the Xq22 region. Using antibodies against synthetic peptides, the alpha 5(IV) chain was shown to be located in the kidney only in the glomerular basement membrane. Thus far, the exon-intron structure has been determined for a large portion of the gene which probably has a size of over 200 kb. Numerous different mutations have been identified in the COL4A5 gene. The mutations include single base mutations, large deletions and other major rearrangements such as inversion and duplication. The consequences of the mutations observed can be considered sufficient to cause structural and functional defects in the type IV collagen molecule and, therefore, also the GBM network. This, in turn can explain the disruption of the GBM and hematuria occurring in these Alport patients. Alport syndrome is the first genetic basement membrane and kidney disease whose gene has been cloned. These recent results have enabled the development of antibodies and DNA probes for accurate diagnosis of Alport syndrome.

FGF inactivates myogenic helix-loop-helix proteins through phosphorylation of a conserved protein kinase C site in their DNA-binding domains

Myogenin belongs to a family of myogenic helix-loop-helix (HLH) proteins that activate muscle transcription through binding to a conserved DNA sequence associated with numerous muscle-specific genes. Fibroblast growth factor (FGF) inhibits myogenesis by inactivating myogenic HLH proteins. We show that activated protein kinase C (PKC) can substitute for FGF and inhibit transcriptional activity of myogenic HLH proteins. In transfected cells, FGF induces phosphorylation of a conserved site in the DNA-binding domain of myogenin. This site is phosphorylated by PKC in vivo and in vitro and mediates repression of the myogenic program through a loss in DNA binding activity. A myogenin mutant lacking the PKC phosphorylation site is not repressed by FGF, confirming this site as a molecular target for FGF-dependent repression of muscle transcription. These results establish a direct link between the signal transduction pathways that inhibit myogenesis and the transcription factors directly activating muscle-specific genes.

Alport syndrome: a genetic study of 31 families

Thirty one families with Alport syndrome including 3 families with associated syndromes were studied. The location of the COL4A5 gene, responsible for the Alport syndrome, was determined by linkage analysis with eight probes of the Xq arm and by a radiation hybrid panel. Concordant data indicated the localization of the Alport gene between DXS17 and DXS11. Four deletions and one single base mutation of the COL4A5 gene were detected. Homogeneity tests failed to show any evidence of genetic heterogeneity superimposed on clinical heterogeneity for ophthalmic signs and end-stage renal disease age.

Deletions of the COL4A5 gene in patients with Alport syndrome

Mutations in the COL4A5 gene encoding the alpha 5 chain of type IV collagen have been found in linkage with X-chromosomal Alport syndrome (AS). To identify COL4A5 mutations in patients from Germany with clinically defined AS, DNA from 20 unrelated patients was analyzed by conventional Southern blotting. By using full length alpha 5(IV) cDNA probes, large COL4A5 deletions could be detected in two patients. In one case, a 34 kb deletion affecting the 14 most 3' exons of the gene was observed. The second patient harbored a complete COL4A5 deletion. In both cases, functional alpha 5(IV) mRNA was unlikely to be present. Clinically, both patients developed end-stage renal failure before age 30. Furthermore, they had characteristic retinal flecks, and sensorineural hearing loss with typical changes on the audiogram. The patient with the complete deletion of COL4A5 lost the renal allograft due to an anti-GBM mediated glomerulonephritis.

Renal growth hormone receptor gene expression: relationship to renal insulin-like growth factor system

In order to elucidate potential sites of direct GH action on the kidney, we used in situ hybridization to localize GH receptor (GHR) gene expression during the course of development and in the adult rat. In order to illuminate potential interactions between GH and insulin-like growth factor-I (IGF-I) in regulating renal function, we compared the anatomical localization of GHR messenger RNA (mRNA) with that for the IGF-I receptor and for IGF-I in the rat kidney. Low levels of GHR mRNA were present in the kidney from before birth and increased in abundance until postnatal day 40. Hypophysectomy resulted in a decrease and GH treatment resulted in an increase in renal GHR mRNA levels. Renal GHR mRNA was most abundant in the proximal straight tubule, with lesser levels present in the medullary thick ascending limb (MTAL), and it was not detected in the glomerulus or inner medulla. In contrast, IGF-I receptor mRNA was concentrated in the glomerulus, distal nephron and collecting system. The only point of convergence for GHR and IGF-I receptor mRNAs was in the MTAL, where IGF-I mRNA was localized. This segregation of GHR and IGF-I receptor gene expression in the kidney suggests that each hormone has distinct spheres of action along the nephron, with GH acting directly on the proximal straight tubule, whereas IGF-I may act on the glomerulus, distal nephron, and collecting duct. GHR expression in the MTAL, which is the site of renal IGF-I synthesis, supports the view that GH has a direct effect on renal IGF-I synthesis. Finally, it appears that in the kidney, as in other GH-sensitive tissues, GH may regulate its receptor levels.

Alport syndrome and diffuse leiomyomatosis: deletions in the 5' end of the COL4A5 collagen gene

Alport syndrome (AS) is an hereditary glomerulonephritis that is mainly inherited as a dominant X-linked trait. Structural abnormalities in the type IV collagen alpha 5 chain gene (COL4A5), which maps to Xq22, have recently been detected in several patients with AS. The association of AS with diffuse esophageal leiomyomatosis (DL) has been reported in 24 patients, most of them also suffering from congenital cataract. The mode of transmission and the location of the gene(s) involved in this association have not been elucidated. Southern blotting using cDNA probes spanning the whole COL4A5 and a 5' end COL4A5 genomic probe showed that three out of three patients with the DL-AS association had a deletion in the 5' part of the COL4A5 gene extending beyond its 5' end. This indicates that the same gene, COL4A5, is involved in classical AS and in DL-AS and that the transmission of DL-AS is X-linked dominant. These results also suggest that leiomyomatosis might be due to the alteration of a second gene involved in smooth muscle cell proliferation, which is located upstream of the COL4A5 gene, and that there might be a contiguous gene deletion syndrome, involving at least the genes coding for congenital cataract, DL and AS.

Isolation and characterization of two wound-regulated tomato extensin genes

Extensins comprise a family of structural cell wall hydroxyproline-rich glycoproteins in plants. Two tomato genomic clones, Tom J-10 and Tom L-4, were isolated from a tomato genomic DNA library by in situ plaque hybridization with extensin DNA probes. Tom J-10 encoded an extensin with 388 amino acid residues and a predicted molecular mass of 43 kDa. The Tom J-10 encoded extensin lacked a typical signal peptide sequence, but contained two distinct protein domains consisting of 19 tandem repeats of Ser-Pro4-Ser-Pro-Lys-Tyr-Val-Tyr-Lys at the amino terminus which were directly followed by 8 tandem repeats of the consensus sequence Ser-Pro4-Tyr3-Lys-Ser-Pro4-Ser-Pro at the carboxy terminus. RNA blot hybridization analysis with the Tom J-10 extensin probe demonstrated the presence of a 4.0 kb tomato stem mRNA which accumulated markedly in response to wounding. Tom L-4 encoded an extensin with 322 amino acid residues and a predicted molecular mass of 35 kDa. The Tom L-4 encoded extensin contained a typical signal peptide sequence at the amino terminus and was followed by at least 3 distinct domains. These domains consisted of an amino terminal domain containing several Lys-Pro and Ser-Pro4 repeat units, a central domain with repeats of the consensus sequence Ser-Pro2-5-Thr-Pro-Ser-Tyr-Glu-His-Pro-Lys-Thr-Pro, and a carboxy terminal domain containing repeats of the consensus sequence Ser-Ser-Pro4-Ser-Pro-Ser-Pro4-Thr-Tyr1-3. RNA blot hybridization analysis with the Tom L-4 extensin probe demonstrated the presence of a 2.6 kb tomato stem mRNA which accumulated in response to wounding.

Expression of c-erb B-2/neu proto-oncogene in human prostatic cancer tissues and cell lines

Both amplification and overexpression of c-erb B-2/neu have been associated with the progression and possible prognosis of a number of human cancers. In this study, we demonstrated that c-erb B-2/neu may also play an important role in human prostate cancer. Our conclusion is based on the following observations: (1) A monoclonal antibody raised against a peptide sequence from the C-terminal domain of the human c-erb B-2/neu gene product reacted positively with 68.7% (11 of 16) of the human prostatic cancer tissue extracts analyzed by western blot procedure. These results were supported by the immunohistochemical staining of the prostatic cancer specimens; 80% (12 of 15) showed positive staining, primarily around the plasma membranes of the prostatic cancer cells. c-erb B-2/neu oncoprotein was not detectable in normal prostate tissues (five examined by immunohistochemical staining and three by western blotting) or in human benign prostatic hyperplasia (two examined by immunohistochemical staining and six by western blotting) and was expressed less abundantly with lower intensity in "normal" human prostate tissues adjacent to cancerous prostate tissue (5 of 12 examined by immunohistochemical staining). We observed no evidence of c-erb B-2/neu gene amplification in 10 fresh human prostatic cancer specimens examined by Southern blotting and in the cultured human prostatic cancer cell lines PC-3, DU-145, and LNCaP. (2) The c-erb B-2/neu protein was detected in both androgen-receptor-positive (LNCaP) and -negative (PC-3 and DU-145) human prostate cancer cell lines. Positive immunostaining of c-erb B-2/neu protein was found to be associated predominantly with the plasma membranes of PC-3 cells, but was also found to be widespread in the cytoplasmic region of the LNCaP cells and in the perinuclear region of the DU-145 cells. (3) Like prostate-specific antigen (PSA) expression, c-erb B-2/neu mRNA expression was also positively regulated by androgen in androgen-receptor-positive LNCaP cells in vitro and LNCaP tumors in vivo. When LNCaP tumors were grown in castrated male hosts, levels of c-erb B-2/neu and PSA mRNA expression decreased initially, but rebounded at 3 wk to levels comparable to those expressed by tumors maintained in intact adult male hosts.

p140trk mRNA marks NGF-responsive forebrain neurons: evidence that trk gene expression is induced by NGF

Nerve growth factor (NGF) appears to act as a neurotrophic factor for basal forebrain and caudate-putamen cholinergic neurons. The mechanism by which NGF transduces its signal in these neurons is yet to be defined. Recent data indicate that the product of the trk gene, p140trk, is a critical component of the NGF receptor. Herein, we show that p140trk mRNA is highly restricted in its distribution in the adult rat forebrain, that it is present in cholinergic neurons, and that most if not all cholinergic neurons contain p140trk mRNA. Furthermore, induction of trk expression by NGF suggests that neurotrophin-mediated up-regulation of their receptor tyrosine kinases is an important feature of their actions and that neurotrophins may regulate the activity of responsive neurons through increasing the level of their receptors.