Isolation and analysis of two cellulase cDNAs from Orpinomyces joyonii

Two cellulase cDNAs, celB29 and celB2, were isolated from a cDNA library derived from mRNA extracted from the anaerobic fungus, Orpinomyces joyonii strain SG4. The nucleotide sequences of celB2 and celB29 and the primary structures of the proteins encoded by these cDNAs were determined. The larger celB29 cDNA was 1966bp long and encoded a 477 amino acid polypeptide with a molecular weight of 54kDa. Analysis of the 1451bp celB2 cDNA revealed an 1164bp open reading frame coding for a 44kDa protein consisting of 388 amino acids. Both deduced proteins had a high sequence similarity in central regions containing putative catalytic domains. Primary structure analysis revealed that CelB29 contained a Thr/Pro-rich sequence that separated the N-terminal catalytic domain from a C-terminal reiterated region of unknown function. Homology analysis showed that both enzymes belong to glycosyl hydrolase family 5 and were most closely related to endoglucanases from the anaerobic fungi Neocallimastic patriciarum, Neocallimastix frontalis and Orpinomyces sp. The classification of CelB29 and CelB2 as endoglucanases was supported by enzyme assays. The cloned enzymes had high activities towards barley beta-glucan, lichenan and carboxymethylcellulose (CMC), but not Avicel, laminarin, pachyman, xylan and pullulan. In addition, CelB29 and CelB2 showed activity against p-nitrophenyl-beta-D-cellobioside (pNP-G(2)) to p-nitrophenyl-beta-D-cellopentaoside (pNP-G(5)) but not p-nitrophenyl-beta-D-glucopyranoside (pNP-G(1)) with preferential activity against p-nitrophenyl-beta-D-cellotrioside (pNP-G(3)). Based on these results, we proposed that CelB29 and CelB2 are endoglucanases with broad substrate specificities for short- and long-chain beta-1,4-glucans.

T-0162, a novel free radical scavenger, reduces myocardial infarct size in rabbits

1. We investigated the effects of 1-(3-tert-butyl-2-hydroxy-5-methoxyphenyl)-3-(3-pyridylmethyl)urea hydrochloride (T-0162), a novel low-molecular weight free radical scavenger, on the generation of superoxide anions and hydroxyl radicals in vitro and in vivo and on myocardial infarct (MI) size in an in vivo model of MI in rabbits. 2. It was found that T-0162 scavenged both superoxide anions and hydroxyl radicals in a concentration-dependent manner in vitro. 3. In an in vivo rabbit model with 30 min coronary occlusion and 30min reperfusion, T-0162 scavenged hydroxyl radicals generated in the myocardium during reperfusion. 4. Anaesthetized open-chest Japanese white male rabbits were subjected to 30 min coronary occlusion and 48 h reperfusion. The control group (n = 10) was infused with 10% lecithin solution for 220 min from 10 min before occlusion to 180 min after reperfusion. The pretreatment group (n = 10) was infused with T-0162 dissolved in 10% lecithin solution for 220 min from 10 min before occlusion to 180 min after reperfusion at a rate of 400 microg/kg per min. The post-treatment group (n = 10) was injected with an i.v. bolus of 10 mg/kg T-0162 and was then infused with 400 microg/kg per min T-0162 for 190 min from 10 min before reperfusion to 180 min after reperfusion. After 48 h reperfusion, infarct size was measured histologically and expressed as a percentage of area at risk (AAR). 5. There was no significant difference in haemodynamic parameters among the three groups throughout the experimental period. The per cent infarct size of the AAR in the T-0162 groups (24.8+/-4.3 and 30.5+/-3.9% for pre- and posttreatment groups, respectively) was significantly reduced compared with control (44.7+/-4.1%; P<0.05). There was no significant difference in the AAR among the three groups. 6. In conclusion, T-0162 reduces MI size through the inhibition of reperfusion injury.

WIM/WISE NMR studies of chain dynamics in solid polymers and blends

Wideline separation (WISE) NMR with window-less isotropic mixing (WIM) is developed as a method to study the dynamics of polymers and blends. This experiment is designed to measure the dynamics of polymers through the proton lineshapes that are correlated with the carbon chemical shifts in two-dimensional NMR experiments. If the atoms experience large amplitude fluctuations that are fast compared to the dipolar broadening, then the proton lines will be narrowed relative to rigid solids. We have modified the WISE experiment by replacing the cross polarization step with WIM to quench spin diffusion during the cross polarization so that the proton linewidths can be directly related to the chain dynamics. Two-dimensional WIM/WISE has been used to measure the main-chain and side-chain dynamics in poly(n-butyl methacrylate) and blends of polystyrene and poly(vinyl methyl ether).

Crystal structure of beta-ketoacyl-acyl carrier protein synthase III. A key condensing enzyme in bacterial fatty acid biosynthesis

Beta-ketoacyl-acyl carrier protein synthase III (FabH), the most divergent member of the family of condensing enzymes, is a key catalyst in bacterial fatty acid biosynthesis and a promising target for novel antibiotics. We report here the crystal structures of FabH determined in the presence and absence of acetyl-CoA. These structures display a fold that is common for condensing enzymes. The observed acetylation of Cys(112) proves its catalytic role and clearly defines the primer binding pocket. Modeling based on a bound CoA molecule suggests catalytic roles for His(244) and Asn(274). The structures provide the molecular basis for FabH substrate specificity and reaction mechanism and are important for structure-based design of novel antibiotics.

Study of thrombopoietin for gene therapy of thrombocytopenia

Thrombopoietin (TPO) is likely to he a potent, specific and reliable medication in the treatment of thrombocytopenia. A TPO-highly-expressed plasmid pcDNA3-TPO was constructed and a primary study was made on the expression of TPO cDNA in vitro and gene transfer study for thrombocytopenia in vivo. rhTPO showed complete and stable bioactivity by a series of indicators. High expression of TPO was detected in plasma from healthy mice or thrombocytopenia mice model receiving direct intramuscular injection of pcDNA3-TPO. And the platelet level of healthy mice peaked to 1.9-fold of baseline. Mice with CTX-induced thrombocytopenia achieved profound nadirs, acceleration of recovery, even 1.8-2.0-fold supranormal levels of peripheral platelet counts. The results offered experimental support for clinical application of gene therapy for thrombocytopenia via direct intramuscular injection of TPO cDNA.

Molecular basis for triclosan activity involves a flipping loop in the active site

The crystal structure of the Escherichia coli enoyl reductase-NAD+-triclosan complex has been determined at 2.5 A resolution. The Ile192-Ser198 loop is either disordered or in an open conformation in the previously reported structures of the enzyme. This loop adopts a closed conformation in our structure, forming van der Waals interactions with the inhibitor and hydrogen bonds with the bound NAD+ cofactor. The opening and closing of this flipping loop is likely an important factor in substrate or ligand recognition. The closed conformation of the loop appears to be a critical feature for the enhanced binding potency of triclosan, and a key component in future structure-based inhibitor design.

Interaction of tyrosyl aryl dipeptides with S. aureus tyrosyl tRNA synthetase: inhibition and crystal structure of a complex

Tyrosyl aryl dipeptide inhibitors of S. aureus tyrosyl tRNA synthetase have been identified with IC50 values down to 0.5 microM. A crystal structure of the enzyme complexed to one of the inhibitors shows occupancy of the tyrosyl binding pocket coupled with inhibitor interactions to key catalytic residues.

Cooperative structural dynamics and a novel fidelity mechanism in histidyl-tRNA synthetases

The crystal structure of the Staphylococcus aureus histidyl-tRNA synthetase apoprotein has been determined at 2.7 A resolution. Several important loops in the active site either become disordered or adopt very different conformations compared to their ligand-bound states. These include the histidine A motif (Arg257-Tyr262) that is essential for substrate recognition, a loop (Gly52-Lys62) that seems to control the communication between the histidine and ATP binding sites, the motif 2 loop (Glu114-Arg120) that binds ATP, and the insertion domain that is likely to bind tRNA. These ligand-induced structural changes are supported by fluorescence experiments, which also suggest highly cooperative dynamics. A dynamic and cooperative active site is most likely necessary for the proper functioning of the histidyl-tRNA synthetase, and suggests a novel mechanism for improving charging fidelity.

The sleep disorder canine narcolepsy is caused by a mutation in the hypocretin (orexin) receptor 2 gene

Narcolepsy is a disabling sleep disorder affecting humans and animals. It is characterized by daytime sleepiness, cataplexy, and striking transitions from wakefulness into rapid eye movement (REM) sleep. In this study, we used positional cloning to identify an autosomal recessive mutation responsible for this sleep disorder in a well-established canine model. We have determined that canine narcolepsy is caused by disruption of the hypocretin (orexin) receptor 2 gene (Hcrtr2). This result identifies hypocretins as major sleep-modulating neurotransmitters and opens novel potential therapeutic approaches for narcoleptic patients.

[Experience of endoscopic sinus operation on 74 cases]

OBJECTIVE

To improve the curative effect of endoscopic sinus operation.

METHOD

The clinical data of nasal cavity and nasal sinus via endoscopic sinus operation on 74 cases (115 sides) were in summary. Of those 74 cases, 65 were followed-up over six mothes.

RESULT

It showed that 44 cases were cured, 18 were improved, 3 were ineffective. The effective rate was 95.4%. The disappearance rate of four symptons-nasal obstruction, headache, purulent nasal discharge and loss of smelling was 95.2%, 92%, 66.7% and 42.5%, respectively. The serious operative complication was absent.

CONCLUSION

It helped to raise thd effect of anesthetization to apply nasal cavity surface anesthesia, nerve block anesthesia. Paying attention to the distinguish of dissection label can help to decrease the occurance of the serious complication of the sinus ethmoidal operation. The operation which was alternatively conducted between endoscope and cavascope, according to the operation requirement, can be carried out more thoroughly and more safely. Cleaning the operation cavity after operation can promote healing.

[Study of histopathology of endometrium following termination of early pregnancy using mifepristone]

OBJECTIVE

To explore the causes of abnormal uterine bleeding following termination of early pregnancy using mifepristone.

METHODS

19 specimens were obtained by curettage on the day immediately after expulsion of gestational sac, 40 specimens on the 7th postabortal day and 20 specimens during 2-12 weeks after induced abortion using mifepristone respectively. The histopathologic changes of the specimens were observed by HE staining, and the expression of human choronic gonadotropin (hCG) and human placental lactogen (hPL) by immunohistochemical studies as well as phloxine-tartrazine staining and Gordon Sweets staining.

RESULTS

It showed that decidua shedding retarded, especially basal decidua. Immunohistochemical studies demonstrated the trophoblasts were still active and might affect pathological changes of local endometrium. The specific granules of endometrial granulocytes disappeared, together with disintegration of the reticular fibers. But in the group which curettage was indicated for abnormal bleeding 2 weeks after abortion, the main cause was incomplete abortion.

CONCLUSIONS

In addition to incomplete abortion, the retardation of decidua shedding and the impairment of endometrium regeneration were responsible for the abnormal uterine bleeding following termination of early pregnancy using mifepristone. The incomplete dissolution of the reticular fibers in basal decidua may induce decidua shedding retardation and incomplete abortion.

Purification and characterization from rat kidney membranes of a novel platelet-activating factor (PAF)-dependent transacetylase that catalyzes the hydrolysis of PAF, formation of PAF analogs, and C2-ceramide

We have previously identified two enzyme activities that transfer the acetyl group from platelet-activating factor (PAF) in a CoA-independent manner to lysoplasmalogen or sphingosine in HL-60 cells, endothelial cells, and a variety of rat tissues. These were termed as PAF:lysoplasmalogen (lysophospholipid) transacetylase and PAF:sphingosine transacetylase, respectively. In the present study, we have solubilized and purified this PAF-dependent transacetylase 13,700-fold from rat kidney membranes (mitochondrial plus microsomal membranes) based on the PAF:lysoplasmalogen transacetylase activity. The mitochondria and microsomes were prepared and washed three times, then solubilized with 0.04% Tween 20 at a detergent/protein (w/w) ratio of 0.1. The solubilized fractions from mitochondria and microsomes were combined and subjected to sequential column chromatographies on DEAE-Sepharose, hydroxyapatite, phenyl-Sepharose, and chromatofocusing. The enzyme was further purified by native-polyacrylamide gel electrophoresis (PAGE) and affinity gel matrix in which the competitive inhibitor of the enzyme, 1-O-hexadecyl-2-N-methylcarbamyl-sn-glycero-3-phosphoethanolamine was covalently attached to the CH-Sepharose. On SDS-PAGE, the purified enzyme showed a single homogeneous band with an apparent molecular mass of 40 kDa. The purified enzyme catalyzed transacetylation of the acetyl group not only from PAF to lysoplasmalogen forming plasmalogen analogs of PAF, but also to sphingosine producing N-acetylsphingosine (C2-ceramide). In addition, this enzyme acted as a PAF-acetylhydrolase in the absence of lipid acceptor molecules. These results suggest that PAF-dependent transacetylase is an enzyme that modifies the cellular functions of PAF through generation of other diverse lipid mediators.

[An experimental investigation of inhibition of interferon on lens epithelial cell growth in vitro]

OBJECTIVE

To investigate the inhibition of alpha-interferon (alpha-IFN) and gamma-interferon (gamma-IFN) on rabbit lens epithelial cell (RLEC) proliferation in vitro and their effective concentrations.

METHODS

The second and third passage of RLEC were used for assay. Various concentrations of alpha-IFN or gamma-IFN were added into the culture medium and RLECs were exposed to these drugs. After 24 and 72 hours, the inhibition of RLECs was determined by counting the RLEC numbers on a counting plate and MTT colorimetric assay.

RESULTS

Alpha-IFN and gamma-IFN may reduce the proliferation of RLECs at the concentration of 10(3) - 10(4) IU/ml. The inhibition of gamma-IFN was a little stronger than that of alpha-IFN.

CONCLUSION

The experiment provides a scientific basis for selection of drugs to prevent after cataract.

[Simultaneous determination of europium and copper in rare earth oxide by use AAS-PLS method]

Partial least squares regression was used to compensate for spectral "overlap" interference of Eu 324. 753 nm with Cu 324.754 nm in atomic absorption spectrometry. We could only use the copper element hollow-cathode lamp to simultaneous determine Eu and Cu in synthetic samples and rare earth oxide, and obtained satisfactory results.

[Effects of apoptosis of synovial lining cells on pathogenesis of osteoarthropathy]

The author counted synovial lining cells(SLCs) of apoptosis in the joints of osteoarthropathy(OA, 12 cases) and control(10 cases) patients. The counts of apoptotic SLC were investigated by gel electrophoretic analysis of DNA extracted from synovium. The apoptotic index(AI) of SLCs in OA(2.04%) was obviously higher than that in controls(0.60%); electrophorectogram of DNA revealed a characteristic ladder pattern of DNA fragments at 200 bp in the OA group. We conclude that apoptosis can be found in synovial lining layer, and the AI of SLCs in the OA group is much higher than that in the control group, implying the high turn-over rate of SLCs in OA; the increasing apoptosis of SLCs may increase lesion factors retained in joints and cause the injury of articular cartilage.

[Effect of acetylcholine receptor antibody derived from myasthenia gravis on the rat central neuronal nicotinic acetylcholine receptor]

Immunoreaction between acetylcholine receptor antibody (AChRab) derived from myasthenia gravis (MG) and neuronal nicotinic acetylcholine receptor (AChR) and the action of AChRab on rat brain stem auditory transmission were investigated by immunocytochemistry and brain stem auditory evoked potential (BAEP) in a search for abnormalities indicating central nervous system (CNS) involvement in this disorder. 25 microliters of AChRab were injected into the ventricular system of rats once every 48 hours for periods of up to a week BAEP examination was taken before and after injection of AChRab. Immunocytochemical investigation of the rat brain sections provided evidence that the neuronal nicotinic AChR like immunoreactivity is widely distributed throughout the rat CNS such as cerebral cortex, hippocampus, motor neurons in brain stem, auditory nucleus cerebellar cortex, etc. Analysis of the immunocytochemical results showed that the distribution property of AChRab in rat CNS correlated well with known neuronal nicotinic AChR subtypes e.g., alpha 7 and alpha 4. BAEP inter peak latency was significantly prolonged in rats after injection of AChRab as compared with the control rats and the rats prior to injection of AChRab. The results indicated that cerebroventricular administration of AChRab not only cause dysfunction of brain stem auditory transmission but also leads to development of experimental autoimmune MG symptoms. It is concluded that AChRab influences the rat brain stem auditory transmission and it is suggested that the pathogenic effect of AChRab is not only limited at neuromuscular junction, but also involves the central neuronal nicotinic AChR.

Antienvelope antibodies are protective against GBV-C reinfection: evidence from the liver transplant model

An assay for the detection of antibody against the second envelope (E2) protein of GB virus type C (GBV-C) has been developed. Early reports suggested that this antibody was a marker of viral clearance, yet it is unknown whether anti-E2 is protective against further GBV-C infection. The primary aims were to determine (1) if posttransplantation immunosuppression alters the prevalence of anti-E2; and (2) if anti-E2 positivity pretransplantation protects against acquisition of GBV-C infection posttransplantation. Fifty-four recipients who underwent orthotopic liver transplantation for end-stage liver disease of nonviral etiologies were tested for GBV-C RNA using a PCR-based assay and anti-E2 antibodies by an enzyme-linked immunoassay. Anti-E2 was present in 35% and in 46% of patients pre- and posttransplantation, respectively. Anti-E2 positivity pretransplantation was strongly associated with anti-E2 positivity after transplantation (P < 0.001); 83% of patients with anti-E2 prior to transplantation remained anti-E2-positive after transplantation. A negative association between presence of GBV-C viremia and presence of anti-E2 was found in all patients tested either prior to or following transplantation (P=0.03). Acquisition of GBV-C infection was significantly lower in patients who were anti-E2-positive prior to transplantation (2/13) compared to those who were anti-E2-negative (12/26) (P=0.05). It is concluded that immunosuppression does not reduce the prevalence of anti-E2 after transplantation in those who are seroreactive prior to transplantation. Anti-E2 appears to be a neutralizing antibody whose presence at the time of liver transplantation protects against acquisition of GBV-C infection in the peritransplantation period.

[Vitrectomy for treatment of retinal detachment caused by macular hole]

OBJECTIVE

To evaluate the effect of vitrectomy and autoserum for treatment of retinal detachment caused by macular hole.

METHODS

19 eyes with retinal detachment caused by macular hole were treated with gas tamponade (C(3)F(8)). The follow-up periods ranged from 6 to 24 months. In the case whose macular hole failed to heal, removal of the remains of prefoveal membrane and/or scratching at the retinal pigment epithelium (RPE) and placing autoserum for 7 minutes in the macular hole were performed.

RESULTS

Closure of macular hole was obtained in 15 eyes (80%). The postoperative visual acuity was 0.05 - 0.4. Macular hole failed to heal in 4 eyes. In one eye the remains of prefoveal membrane were removed; in another 3 eyes, in the macular hole scratching at the retinal pigment epithelium (RPE) and placing autoserum were performed and C(3)F(8) tamponade was used. Anatomical cure was obtained in all the 4 eyes. The final visual acuity was 0.1 or better.

CONCLUSION

The findings show that removal of prefoveal membrane is imperative. Scratch at RPE with placement of autoserum in the macular hole is effective for the macular hole which has failed to respond to conventional vitrectomy with air tamponade.

[Effect of melatonin on mean blood pressure and heart rate in morphine withdrawal rats]

The model of morphine dependent rats was established by gradually increasing the doses of morphine by subcutaneous injection(from 5 mg.kg-1 to 50 mg.kg-1, 5 days). The effects of melatonin(MT) on the mean arterial blood pressure(mABP) and heart rate(HR) were studied in naloxone-precipitated rats. MT was found to inhibit the hypertention and tachycardiac syndromes in morphine withdrawal rats in dose-dependent manner. The concentration of serum norepinephrine(NE) was shown to be decreased by MT. Moreover, regitine was shown to inhibit the increase of mABP in morphine withdrawal rats, but can not inhibit the increase of HR. These results suggest that the inhibitory effect of MT on hypertension and tachycardiac syndromes in morphine withdrawal rats may be mediated by the inhibitory effect of the drug on the sympathetic system.

[Bone scintigraphy in evaluating revascularization of the heat-devitalised autografts in adult dogs]

OBJECTIVE

To establish an animal model of microwave hyperthermic devitalization of long bones and compare bone scintigraphy of the devitalised bone with pathologic examination.

METHOD

16 Mongrel adult dogs were used. Enght 8 cm of one femur of each dog was exposed and isolated by heat-proof material. Two microwave antennas were inserted into the medullary cavity at a distance of 2.5 cm, and the bone was heated intermittently to maintain a surface temperature of 50 degrees C to 60 degrees C for 30 minutes. Bone scintigraphy was carried out at different postoperative time, combined with tetracycline labeling, microangiography with Indian ink and HE staining.

RESULT

About 5 cm - 6 cm of segmental femur was deprived of blood supply after devitalization which was confirmed by microangiography and negative labeling of tetracyclines. At two weeks, the devitalised bone demonstrated a cold region on the scintiscan and no revascularization in microangiography. 12 - 16 weeks after the operation, partial devitalised bone was revascularized and HE staining showed widel bone resorption and minimum formation of new bone. However, the radionuclide uptakes of the devitalised segments were greater than those of the normal femurs. At one year, the devitalised segment was well (not completely) revascularised and showed evident appositional new bone formation. The scintigraphic bone-imaging was slightly lower than that of the normal femur.

CONCLUSION

A strong positive scintiscan in early stage might demonstrate a good potential of revascularization of the heat-devitalised cortical bone rather than its viability. And the scintiscans of long-term follow-up more than one year should be more informative.

[The inhibitory effect of melatonin on morphine withdrawal syndromes and serum monoamines in morphine dependent mice]

OBJECTIVE

To observe the inhibitory effect of melatonin on morphine withdrawal syndromes and serum monoamines in morphine dependent mice.

METHODS

A physical dependent model in mice was established by subcutaneous injection of morphine. The intensity of withdrawal syndromes was evaluated according to the jumping latency and jumping times. The concentration of serum monoamines was detected with HPLC-ECD.

RESULTS

The physical withdrawal syndromes in morphine dependent mice were inhibited partly by four different doses (25, 50, 100, 200 mg/kg) of melatonin and showed a significant dose-dependent manner. The increased concentration of serum norepinephrine and dopamine in morphine-dependent mice could be reduced by large dose (100 mg/kg) of melatonin.

CONCLUSION

The jumping withdrawal syndromes and serum monoamiues in morphine-dependent mice could be inhibited partly by melatonin.

Antibodies against the GB virus C envelope 2 protein before liver transplantation protect against GB virus C de novo infection

GB virus C (GBV-C) is a newly discovered RNA virus related to the Flaviviridae family. Although GBV-C is not yet associated with any cause of liver disease, a humoral immune response against the GBV-C envelope 2 (E2) protein has been observed. Therefore, we studied the prevalence and clinical relevance of GBV-C RNA and anti-E2 antibodies in patients undergoing orthotopic liver transplantation (OLT). In addition, we tested whether the prevalence of anti-E2 antibodies may protect against GBV-C infection. Of the 182 liver recipients included in this study, 117 of these were evaluated for GBV-C recurrence or de novo infection. GBV-C RNA was detected in sera or plasma using single-tube, reverse-transcriptase polymerase chain reaction, and anti-E2 antibody was detected by enzyme immunoassay (EIA). Cumulative patient and graft survival was tested by using Kaplan-Meier analysis. The independence of prognostic values was assessed by using Cox regression analysis. Before OLT, GBV-C RNA and anti-E2 were detected in 4.0% to 28.6% and 10.0% to 68.8%, respectively, of patients suffering from different forms of chronic liver diseases. GBV-C reinfection after OLT was determined in 85.7%. Of the patients without evidence of exposure to GBV-C before OLT, 30 of 65 (46.2%) became GBV-C RNA positive after OLT. None of the 38 patients who were anti-E2 antibody positive before OLT became GBV-C RNA positive after OLT. Neither patient nor graft survival was significantly affected by the presence of either GBV-C RNA or anti-E2 antibody before OLT. Our data indicate that 1) GBV-C RNA positive patients have a high risk of reinfection after OLT, and 2) the presence of anti-E2 antibodies before OLT is associated with an absence of GBV-C infection after OLT, which may indicate a protective role of anti-E2 antibodies.

Expression and regulation of hFIX minigene and cDNA driven by beta-casein gene in mouse mammary gland

Mammary gland specific expression vectors for human clotting factor IX (hFIX) and LacZ reporter gene driven by bovine beta-casein gene were constructed. Vectors were packaged by stearylamine (SA) liposome and were transferred to lactating mice via tail vein. Both hFIX and Lac2 gene could be expressed in the mammary gland of the treated mice. The highest production of hFIX protein was 80.28 ng per mL milk, and more than 85% of hFIX protein appeared to be gamma-carboxylation and biologically active. The results suggested that the 2.0 kb sequence of beta-casein gene including promoter, exon 1 was effective to drive hFIX gene expression in mammary gland and intron 1 of beta-casein gene had an effect on the tissue specific expression. The expression level in mouse milk injected with hFIX minigene vector containing hFIX endogenous intron 1 was increased by above 3 times of that injected with hFIX cDNA vector.

Role of p53 in aziridinylbenzoquinone-induced p21waf1 expression

Quinones are the second largest family of anticancer drugs clinically used in the United States. However, their exact mode of action at the cellular and molecular level is not completely understood. We have shown earlier that the quinone 3,6-diaziridinyl-1,4-benzoquinone (DZQ) leads to the increased expression of p21waf1/cip1/sdi1 protein, an inhibitor of cyclin-dependent kinases. Because p21 has been established as an important negative regulator of the cell cycle, we further investigated the molecular basis of p21 induction by DZQ. Here we report that the induction of p21 by DZQ is regulated at the transcriptional level, and requires the activation of p53, a tumor suppressor protein. In cells that lack functional p53 protein, DZQ-mediated p21 induction is greatly diminished. However, the introduction of a wild type p53 gene into p53-negative cells restores the strong DZQ-inducibility of p21. Restoration of wild type p53 status in HL60 myeloid leukemia cells significantly increases the cells' sensitivity to the cytotoxic effects of DZQ. Thus, our results indicate that the p53-p21 pathway may play a central role in mediating the gene-regulatory and cytotoxic effects of aziridinylbenzoquinones.