Localization and recycling of gp27 (hp24gamma3): complex formation with other p24 family members

We report here the characterization of gp27 (hp24gamma3), a glycoprotein of the p24 family of small and abundant transmembrane proteins of the secretory pathway. Immunoelectron and confocal scanning microscopy show that at steady state, gp27 localizes to the cis side of the Golgi apparatus. In addition, some gp27 was detected in COPI- and COPII-coated structures throughout the cytoplasm. This indicated cycling that was confirmed in three ways. First, 15 degrees C temperature treatment resulted in accumulation of gp27 in pre-Golgi structures colocalizing with anterograde cargo. Second, treatment with brefeldin A caused gp27 to relocate into peripheral structures positive for both KDEL receptor and COPII. Third, microinjection of a dominant negative mutant of Sar1p trapped gp27 in the endoplasmic reticulum (ER) by blocking ER export. Together, this shows that gp27 cycles extensively in the early secretory pathway. Immunoprecipitation and coexpression studies further revealed that a significant fraction of gp27 existed in a hetero-oligomeric complex. Three members of the p24 family, GMP25 (hp24alpha2), p24 (hp24beta1), and p23 (hp24delta1), coprecipitated in what appeared to be stochiometric amounts. This heterocomplex was specific. Immunoprecipitation of p26 (hp24gamma4) failed to coprecipitate GMP25, p24, or p23. Also, very little p26 was found coprecipitating with gp27. A functional requirement for complex formation was suggested at the level of ER export. Transiently expressed gp27 failed to leave the ER unless other p24 family proteins were coexpressed. Comparison of attached oligosaccharides showed that gp27 and GMP25 recycled differentially. Only a very minor portion of GMP25 displayed complex oligosaccharides. In contrast, all of gp27 showed modifications by medial and trans enzymes at steady state. We conclude from these data that a portion of gp27 exists as hetero-oligomeric complexes with GMP25, p24, and p23 and that these complexes are in dynamic equilibrium with individual p24 proteins to allow for differential recycling and distributions.

A family of mammalian proteins homologous to yeast Sec24p

The Sec23p/Sec24p complex is a component of yeast coat protein II (COPII), the coat protein complex responsible for vesicle budding from the endoplasmic reticulum (ER). Database searches and molecular cloning reveal that four different mammalian Sec24p-like proteins exist, all with about 20% amino acid identity with the yeast Sec24p. Sec24A and Sec24B share about 50% amino acid identity. Sec24D is cloned by screening a human pancreas of cDNA library with an expressed sequence tag (EST) fragment that is homologous to, but distinct from, Sec24A and Sec24B. Sec24D shares about 50% amino acid identity with the gene product of KIAA0079, which we have designated as Sec24C. These mammalian Sec24s appear to form two subclasses based on homology. Sec24A/B and Sec24C/D share about 20% identity with each other and with the yeast Sec24p. The Sec24 sequences also share weak but significant homology to the mammalian Sec23A and Sec23B. Northern blot analysis revealed that Sec24C is ubiquitously expressed. Although Sec24D transcripts are detectable in all tissues examined, they are selectively enriched in certain tissues, particularly placenta and pancreas. myc-tagged Sec24C and sec24D colocalized with Sec13, another COPII component. This colocalization suggests that Sec24C and Sec24D are indeed associated with COPII structures on membranes of the ER-Golgi boundary. The existence of at least four forms of Sec24 in mammalian cells suggest that multiple forms of COPII complex may be involved in ER export.

cDNA characterization and chromosomal mapping of human golgi SNARE GS27 and GS28 to chromosome 17

Transport of proteins along the exocytotic pathway is primarily achieved by vesicular intermediates. Two proteins, Golgi SNAREs of 27 kDa, GS27, and of 28 kDa, GS28 (HGMW-approved nomenclature GOSR2 and GOSR1, respectively), are important trafficking membrane proteins between the endoplasmic reticulum and the Golgi and between Golgi subcompartments. Here, we present the human GS27 and GS28 cDNA sequences. They encode predicted proteins of 212 and 250 amino acids, respectively. Chromosomal mapping analyses reveal that human GS27 is located on chromosome 17q21 and GS28 on approximately 17q11. The chromosomal location of GS27 near a locus implicated in familial essential hypertension and its known function in trafficking indicate that it is a potential candidate gene for this disease.

The reform of the rural cooperative medical system in the People's Republic of China: interim experience in 14 pilot counties

During the 1960's and 1970's the Chinese government encouraged the 'rural cooperative medical systems' (RCMS), in order to ensure access to basic health care among the rural population. There was a break in the development of the RCMS in the early 1980's, as a consequence of market economic reforms. These reforms involved a shift from a communal to a household production system. As a result the collective way of financing rural health care was more or less abandoned. However, the government of the People's Republic of China was aware of the need to provide social protection against health care expenses. In March 1994 the government initiated a project to reestablish the RCMS. This project was implemented on a pilot basis in 14 counties of seven provinces. The reestablishment of the RCMS would be guided by the basic principles of health insurance. In October 1995, a first mid-term evaluation of the RCMS Project was held. One of the major research questions concerned the extent to which the RCMS had reduced the risk of paying health care bills that would otherwise be a burden on families. This article addresses this question and assesses the results obtained after two years of RCMS experimental work. A general finding is that the population structure by occupation and income varies, and that the RCMS has adapted itself to this variety. It is also confirmed that the burden of health care costs on families was reduced, more so in some counties than in others, but this reduction has been modest. The research results indicate that there is ample room for improvement. The outlook is hopeful, however. At the national level, there is now systematic thinking about RCMS. The current RCMS work is also having a considerable influence on other counties that are keen to reestablish the RCMS.

Forward and retrograde trafficking in mitotic animal cells. ER-Golgi transport arrest restricts protein export from the ER into COPII-coated structures

Protein transport arrest occurs between the ER and Golgi stack of mitotic animal cells, but the location of this block is unknown. In this report we use the recycling intermediate compartment protein ERGIC 53/p58 and the plasma membrane protein CD8 to establish the site of transport arrest. Recycled ERGIC 53/p58 and newly synthesised CD8 accumulate in ER cisternae but not in COPII-coated export structures or more distal sites. During mitosis the tubulovesicular ER-related export sites were depleted of the COPII component Sec13p, as shown by immunoelectron microscopy, indicating that COPII budding structures are the target for mitotic inhibition. The extent of recycling of Golgi stack residents was also investigated. In this study we used oligosaccharide modifications on CD8 trapped in the ER of mitotic cells as a sensitive assay for recycling of Golgi stack enzymes. We find that modifications conferred by the Golgi stack-resident GalNac transferase do occur on newly synthesised CD8, but these modifications are entirely due to newly synthesised transferase rather than to enzyme recycled from the Golgi stack. Taken together our findings establish for the first time that the site of ER-Golgi transport arrest of mitotic cells is COPII budding structures, and they clearly speak against a role for recycling in partitioning of Golgi stack proteins via translocation to the ER.

Morphological and functional association of Sec22b/ERS-24 with the pre-Golgi intermediate compartment

Yeast Sec22p participates in both anterograde and retrograde vesicular transport between the endoplasmic reticulum (ER) and the Golgi apparatus by functioning as a v-SNARE (soluble N-ethylmaleimide-sensitive factor [NSF] attachment protein receptor) of transport vesicles. Three mammalian proteins homologous to Sec22p have been identified and are referred to as Sec22a, Sec22b/ERS-24, and Sec22c, respectively. The existence of three homologous proteins in mammalian cells calls for detailed cell biological and functional examinations of each individual protein. The epitope-tagged forms of all three proteins have been shown to be primarily associated with the ER, although functional examination has not been carefully performed for any one of them. In this study, using antibodies specific for Sec22b/ERS-24, it is revealed that endogenous Sec22b/ERS-24 is associated with vesicular structures in both the perinuclear Golgi and peripheral regions. Colabeling experiments for Sec22b/ERS-24 with Golgi mannosidase II, the KDEL receptor, and the envelope glycoprotein G (VSVG) of vesicular stomatitis virus (VSV) en route from the ER to the Golgi under normal, brefeldin A, or nocodazole-treated cells suggest that Sec22b/ERS-24 is enriched in the pre-Golgi intermediate compartment (IC). In a well-established semi-intact cell system that reconstitutes transport from the ER to the Golgi, transport of VSVG is inhibited by antibodies against Sec22b/ERS-24. EGTA is known to inhibit ER-Golgi transport at a stage after vesicle/transport intermediate docking but before the actual fusion event. Antibodies against Sec22b/ERS-24 inhibit ER-Golgi transport only when they are added before the EGTA-sensitive stage. Transport of VSVG accumulated in pre-Golgi IC by incubation at 15 degreesC is also inhibited by Sec22b/ERS-24 antibodies. Morphologically, VSVG is transported from the ER to the Golgi apparatus via vesicular intermediates that scatter in the peripheral as well as the Golgi regions. In the presence of antibodies against Sec22b/ERS-24, VSVG is seen to accumulate in these intermediates, suggesting that Sec22b/ERS-24 functions at the level of the IC in ER-Golgi transport.

[Expression of adhesion molecules beta 1 integrin on the surface of fibroblasts in wound healing]

OBJECTIVE

To investigate the relationship between the expression of adhesion molecules integrin beta 1 and the synthesis of collagen in wound healing.

METHODS

In this study, integrin beta 1 expression on fibroblasts derived from granulated wound and from normal skin was compared by the technique of immunoelectron microscope and flow cytometry. The differences of ultrastructure between the two groups of fibroblasts were also observed.

RESULTS

The results showed that the expression of alpha 5 and beta 1 subunits on fibroblasts derived from granulated wound were higher than those from normal skin. Endoplasmic reticulum attached with more ribosome in the former cells was richer than that in the latter cells.

CONCLUSION

These results suggest that the expression of adhesion molecules integrin beta 1 appears to be associated with the synthesis of collagen in wound healing.

GS32, a novel Golgi SNARE of 32 kDa, interacts preferentially with syntaxin 6

Syntaxin 1, synaptobrevins or vesicle-associated membrane proteins, and the synaptosome-associated protein of 25 kDa (SNAP-25) are key molecules involved in the docking and fusion of synaptic vesicles with the presynaptic membrane. We report here the molecular, cell biological, and biochemical characterization of a 32-kDa protein homologous to both SNAP-25 (20% amino acid sequence identity) and the recently identified SNAP-23 (19% amino acid sequence identity). Northern blot analysis shows that the mRNA for this protein is widely expressed. Polyclonal antibodies against this protein detect a 32-kDa protein present in both cytosol and membrane fractions. The membrane-bound form of this protein is revealed to be primarily localized to the Golgi apparatus by indirect immunofluorescence microscopy, a finding that is further established by electron microscopy immunogold labeling showing that this protein is present in tubular-vesicular structures of the Golgi apparatus. Biochemical characterizations establish that this protein behaves like a SNAP receptor and is thus named Golgi SNARE of 32 kDa (GS32). GS32 in the Golgi extract is preferentially retained by the immobilized GST-syntaxin 6 fusion protein. The coimmunoprecipitation of syntaxin 6 but not syntaxin 5 or GS28 from the Golgi extract by antibodies against GS32 further sustains the preferential interaction of GS32 with Golgi syntaxin 6.

The recycling pathway of protein ERGIC-53 and dynamics of the ER-Golgi intermediate compartment

To establish recycling routes in the early secretory pathway we have studied the recycling of the ER-Golgi intermediate compartment (ERGIC) marker ERGIC-53 in HepG2 cells. Immunofluorescence microscopy showed progressive concentration of ERGIC-53 in the Golgi area at 15 degreesC. Upon rewarming to 37 degreesC ERGIC-53 redistributed into the cell periphery often via tubular processes that largely excluded anterograde transported albumin. Immunogold labeling of cells cultured at 37 degreesC revealed ERGIC-53 predominantly in characteristic beta-COP-positive tubulo-vesicular clusters both near the Golgi apparatus and in the cell periphery. Concentration of ERGIC-53 at 15 degreesC resulted from both accumulation of ERGIC-53 in the ERGIC and movement of ERGIC membranes closer to the Golgi apparatus. Upon rewarming to 37 degreesC the labeling of ERGIC-53 in the ERGIC rapidly returned to normal levels whereas ERGIC-53's labeling in the cis-Golgi was unchanged. Temperature manipulations had no effect on the average number of ERGIC-53 clusters. Density gradient centrifugation indicated that the surplus ERGIC-53 accumulating in the ERGIC at 15 degreesC was rapidly transported to the ER upon rewarming. These results suggest that the ERGIC is a dynamic membrane system composed of a constant average number of clusters and that the major recycling pathway of ERGIC-53 bypasses the Golgi apparatus.

[Thyroid cancer during pregnancy]

OBJECTIVE

To study the diagnosis and treatment of thyroid cancer during pregnancy.

METHOD

12 pregnant patients with thyroid cancer were retrospectively analysed.

RESULT

Diagnosis was dependent on the clinical manifestation, the examination of B-ultrasonic and the fine-needle aspiration biopsy of thyroid, 4 patients who asked for ending pregnancy were operated on after abortion, 6 patients with early and middle pregnancy were operated on during pregnancy, and 2 patients with late pregnancy were operated on after delivery. No patients showed recurrence of cancer, and their children were healthy, and the shape and function of the children's thyroid were normal.

CONCLUSION

Pregnant patients with thyroid cancer during early and middle pregnancy should be operated on in time, and late pregnant patients should be operated on after delivery. All patients should take levothyroxine.

Protein transport from the endoplasmic reticulum to the Golgi apparatus

As the first step of protein transport along the biosynthetic (secretory/exocytotic) pathway, transport from the endoplasmic reticulum (ER) to the Golgi apparatus has received much attention over the past several decades. The general structural organization underlying this transport process is becoming more defined. The major protein components participating in the budding, pre-docking, and docking/fusion events have been identified and their mechanistic aspects investigated. Conceptually, it is now clear that protein export from the ER is a selective process. Although much remains to be defined or refined, the general picture of this transport step has now emerged.

Gos1p, a Saccharomyces cerevisiae SNARE protein involved in Golgi transport

Specific transport between secretory compartments requires that vesicular carriers contain targeting proteins known as SNAREs. Ten v-SNAREs have been identified in the genome of the yeast Saccharomyces cerevisiae by sequence analysis. We report here the characterization of Gos1p, a v-SNARE localized to the Golgi compartment and likely homolog of the mammalian protein GOS-28/GS28. Gos1p is a type II membrane protein with characteristic SNARE sequence hallmarks and is functionally a SNARE protein. Gos1p was originally identified as a 28 kDa protein in an immunoprecipitate of the cis-Golgi t-SNARE Sed5p. This interaction between Sed5p and Gos1p is direct as demonstrated by in vitro binding with recombinant proteins. Deletion of GOS1 results in viable haploids with modest growth and secretory defects. Close examination of the secretory phenotype of GOS1-disrupted cells suggests that Gos1p may play a role in multiple transport steps, specifically ER-Golgi and/or intra-Golgi transport.

A novel synaptobrevin/VAMP homologous protein (VAMP5) is increased during in vitro myogenesis and present in the plasma membrane

cDNA clones encoding a novel protein (VAMP5) homologous to synaptobrevins/VAMPs are detected during database searches. The predicted 102-amino acid VAMP5 harbors a 23-residue hydrophobic region near the carboxyl terminus and exhibits an overall amino acid identity of 33% with synaptobrevin/VAMP1 and 2 and cellubrevin. Northern blot analysis reveals that the mRNA for VAMP5 is preferentially expressed in the skeletal muscle and heart, whereas significantly lower levels are detected in several other tissues but not in the brain. During in vitro differentiation (myogenesis) of C2C12 myoblasts into myotubes, the mRNA level for VAMP5 is increased approximately 8- to 10-fold. Immunoblot analysis using antibodies specific for VAMP5 shows that the protein levels are also elevated approximately 6-fold during in vitro myogenesis of C2C12 cells. Indirect immunofluorescence microscopy and immunoelectron microscopy reveal that VAMP5 is associated with the plasma membrane as well as intracellular perinuclear and peripheral vesicular structures of myotubes. Epitope-tagged versions of VAMP5 are similarly targeted to the plasma membrane.

[The clinical features and management of borderline ovarian tumors]

OBJECTIVE

To study the clinical features and management of borderline ovarian tumor (BOT).

METHODS

Retrospectively study 70 cases of BOT.

RESULTS

Age 16-76 years old, average 45.6 year old; histological type: mucinous 46(65.7%), serous 21(30%); stage: I 46 (65.7%), II 1(1.4%), III 11(15.7%), IV 0%, relapse 12(17.1%). Tumor marker: elevated CA125 11/21, carcinoembryonic antigen (CEA) 6/10.

TREATMENT

all patients were operated, 45 were given adjuvant therapy.

OUTCOME

No evidence of disease (NED) 45, with evidence of disease (WED) 4, died of disease (DOD) 11, died of intercurrent disease (DID) 10. 11 patients who were given conservative surgery were NED, there were 2 long term CR among 16 patients with residual disease who were given adjuvant treatment. The 5, 10, 20 and 30-year survival is 90.0%, 87.1%, 87.1% and 85.6% respectively. COX hazard regression model analysis showed that histological type (r = 24.825), stage (r = 2.236) and residual disease (r = 2.083) were the main factors which impact on the prognosis of BOT.

CONCLUSIONS

(1) The proportion of mucinous tumor is higher than that of serous tumor in this group; (2) Surgery is the proved only effective treatment of BOT till now, without any residual disease is expected; (3) Adjuvant therapy can't improve the prognosis of BOT; (4) CA125 and CEA can be two effective tumor markers in monitoring of BOT.

[Diagnostic evaluation of magnetic resonance urography in urinary tract dilatation and obstruction]

OBJECTIVE

To evaluate the diagnostic value of magnetic resonance urography (MRU).

METHODS

Two hundred and one patients were examined, 92 patients with urinary tract dilatation using a modified, heavily T2-weighted fast spin-echo pulse sequence and fat-suppression pulse aid. Postprocedure processing was performed with a maximum-intensity-projection (MIP) algorithm.

RESULTS

In the 92 patients with urinary tract dilatation, 86 had obstructive urinary tract dilatation 6 non-obstructive urinary tract dilatation. In the 86 patients, 14 had ureteral carcinoma, 19 calculus, and 13 benign stricture, 23 congenital ureteral stricture/or with anomalies, 7 ureteral obstructive caused by extrinsic pelvis disease, and 10 bladder carcinoma involved ureter. In the 6 patients, 5 had nervous bladder. MR urography provided the high-resolution image of the urinary tract and determined the presence of obstruction.

CONCLUSION

MR urography is a reliable noninvasive method for depicting the urinary tract.

Alpha-SNAP but not gamma-SNAP is required for ER-Golgi transport after vesicle budding and the Rab1-requiring step but before the EGTA-sensitive step

N-ethylmaleimide-sensitive factor (NSF) and soluble NSF attachment proteins (SNAPs) have been implicated in diverse vesicular transport events; yet their exact role and site of action remain to be established. Using an established in vitro system, we show that antibodies against alpha-SNAP inhibit vesicle transport from the ER to the cis-Golgi and that recombinant alpha-SNAP enhances/stimulates the process. Cytosol immunodepleted of alpha-SNAP does not support normal transport unless supplemented with recombinant alpha-SNAP but not gamma-SNAP. In marked contrast, cytosol immunodepleted of gamma-SNAP supports ER-Golgi transport to the normal level. Neither antibodies against gamma-SNAP nor recombinant gamma-SNAP have any effect on ER-Golgi transport. These results clearly establish an essential role for alpha-SNAP but not gamma-SNAP in ER-Golgi transport. When the transport assay is performed with cytosol immunodepleted of alpha-SNAP, followed by incubation with cytosol immunodepleted of a COPII subunit, normal transport is achieved. In marked contrast, no transport is detected when the assay is first performed with cytosol depleted of the COPII subunit followed by alpha-SNAP-depleted cytosol, suggesting that alpha-SNAP is required after a step that requires COPII (the budding step). In combination with cytosol immunodepleted of Rab1, it is seen that alpha-SNAP is required after a Rab1-requiring step. It has been shown previously that EGTA blocks ER-Golgi transport at a step after vesicle docking but before fusion and we show here that alpha-SNAP acts before the step that is blocked by EGTA. Our results suggest that alpha-SNAP may be involved in the pre-docking or docking but not the fusion process.

A 29-kilodalton Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptor (Vti1-rp2) implicated in protein trafficking in the secretory pathway

Expressed sequence tags coding for a potential SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) were revealed during data base searches. The deduced amino acid sequence of the complete coding region predicts a 217-residue protein with a COOH-terminal hydrophobic membrane anchor. Affinity-purified antibodies raised against the cytoplasmic region of this protein specifically detect a 29-kilodalton integral membrane protein enriched in the Golgi membrane. Indirect immunofluorescence microscopy reveals that this protein is mainly associated with the Golgi apparatus. When detergent extracts of the Golgi membrane are incubated with immobilized glutathione S-transferase alpha soluble N-ethylmaleimide-sensitive factor attachment protein (GST-alpha-SNAP), this protein was specifically retained. This protein has been independently identified and termed Vti1-rp2, and it is homologous to Vti1p, a yeast Golgi SNARE. We further show that Vti1-rp2 can be qualitatively coimmunoprecipitated with Golgi syntaxin 5 and syntaxin 6, suggesting that Vti1-rp2 exists in at least two distinct Golgi SNARE complexes. In cells microinjected with antibodies against Vti1-rp2, transport of the envelope protein (G-protein) of vesicular stomatitis virus from the endoplasmic reticulum to the plasma membrane was specifically arrested at the Golgi apparatus, providing further evidence for functional importance of Vti1-rp2 in protein trafficking in the secretory pathway.

Molecular analysis of Ewing's sarcoma: another fusion gene, EWS-E1AF, available for diagnosis

Ewing's sarcoma, one of the most malignant tumors of children and young adults, expresses specific chimeric genes, e.g. EWS-FLI-1, EWS-ERG, EWS-ETV1 and EWS-FEV. In this paper, we extensively characterized a new fusion gene, EWS-EIAF by means of whole cDNA sequencing, RNA blot analysis, DNA blot analysis and chromosomal analysis, and showed it to be available for the diagnosis of Ewing's sarcoma and to participate in the oncogenesis of Ewing's sarcoma. Furthermore, we conducted a genetic analysis of Ewing family tumors in conjunction with immunohistochemical analysis and ultrastructural analysis. Our results demonstrate some limitations of both genetic analysis and histopathological analysis, and establish the relationship between neurogenic phenotypes and chimera genes.

Endobrevin, a novel synaptobrevin/VAMP-like protein preferentially associated with the early endosome

Synaptobrevins/vesicle-associated membrane proteins (VAMPs) together with syntaxins and a synaptosome-associated protein of 25 kDa (SNAP-25) are the main components of a protein complex involved in the docking and/or fusion of synaptic vesicles with the presynaptic membrane. We report here the molecular, biochemical, and cell biological characterization of a novel member of the synaptobrevin/VAMP family. The amino acid sequence of endobrevin has 32, 33, and 31% identity to those of synaptobrevin/VAMP-1, synaptobrevin/VAMP-2, and cellubrevin, respectively. Membrane fractionation studies demonstrate that endobrevin is enriched in membrane fractions that are also enriched in the asialoglycoprotein receptor. Indirect immunofluorescence microscopy establishes that endobrevin is primarily associated with the perinuclear vesicular structures of the early endocytic compartment. The preferential association of endobrevin with the early endosome was further established by electron microscopy (EM) immunogold labeling. In vitro binding assays show that endobrevin interacts with immobilized recombinant alpha-SNAP fused to glutathione S-transferase (GST). Our results highlight the general importance of members of the synaptobrevin/VAMP protein family in membrane traffic and provide new avenues for future functional and mechanistic studies of this protein as well as the endocytotic pathway.

A single plasmid vector (pSTAR) mediating efficient tetracycline-induced gene expression

A plasmid vector (pSTAR) has been constructed which confers neomycin resistance for selecting stably transfected cells, possesses a cloning cassette for placing a gene of interest under the control of the tetO DNA motif, and expresses rtTAnls which, upon association with tetracycline, binds to and drives gene expression from the tetO DNA motif. The plasmid pSTAR/LacZ, which has the gene for beta-galactosidase inserted into the cloning cassette, was transfected into Chinese hamster ovary (CHO) cells and selected for stably transfected cells. In pooled transfectants of CHO, tetracycline induced the expression of beta-galactosidase in 10-30% of cells. Using clonal transfectants, beta-galactosidase expression was induced by tetracycline in essentially every cell. Furthermore, induction of beta-galactosidase expression by tetracycline was both dose- and time-dependent. Similar tetracycline-induced beta-galactosidase expression is also observed in other cell types. The pSTAR vector is thus suited to facilitate the application of tetracycline-induced gene expression in diverse research areas.

Syntaxin 11: a member of the syntaxin family without a carboxyl terminal transmembrane domain

We have cloned a novel syntaxin-like molecule, designated human syntaxin 11 (hsyn11). The open reading frame encodes a polypeptide of 287 amino acids with potential coiled-coil domains. hsyn11 has extensive homology to members of the syntaxin family, particularly syntaxin 1 and syntaxin 2. Unlike other members of the syntaxin family, however, hsyn11 has a short cysteinerich carboxyl-terminal tail but not a typical hydrophobic domain which may serve as a membrane anchor. Northern blot analysis revealed two transcripts of approximately 0.8 kb and approximately 1.7 kb in length that are particularly abundant in heart and placenta, although lower levels were also detectable in other tissues except in the brain. Consistent with the lack of a distinct membrane anchorage sequence in hsyn11, indirect immunofluorescence microscopy of transiently expressed N-terminally myc-tagged hsyn11 revealed a diffuse, cytoplasmic labeling.

Syntaxin 12, a member of the syntaxin family localized to the endosome

We have cloned a new member of the syntaxin family of proteins. The open reading frame encodes a polypeptide of 272 amino acids with potential coiled-coil domains and a C-terminal hydrophobic tail. Northern blot analysis showed that the transcript is fairly ubiquitous. A soluble recombinant form of the polypeptide without the hydrophobic region binds to alpha-SNAP (soluble N-ethylmaleimide-sensitive factor attachment protein) and syndet/SNAP-23 in vitro. Polyclonal antibody raised against the recombinant protein recognized a 39-kDa protein in the membrane fraction of cell lysates. Indirect immunofluorescence studies using the polyclonal antibody showed that the protein is localized to intracellular membrane structures. Selective permeabilization studies with digitonin and saponin indicate that the epitope(s) recognized by the antibody is expose to the cytoplasm, consistent with the predicted orientation characteristic of SNAP receptor molecules. Morphological alterations of the staining pattern of the protein with brefeldin A and wortmannin treatment indicate that the protein is localize to the endosome. The cDNA we have cloned apparently corresponded to three previously described expressed sequence tags named as syntaxins 12, 13, and 14, respectively. We therefore propose to retain the name syntaxin 12 for this protein.

Mouse PRL-2 and PRL-3, two potentially prenylated protein tyrosine phosphatases homologous to PRL-1

Protein tyrosine phosphatases (PTPs) play a fundamental role in regulating diverse cellular processes. PRL-1 is a unique nuclear PTP that is induced in mitogen-stimulated cells and regenerating liver. Database searches using the PRL-1 sequence led to the identification of mouse PRL-2 and PRL-3 which exhibit 87% and 76% identity to mouse PRL-1 in their amino acid sequences. All three mouse PRL proteins contain a C-terminal consensus sequence for prenylation. All PRL proteins bear significant sequence homology to Cdc14p and the recently identified tumor suppressor PTEN/MMAC1, in regions other than the conserved PTP signature motif. The nucleotide sequences of the coding regions of mouse PRL-2 and PRL-3 are, respectively, 71% and 62%, identical to mouse PRL-1, while the 5' un-translated regions of mouse PRL-1, PRL-2, and PRL-3 are much more divergent. Northern blot analysis revealed that PRL-2 is preferentially expressed in skeletal muscle, while PRL-3 is preferentially expressed in both skeletal muscle and heart, although both PRL-2 and PRL-3 are expressed at lower levels in other tissues.

[Detection of human cytomegalovirus infection in pregnant women and their fetuses by nested polymerase chain reaction]

OBJECTIVES

To evaluate the applicability of nested polymerase chain reaction (PCR) and restriction endonucleases analyses (REA) for the diagnosis of human cytomegalovirus (HCMV) in pregnant women and their fetuses.

METHODS

Nested PCR and REA, virus isolation, anti-HCMV-IgM and anti-HCMV-IgA were used for detection of HCMV in peripheral blood of pregnant women, umbilical blood and tissues of stillbirths.

RESULTS

Among 367 pregnant women, the HCMV infections rate in the first, second and third trimester of gestation were 8.6%, 1.6% and 7.0%, respectively. The nested PCR had significantly higher detective rate (4.9%) than that of virus isolation (3.0%, P < 0.025). Among 6 samples of maternal HCMV DNA positive blood, 3 matched umbilical samples were HCMV DNA positive as well. Of these 3 cases, HCMV intrauterine infection was considered. HCMV was detected with all measurements in both maternal and umbilical blood except in 1 paired samples specific-IgM were negative. HCMV DNA was found in the lung tissue of one of the 28 stillbirds.

CONCLUSION

The diagnostic specificity and sensitivity of HCMV can be raised by nested PCR.

[Treatment of malignant germ cell tumors of the ovary: a clinical analysis of 233 cases]

OBJECTIVE

To evaluate the treatment methods of malignant germ cell tumors of the ovary.

METHODS

Two hundred thirty three patients with malignant germ cell tumors of the ovary treated during 1958 through 1993 were retrospectively analyzed. The number of patients in different stage of the disease was as follows: stage I, 94; stage II-IV, 43; recurrence or metastasis, 96. Unilateral salpingo-oophorectomy was performed in 78 patients, or total abdominal hysterectomy and bilateral salpingo-oophorectomy with or without omentectomy and appendectomy was performed in 151 cases, and biopsy in 4 cases. Operation alone was done in 17 cases, operation plus radiotherapy with or without chemotherapy in 65, operation plus chemotherapy in 151 cases.

RESULTS

Of the 233 patients 127 were disease-free. The number of survivors in stage I patients was 78, in stage II-IV was 17. There were 32 cases with recurrence and metastasis. The overall 5-year survival rate was 55.6%. The 5-year survival rate differed between dysgerminoma and nondysgerminomatous tumurs being 84.2% for the former and 44.6% for the latter. In patients with nondysgerminomatous tumors, chemotherapy with PVB and BEP regimens gave a 5-year survival rate of 66.0% and 73.3%, respectively.

CONCLUSION

Malignant germ cell tumors of the ovary is very sensitive to chemotherapy. The PVB and BEP regimens result in excellent response in these patients. Complete remission and preservation of fertility can be obtained in patients with early tumors. Preoperative chemotherapy and postoperative adjuvant chemotherapy can improve survival in patients with advanced tumors.

Hsec22c: a homolog of yeast Sec22p and mammalian rsec22a and msec22b/ERS-24

We have cloned a new member of a family of mammalian proteins homologous to Sec22p, a v-SNARE in Saccharomyces cerevisiae required for transport between the endoplasmic reticulum (ER) and the Golgi apparatus. The open reading frame encodes a polypeptide of 250 amino acids which is homologous to, but obviously different from, the recently reported mammalian Sec22p homologs rat sec22a, mouse sec22b, and hamster ERS-24. Northern blot analysis revealed two transcripts of about 1 and 5 kb respectively which are ubiquitously expressed. myc-epitope tagged sec22c is localized to the ER. Overexpression of the myc-tagged protein resulted in an anomalous staining pattern of SNARE molecules participating in ER-Golgi transport such as syntaxin 5 and mammalian bet1, but not the endosomal SNARE syntaxin 7. The presence of multiple forms of sec22 protein in the mammalian early secretory pathway is in-line with task specification in a highly elaborate transport machinery.

Molecular cloning and localization of human syntaxin 16, a member of the syntaxin family of SNARE proteins

We have cloned a new member of the syntaxin family of proteins, designated human syntaxin 16 (hsyn16). The open reading frame encodes a polypeptide of 307 amino acids with potential coiled-coil domains and a carboxy-terminal hydrophobic tail, which is characteristic of other members of the syntaxin family. The encoded polypeptide bears sequence homology to known syntaxin molecules. Northern blot analysis revealed a single transcript that is fairly ubiquitous, being slightly more enriched in heart and pancreas. Indirect immunofluorescence localised myc-tagged hsyn16 (myc-hsyn16) to the Golgi apparatus, colocalizing well with lens culinaris agglutinin, an established Golgi marker, as well as with other Golgi SNAREs such as GS28 and syntaxin 5. Myc-hsyn16 is redistributed to the endoplasmic reticulum upon brefeldin A treatment, indicating that it is localised to the Golgi stack. The ubiquitous expression and Golgi localization of hsy16 suggest that it is involved in a vesicular transport step within the organelle.

Syntaxin 10: a member of the syntaxin family localized to the trans-Golgi network

We have cloned a new member of the syntaxin family of proteins, designated human syntaxin 10 (hsyn10). The open reading frame encodes a polypeptide of 249 amino acids with potential coiled-coil domains and a carboxy-terminal hydrophobic tail. hsyn10 is particularly homologous to the recently reported rat syntaxin 6 (about 60% identity). Northern blot analysis showed that the transcript is enriched in the heart, skeletal muscles and pancreas. Indirect immunofluorescence studies using polyclonal antibodies raised against recombinant protein showed that the protein is localized to intracellular membrane structures, with perinuclear staining patterns colocalising well with the Golgi SNARE GS28. Morphological alterations of the staining pattern of the protein with brefeldin A but not wortmannin treatment indicate that the protein is localize to the trans-Golgi network.

Syntaxin 7, a novel syntaxin member associated with the early endosomal compartment

Members of the syntaxin family are key molecules involved in diverse vesicle docking/fusion events. We report here the molecular, biochemical, and cell biological characterizations of a novel member (syntaxin 7) of the syntaxin family. Syntaxin 7 is structurally related to all known syntaxins. Within a 79-residue region preceding the C-terminal hydrophobic tail, syntaxin 7 is 35, 34, 34, 34, 25, and 19% identical to syntaxins 1, 2, 3, 4, 5, and 6, respectively. Northern blot analysis showed that syntaxin 7 is widely expressed. Indirect immunofluorescence microscopy revealed that syntaxin 7 is primarily associated with the early endosome. In vitro binding assays established that syntaxin 7 in membrane extracts interacts with immobilized recombinant alpha-soluble N-ethylmaleimide-sensitive factor attachment proteins fused to glutathione S-transferase. Our results highlight the general importance of members of the syntaxin family in protein trafficking and provide new avenues for future functional and mechanistic studies of this first endosomal syntaxin as well as the endocytotic pathway.

Inhibins, activins, and follistatins: expression of mRNAs and cellular localization in tissues from men with benign prostatic hyperplasia

BACKGROUND

The transforming growth factor beta (TGF beta) superfamily of growth factors includes activins and inhibins, which have been shown to be present in the rat ventral prostate, and human prostate tumor cell lines, although their localization in benign prostatic hyperplasia (BPH) tissue is currently unknown.

METHODS

BPH tissues were obtained at surgery, and the mRNA expression for the inhibin alpha, beta A, beta B subunits, the putative activin beta C subunit, the activin type II receptor (ActRII), and the activin binding protein, follistatin, was determined by reverse transcription polymerase chain reaction (RT-PCR) and Southern blot analysis. Antibodies specific for alpha, beta A, beta B, activin A, and follistatin were used to determine the localization of these proteins in BPH tissue specimens.

RESULTS

Southern blot analysis confirmed that mRNA for ActRII, beta C subunit, and follistatin was present in all biopsy samples assayed. However, alpha, beta A, and beta B subunit mRNA expression was variable between patient samples. Immunohistochemistry demonstrated the predominant localization of beta A, beta B, and activin A proteins to the epithelium of BPH tissues. No immunoreactivity for the inhibin alpha subunit was detected; follistatin immunoreactivity was localized to the fibroblastic stroma.

CONCLUSIONS

The compartmentalization of activin subunit proteins to the epithelium, and of follistatin to the stroma, suggests that a paracrine interaction occurs between the activin ligands and follistatin-binding proteins in BPH tissue.

[Treatment of 129 patients with advanced and recurrent malignant ovarian germ cell tumor]

OBJECTIVE

To investigate the improved treatment for advanced malignant germ cell tumors of the ovary.

METHODS

129 patients with advanced and recurrent germ cell tumor of the ovary treated from 1958 to 1993 were retrospectively analyzed. The results of malignant nondysgerminomatous germ cell tumor of the ovary treated from 1958-1983 were compared with those treated with the supplement of VAC (Vincristine + ActinomycinD + Cyclophosphamide), PVB (Cisplatin + Vinblastine + Bleomycin) or BEP (Bleomycin + Etoposide + Cisplatin) combined chemotherapy from 1984-1993.

RESULTS

The overall 5-year survival rate was 30% (39/129) of advanced and recurrent germ cell tumor of the ovary. The 5-year survival rates of dysgerminoma and nondysgerminomatous germ cell tumor of the ovary were 68% (19/28) and 20%(20/101), respectively. The 5-year survival rate of patients with malignant nondysgerminomatous germ cell tumor of the ovary was raised from 3% (1/40) to 42% (15/36) in the recent years. The institution of combination chemotherapy is critical for the improvement with BEP regimen as the best among the three.

CONCLUSIONS

The endodermal sinus tumor of the ovary stands first in the incidence of malignant germ cell tumors of the ovary in China. To improve the prognosis of advanced malignant germ cell tumor of the ovary, BEP regimen is the most effective at present.

The mammalian protein (rbet1) homologous to yeast Bet1p is primarily associated with the pre-Golgi intermediate compartment and is involved in vesicular transport from the endoplasmic reticulum to the Golgi apparatus

Yeast Bet1p participates in vesicular transport from the endoplasmic reticulum to the Golgi apparatus and functions as a soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) associated with ER-derived vesicles. A mammalian protein (rbet1) homologous to Bet1p was recently identified, and it was concluded that rbet1 is associated with the Golgi apparatus based on the subcellular localization of transiently expressed epitope-tagged rbet1. In the present study using rabbit antibodies raised against the cytoplasmic domain of rbet1, we found that the majority of rbet1 is not associated with the Golgi apparatus as marked by the Golgi mannosidase II in normal rat kidney cells. Rather, rbet1 is predominantly associated with vesicular spotty structures that concentrate in the peri-Golgi region but are also present throughout the cytoplasm. These structures colocalize with the KDEL receptor and ERGIC-53, which are known to be enriched in the intermediate compartment. When the Golgi apparatus is fragmented by nocodazole treatment, a significant portion of rbet1 is not colocalized with structures marked by Golgi mannosidase II or the KDEL receptor. Association of rbet1 in cytoplasmic spotty structures is apparently not altered by preincubation of cells at 15 degrees C. However, upon warming up from 15 to 37 degrees C, rbet1 concentrates into the peri-Golgi region. Furthermore, rbet1 colocalizes with vesicular stomatitis virus G-protein en route from the ER to the Golgi. Antibodies against rbet1 inhibit in vitro transport of G-protein from the ER to the Golgi apparatus in a dose-dependent manner. This inhibition can be neutralized by preincubation of antibodies with recombinant rbet1. EGTA is known to inhibit ER-Golgi transport at a stage after vesicle docking but before the actual fusion event. Antibodies against rbet1 inhibit ER-Golgi transport only when they are added before the EGTA-sensitive stage. These results suggest that rbet1 may be involved in the docking process of ER-derived vesicles with the cis-Golgi membrane.

A SNARE involved in protein transport through the Golgi apparatus

In eukaryotic cells, the Golgi apparatus receives newly synthesized proteins from the endoplasmic reticulum (ER) and delivers them after covalent modification to their destination in the cell. These proteins move from the inside (cis) face to the plasma-membrane side (trans) of the Golgi, through a stack of cisternae, towards the trans-Golgi network (TGN), but very little is known about how proteins are moved through the Golgi compartments. In a model known as the maturation model, no special transport process was considered necessary, with protein movement along the Golgi being achieved by maturation of the cisternae. Alternatively, proteins could be transported by vesicles or membrane tubules. Although little is known about membrane-tubule-mediated transport, the molecular mechanism for vesicle-mediated transport is quite well understood, occurring through docking of SNAREs on the vesicle with those on the target membrane. We have now identified a protein of relative molecular mass 27K which is associated with the Golgi apparatus. The cytoplasmic domain of this protein or antibodies raised against it quantitatively inhibit transport in vitro from the ER to the trans-Golgi/TGN, acting at a stage between the cis/medial- and the trans-Golgi/TGN. This protein, which behaves like a SNARE and has been named GS27 (for Golgi SNARE of 27K), is identical to membrin, a protein implicated earlier in ER-to-Golgi transport. Our results suggest that protein movement from medial- to the trans-Golgi/TGN depends on SNARE-mediated vesicular transport.

N-Ethylmaleimide-sensitive factor (NSF) and alpha-soluble NSF attachment proteins (SNAP) mediate dissociation of GS28-syntaxin 5 Golgi SNAP receptors (SNARE) complex

Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) GS28 and syntaxin 5 can be reciprocally coimmunoprecipitated from Golgi extracts, suggesting that they exist in a protein complex. When Golgi extract is preincubated with soluble NSF attachment proteins (alpha-SNAP) and N-ethylmaleimide-sensitive factor (NSF) under conditions that allow ATP hydrolysis by NSF, GS28 and syntaxin 5 become dissociated. GS28 and syntaxin 5 remain in a protein complex when Golgi extract is preincubated with similar amounts of alpha-SNAP and NSF under conditions that prevent ATP hydrolysis by NSF, suggesting that ATP hydrolysis by NSF is necessary for dissociating the GS28-syntaxin 5 complex. Since preincubation of Golgi extract with either alpha-SNAP or NSF alone has no effect on the GS28-syntaxin 5 complex, a concerted action of alpha-SNAP and NSF therefore mediates the dissociation of the GS28-syntaxin 5 complex. Furthermore, GS28 but not syntaxin 5 is capable of binding to immobilized alpha-SNAP when the GS28-syntaxin 5 complex is dissociated.

GS15, a 15-kilodalton Golgi soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) homologous to rbet1

Bet1p plays an essential role in vesicular transport from the endoplasmic reticulum (ER) to the Golgi in yeast, and it functions as a vesicle soluble N-ethylmaleimide-sensitive factor protein receptor (v-SNARE). A mammalian protein related to Bet1p has been reported previously and was referred to as rbet1. We have now identified a new mammalian protein that is homologous to rbet1 (28% amino acid identity). mRNA for this rbet1 homologue is widely expressed in rat tissues. Affinity-purified polyclonal antibodies raised against recombinant protein specifically recognized a 15-kilodalton integral membrane protein highly enriched in Golgi membranes. Indirect immunofluorescence microscopy revealed that this protein is specifically associated with the Golgi apparatus in diverse cell types. Biochemical characterization established that this protein behaves like a SNARE and was named GS15 (Golgi SNARE with a size of 15 kilodaltons). These properties raise the possibility that GS15 is a novel SNARE mediating a yet to be defined transport event associated with the Golgi apparatus.

Specificities of anti-sialyl-Tn and anti-Tn monoclonal antibodies generated using novel clustered synthetic glycopeptide epitopes

The fine specificities of MAbs generated using novel synthetic clustered STn and Tn glycopeptides as immunogens were compared with the anti-TAG-72 antibodies B72.3 and CC49. Hapten inhibition experiments demonstrated the specificity of several of the MAbs for STn and Tn expressed on ovine submaxillary mucin and tumor derived MUC-1 mucin. Amongst the STn specific MAbs only the B195.3 MAb shows absolute dependence on the presence of sialic acid and specificity to the simple disaccharide NANAA alpha2-6-GalNAc. Identification of tumor associated carbohydrate epitopes in cluster and monomer configurations are possible using MAbs detecting the defined structure specificities described herein.

Endoplasmic reticulum retention mediated by the transmembrane domain of type II membrane proteins Sec12p and glucosidase 1

The yeast Sec12p, a type II protein localized to the yeast endoplasmic reticulum (ER), is similarly localized to the ER when expressed in mammalian cells. Replacing the transmembrane domain of the plasma membrane molecule dipeptidyl peptidase IV (D4) with that of Sec12p or the ER-localized enzyme glucosidase 1 resulted in the ER retention of the chimeric molecules, as assessed by immunocytochemical localization and the persistence of pulse-labeled proteins in the endoglycosidase H-sensitive form. Retention is not due to gross misfolding as these chimeras remained enzymatically active. Density gradient analysis revealed that the ER-localized chimeric molecules form high molecular weight oligomers quickly after synthesis. The type II transmembrane domain of ER proteins could therefore mediate retention in the ER.

[China-made paclitaxel in the treatment of advanced ovarian cancer: a clinical analysis of 32 cases]

OBJECTIVE

To study the effect and toxicities of China-made paclitaxel in the treatment of advanced epithelial ovarian carcinoma.

METHODS

Thirty-two patients were divided into two groups. single paclitaxel group (SPG): paclitaxel was only given to twelve untreated patients or those who had been given only one course of chemotherapy at a dose of 175 mg/m2 in 5% glucose 500 ml, i.v. for 3 hours; and combined paclitaxel group (CPG): paclitaxel 135 mg/m2 in 5% glucose 55 ml, i.v. for 3 hours on day 1 plus cisplatin 70-80 mg/m2 or carboplatin 300 mg/m2, i.v. on day 2, was administered to 20 patients with persistent or recurrent tumor after platinum based chemotherapy. Four weeks were defined as one course in both groups. At least two courses were given except those with tumor progression after one course.

RESULTS

The overall response rate was 39%. It was 27% and 45% in the SPG and CPG. The chief side effects were moderate myelosuppression, peripheral neuropathy (myalgia, arthralgia, peripheral neuritis), severe alopecia, etc., but no hypersensitivity. One patient died from intestinal perforation.

CONCLUSIONS

China-made paclitaxel is effective as in treating ovarian carcinoma especially for platinum-resistant patients. The toxic effects are tolerable to the patients.

Association of U2 snRNP with the spliceosomal complex E

In metazoans, the E complex is operationally defined as an ATP-independent spliceosomal complex that elutes as a single peak on a gel filtration column and can be chased into spliced products in the presence of an excess of competitor pre-mRNA. The A complex is the first ATP-dependent functional spliceosomal complex. U1 snRNP first binds tightly to the 5'splice site in the E complex and U2 snRNP first binds tightly to the branch site in the A complex. In this study, we have generated and characterized a monoclonal antibody (mAb 4G8) directed against SAP 62, a component of U2 snRNP and a subunit of the essential mammalian splicing factor SF3a. We show that this antibody is highly specific for SAP 62, detecting only SAP 62 on Western blots and immunoprecipitating only SAP 62 from nuclear extracts. The anti-SAP 62 antibody also immunoprecipitates U2 snRNP and the A complex. Significantly, however, we find that the E complex is also efficiently immunoprecipitated by the anti-SAP 62 antibody. This antibody does not cross-react with any E complex-specific components, indicating that SAP 62 itself is associated with the E complex. To determine whether other U2 snRNP components are associated with the E complex, we used antibodies to the U2 snRNP proteins B"and SAP 155. These antibodies also specifically immunoprecipitate the E complex. These observations indicate that U2 snRNP is associated with the E complex. However, we find that U2 snRNP is not as tightly bound in the E complex as it is in the A complex. The possible significance of the weak association of U2 snRNP with the E complex is discussed.

The mammalian homolog of yeast Sec13p is enriched in the intermediate compartment and is essential for protein transport from the endoplasmic reticulum to the Golgi apparatus

The role of COPII components in endoplasmic reticulum (ER)-Golgi transport, first identified in the yeast Saccharomyces cerevisiae, has yet to be fully characterized in higher eukaryotes. A human cDNA whose predicted amino acid sequence showed 70% similarity to the yeast Sec13p has previously been cloned. Antibodies raised against the human SEC13 protein (mSEC13) recognized a cellular protein of 35 kDa in both the soluble and membrane fractions. Like the yeast Sec13p, mSEC13 exist in the cytosol in both monomeric and higher-molecular-weight forms. Immunofluorescence microscopy localized mSEC13 to the characteristic spotty ER-Golgi intermediate compartment (ERGIC) in cells of all species examined, where it colocalized well with the KDEL receptor, an ERGIC marker, at 15 degrees C. Immunoelectron microscopy also localized mSEC13 to membrane structures close to the Golgi apparatus. mSEC13 is essential for ER-to-Golgi transport, since both the His6-tagged mSEC13 recombinant protein and the affinity-purified mSEC13 antibody inhibited the transport of restrictive temperature-arrested vesicular stomatitis virus G protein from the ER to the Golgi apparatus in a semi-intact cell assay. Moreover, cytosol immunodepleted of mSEC13 could no longer support ER-Golgi transport. Transport could be restored in a dose-dependent manner by a cytosol fraction enriched in the high-molecular-weight mSEC13 complex but not by a fraction enriched in either monomeric mSEC13 or recombinant mSEC13. As a putative component of the mammalian COPII complex, mSEC13 showed partially overlapping but mostly different properties in terms of localization, membrane recruitment, and dynamics compared to that of beta-COP, a component of the COPI complex.

Detection of Epstein-Barr virus DNA in virus-infected cells by electron microscopic in situ hybridization

We describe a procedure for in situ hybridization using a biotinylated Epstein-Barr virus (EBV) sequence with detection at the light and electron microscopic levels. In situ hybridization using an immunogold-silver staining detection system was used to identify biotinylated DNA probes in cell smears and in Lowicryl K4M-embedded EBV-infected and -noninfected cell lines. At the light microscopic level, the reaction product of hybridized EBV DNA sequence seemed to be located mainly in the nuclei. The labelling was dependent on the cell strains. However, at the electron microscopic level, the reaction product was evident as spots or clusters distributed not only in the nuclei of EBV-infected cells but also in the cytoplasm and extracellular particles. These findings suggest that immature particles in the cytoplasm contain EBV DNA. This procedure can be applied to the observation and identification of virus infection.

Biomarkers in airway tumors

Despite advances and improvements in diagnosis and treatment of upper aerodigestive tumors including head and neck and lung cancers, the overall survival rate of these patients remains poor. Prevention, early diagnosis, and novel therapy are under active investigation to improve the outcome of the diseases. In particular, chemopreventive strategy is a novel approach to reduce the invasive tumors by reversing the premalignant lesions with certain differentiating agents (i.e., retinoids). To conduct effective chemopreventive trials, there has been a great surge of interest in defining the biomarkers associated with the specific stages of the carcinogenesis and with intermediate end points during the therapy. Carcinogenesis in the upper aerodigestive tract has been explained by two theories, field cancerization and multistep process. The driving forces behind these processes are noted by accumulated genetic abnormalities in the entire epithelium of the airway. These genetic abnormalities include chromosome abnormalities, specific gene alterations (i.e., ras gene family, tumor suppressor genes, growth factors and their receptors), and proliferation and differentiation markers. These biomarkers are herein described in this review article.

[Primary malignant melanoma of the vagina: a report of 22 cases]

In this paper, 22 patients from 1973 through 1994 with primary malignant melanoma are retrospectively analyzed. Vaginal bleeding, discharge and a tumor mass were the chief complaints. The most common site of the tumor origin was the lower third of the anterior and postrior vaginal wall. The 5-year survival rate of 18 previously untreated patients was 11% (2/18). Of the 18 patients, 9 in stage I treated by surgery and postoperative chemothreoapy and/or radiotherapy survived for an average of 33 months. Two of the 9 patients receiving radical surgery survived for more than 5 years. None of the remaining 9 patients in stage II-IV treated with chemotherapy and/or radiotherapy survived longer than 2 years. The survival time differed significantly in patients with and without pelvic lymph node metastasis (7 versus 41 months) and in those with and without vascular tumor thrombi (13 versus 43 months). Mitotic index of tumor cells and lymphocytic infiltration were of no prognostic value.

GS28, a 28-kilodalton Golgi SNARE that participates in ER-Golgi transport

Little is known about the integral membrane proteins that participate in the early secretory pathway of mammalian cells. The complementary DNA encoding a 28-kilodalton protein (p28) of the cis-Golgi was cloned and sequenced. The protein was predicted to contain a central coiled-coil domain with a carboxyl-terminal membrane anchor. An in vitro assay for endoplasmic reticulum-Golgi transport was used to show that p28 participates in the docking and fusion stage of this transport event. Biochemical studies established that p28 is a core component of the Golgi SNAP receptor (SNARE) complex.

A novel chimera gene between EWS and E1A-F, encoding the adenovirus E1A enhancer-binding protein, in extraosseous Ewing's sarcoma

Ewing's sarcoma/PNET, a tumor of the bone and soft tissue, is one of the most common causes of tumor death among youths. This tumor does not have specific phenotypes, but does have characteristic chromosomal translocations. Furthermore, the expression of EWS/FLI-1 or EWS/ERG chimeric genes was found to be generated through a t(11;22)(q24;q12) or a t(21;22)(q22;q12) translocation. In this study, we identified a new chimera gene between the transactivation domain of EWS and E1A-F, encoding the adenovirus E1A enhancer-binding protein. Since E1A-F is known to activate matrix metalloproteinase genes, the chimera gene may possibly be involved in tumor progression and could be a novel tumor marker for Ewing's sarcoma/PNET.

Cytotoxicity of KDEL-terminated ricin toxins correlates with distribution of the KDEL receptor in the Golgi

DNAs encoding ricin toxin A chain (RTA), with or without a C-terminal endoplasmic reticulum retention signal KDEL, were subcloned into pGEX2T bacterial expression plasmid. After transformation of JM105 E. coli cells and induction with isopropylthio-beta-galactoside (IPTG), fusion proteins were bound to an immobilized glutathione matrix and recombinant ricin A chains released with thrombin. Both recombinant wild-type RTA and RTA with KDEL had immunological reactivity and catalytic activity indistinguishable from plant RTA. The bacterial RTA products reassociated with plant ricin B chain (RTB) similarly to plant RTA. Cell cytotoxicities were measured on seven cell lines for each A-chain and heterodimer. Although KDEL sequences enhanced cytotoxicity in most cases, significant variability was observed. In each case, addition of KDEL enhanced A-chain cytotoxicity more than holotoxin cytotoxicity. Three cell lines showed reduced KDEL enhancement of both RTA and ricin cytotoxicity. The concentration of KDEL receptor was examined on each cell line by immunofluorescence microscopy with an antireceptor monoclonal antibody. Differences in sensitivity to KDEL-containing toxins correlated with altered distribution of KDEL receptor between endoplasmic reticulum (ER) and Golgi compartments.