Assembly, annotation, and integration of UNIGENE clusters into the human genome draft

The recent release of the first draft of the human genome provides an unprecedented opportunity to integrate human genes and their functions in a complete positional context. However, at least three significant technical hurdles remain: first, to assemble a complete and nonredundant human transcript index; second, to accurately place the individual transcript indices on the human genome; and third, to functionally annotate all human genes. Here, we report the extension of the UNIGENE database through the assembly of its sequence clusters into nonredundant sequence contigs. Each resulting consensus was aligned to the human genome draft. A unique location for each transcript within the human genome was determined by the integration of the restriction fingerprint, assembled genomic contig, and radiation hybrid (RH) maps. A total of 59,500 UNIGENE clusters were mapped on the basis of at least three independent criteria as compared with the 30,000 human genes/ESTs currently mapped in Genemap'99. Finally, the extension of the human transcript consensus in this study enabled a greater number of putative functional assignments than the 11,000 annotated entries in UNIGENE. This study reports a draft physical map with annotations for a majority of the human transcripts, called the Human Index of Nonredundant Transcripts (HINT). Such information can be immediately applied to the discovery of new genes and the identification of candidate genes for positional cloning.

Prevention of hypertension by irbesartan in Dahl S rats relates to central angiotensin II type 1 receptor blockade

Hypertension in Dahl S rats on high-salt intake is in general considered a model of "low-renin hypertension," unresponsive to treatment with blockers of the renin-angiotensin system. However, direct central administration of an angiotensin II type 1 (AT(1)) receptor blocker prevents both the sympathoexcitation and hypertension caused by high-salt intake in Dahl S rats. In the present study, we tested the hypothesis that chronic peripheral administration of an AT(1) receptor blocker inhibits the salt-induced hypertension relative to the extent of central AT(1) receptor blockade that is induced. Dahl S rats received a high-salt (1370 micromol Na(+)/g) or regular (101 micromol Na(+)/g) diet from 4 to 8 weeks of age. In 3 different sets of experiments, Dahl S on high salt were randomized to intracerebroventricular (ICV) treatment with control infusion versus irbesartan at 50 or 250 microg. kg(-1). d(-1), oral treatment with control versus irbesartan at 125 or 500 mg. kg(-1). d(-1) once daily by gavage, or subcutaneous treatment with control versus irbesartan at 50 or 150 mg. kg(-1). d(-1) by once daily injection. At 8 weeks of age, MAP was measured in conscious rats at rest and in response to angiotensin II ICV or IV. On high-salt intake, Dahl S developed the anticipated marked increase in MAP to approximately 160 mm Hg. Irbesartan ICV did not affect pressor responses to angiotensin II IV, but irbesartan administered subcutaneously or by gavage markedly inhibited these responses. Irbesartan ICV or by gavage partially inhibited pressor responses to angiotensin II ICV and the development of hypertension. Irbesartan subcutaneously at the higher dose more completely inhibited pressor responses to angiotensin II ICV and fully prevented the salt-induced hypertension. The degree of central but not peripheral AT(1) receptor blockade parallels the antihypertensive effect of irbesartan, indicating that inhibition of the brain renin-angiotensin system can contribute to a significant extent to the therapeutic effectiveness of AT(1) receptor blockers such as irbesartan when administered in sufficiently high doses to cause central AT(1) receptor blockade.

[The efficiency of algae removal from drinking water by ferrate]

This paper studied the efficiency of algae removal by ferrate from two kinds of raw water which were collected from Donghu and Tiegang reservoir respectively. The experimental results showed that the removal efficiency of algae reached about 95% only through PAC coagulation when the raw water was extracted from Donghu reservoir in which most of algae was Chlorella. But dealing with Tiegang raw water in which the majority of algae were Oscillatoria, terrate was used as pre-oxidant coupling with PAC coagulation not only using PAC to flocculate and the efficiency of algae removal could be up to 97.85%. However this treatment method using ferrate as pre-oxidant overmatched the traditional method prechlorination for algae removal.

Morphine applied to the ventrolateral orbital cortex produces a naloxone-reversible antinociception in the rat

Our previous findings have indicated that the ventrolateral orbital cortex (VLO) may be involved in modulation of nociception and plays an important role as a higher center of an endogenous analgesic system (a feedback loop) consisting of spinal cord-nucleus submedius (Sm)-VLO-periaqueductal gray (PAG)-spinal cord. To further investigate the neurotransmitter mechanism involved in this nociceptive modulatory pathway, we tested the effects of microinjection of morphine (5 microg, 0.5 microl) into VLO on the tail flick (TF) reflex. The results show that a unilateral microinjection of morphine into VLO dose-dependently suppresses the TF reflex. Furthermore, 6 min after termination of morphine injection, microinjection of opioid receptor antagonist naloxone (1.5 microg, 0.5 microl) into the same VLO site reverses this morphine-evoked inhibition of TF reflex. These results suggest that morphine application to the VLO may directly or indirectly activate VLO neurons projecting to the PAG through the opioid receptor mediation leading to activation of the brainstem descending inhibitory system and depression of the nociceptive inputs at the spinal cord level.

Evidence that reduced renal medullary nitric oxide synthase activity of dahl s rats enables small elevations of arginine vasopressin to produce sustained hypertension

On the basis of observations supporting the functional importance of nitric oxide (NO) in the regulation of renal medullary function, and a reduced nitric oxide synthase (NOS) enzyme activity in the outer medulla of the Dahl salt-sensitive (SS/Mcw) rats, we hypothesized that these inbred rats would have reduced capacity to synthesize renal medullary NO. This reduced capacity would sensitize them to the hypertensive effects of small elevations of circulating arginine vasopressin (AVP). SS/Mcw and Brown Norway (BN/Mcw) rats with implanted arterial and venous catheters were fed a 0.4% salt diet and infused intravenously for 14 days with a subpressor dose of AVP (2 ng/kg per min). Mean arterial pressure (MAP) was measured 2 hours daily in unanesthetized rats maintained in their home cages. MAP in SS/Mcw rats increased during day 1 of AVP infusion from a control level of 127+/-0.9 mm Hg to an average of 147+/-1.6 mm Hg after 14 days. MAP did not return to control values during the 3 days after the end of AVP infusion. BN/Mcw rats showed no changes of MAP during 14 days of AVP infusion (90.4+/-0.6 mm Hg and 92.3+/-0.4 mm Hg). Northern blot analysis of renal tissue from vehicle (saline) -infused rats demonstrated that NOS I and NOS III mRNA expression was significantly less in SS/Mcw rats in the renal outer medulla compared with BN/Mcw rats. We conclude that small, normally subpressor elevations of plasma AVP can produce chronic hypertension in SS/Mcw rats and that this phenomenon is related to the reduced medullary NOS enzyme activity, which in turn reduces the AVP-stimulated NO synthesis.

Mortality after coronary artery occlusion in different models of cardiac hypertrophy in rats

Chronic treatment with minoxidil induces cardiac trophic and sympathetic responses, which may increase the propensity for lethal arrhythmias. To test this hypothesis, acute coronary artery occlusion was performed in conscious normotensive rats treated for 2 or 5 weeks with minoxidil with the use of a 2-stage approach to cause a myocardial infarction. For comparison, rats with aortocaval (A-V) shunts and spontaneously hypertensive rats (SHR) were studied. Minoxidil increased left ventricular and right ventricular weights by 15% to 20%, and the A-V shunt increased these weights by 30% to 40%. In SHR, left ventricular weight was increased by 50%, and right ventricular weight was increased by 25%. In rats treated with minoxidil for 5 weeks, coronary artery occlusion caused a rapid and marked mortality, and 4 hours after myocardial infarction, only 18% of these rats were alive versus 61% of the control rats. In rats with the A-V shunt, coronary artery occlusion was also associated with increased mortality, and after 6 hours, 33% were still alive compared with 59% of the control rats. In contrast, SHR with marked hypertension and cardiac hypertrophy showed only a minor increase in mortality (survival rates were 53% versus 60% in SHR versus Wistar-Kyoto rats, respectively). Mortality was preceded by high arrhythmia scores, and ventricular fibrillation was the cause of death. Discontinuation of minoxidil for 1 week, sympathetic blockade with nadolol or clonidine, or blockade of the renin-angiotensin system with enalapril or losartan did not improve minoxidil-induced excess mortality. We conclude that ventricular stretch and other mechanisms (eg, cardiac vagal activity) in rats appear to be more potent than hypertension-induced left ventricular hypertrophy in predisposing for lethal arrhythmias in the setting of acute ischemia.

Expression profiling reveals fundamental biological differences in acute myeloid leukemia with isolated trisomy 8 and normal cytogenetics

Acute myeloid leukemia (AML) is a heterogeneous group of diseases. Normal cytogenetics (CN) constitutes the single largest group, while trisomy 8 (+8) as a sole abnormality is the most frequent trisomy. How trisomy contributes to tumorigenesis is unknown. We used oligonucleotide-based DNA microarrays to study global gene expression in AML+8 patients with +8 as the sole chromosomal abnormality and AML-CN patients. CD34(+) cells purified from normal bone marrow (BM) were also analyzed as a representative heterogeneous population of stem and progenitor cells. Expression patterns of AML patients were clearly distinct from those of CD34(+) cells of normal individuals. We show that AML+8 blasts overexpress genes on chromosome 8, estimated at 32% on average, suggesting gene-dosage effects underlying AML+8. Systematic analysis by cellular function indicated up-regulation of genes involved in cell adhesion in both groups of AML compared with CD34(+) blasts from normal individuals. Perhaps most interestingly, apoptosis-regulating genes were significantly down-regulated in AML+8 compared with AML-CN. We conclude that the clinical and cytogenetic heterogeneity of AML is due to fundamental biological differences.

Mutations in the RNA component of RNase MRP cause a pleiotropic human disease, cartilage-hair hypoplasia

The recessively inherited developmental disorder, cartilage-hair hypoplasia (CHH) is highly pleiotropic with manifestations including short stature, defective cellular immunity, and predisposition to several cancers. The endoribonuclease RNase MRP consists of an RNA molecule bound to several proteins. It has at least two functions, namely, cleavage of RNA in mitochondrial DNA synthesis and nucleolar cleaving of pre-rRNA. We describe numerous mutations in the untranslated RMRP gene that cosegregate with the CHH phenotype. Insertion mutations immediately upstream of the coding sequence silence transcription while mutations in the transcribed region do not. The association of protein subunits with RNA appears unaltered. We conclude that mutations in RMRP cause CHH by disrupting a function of RNase MRP RNA that affects multiple organ systems.

A battery-powered notebook thermal cycler for rapid multiplex real-time PCR analysis

A compact, real-time PCR instrument was developed for rapid, multiplex analysis of nucleic acids in an inexpensive, portable format. The instrument consists of a notebook computer, two reaction modules with integrated optics for four-color fluorescence detection, batteries, and a battery-charging system. The instrument weighs 3.3 kg, measures 26 x 22 x 7.5 cm, and can run continuously on the internal batteries for 4 h. Independent control of the modules allows differing temperature profiles and detection schemes to be run simultaneously. Results are presented that demonstrate rapid (1) detection and identification of Bacillus subtilis and Bacillus thuringensis spores and (2) characterization of a single nucleotide polymorphism for the hereditary hemochromatosis gene.

[Comparison the medical prescriptions between of Zhongjing and Xiao pin fang (Jotting Prescriptions)]

Based on the comparison between the prescriptions of Zhongjing's Prescriptions and Jotting Prescriptions, it can be seen that Xiao pin fang (Jotting Prescriptions) in many aspects, reflecting partly the tendency of changes in prescriptions from the Eastern Han dynasty to Liu Song period of the Northern and Southern dynasties.

[Relationship between memory enhancement induced by nitric oxide donor and brain ADP-ribosyltransferase in rats]

In order to explore the signal transduction pathway of nitric oxide (NO) related to learning and memory, the effects of intracerebral ventricular injection (icv) of NO donor sodium nitroprusside (SNP) alone or along with ADP-ribosyltransferase (ADPRT) inhibitor nicotinamide (NIC) on learning and memory behavior were investigated in rats. Brain ADPRT activity was analyzed using high performance liquid chromatography. The results showed that SNP (0.36 microgram, icv) facilitated short-term and long-term memory in passive avoidance response and elevated learning and memory ability in active avoidance response. NIC (1.5 mg, icv) blocked the effect of SNP. Training in active avoidance task raised ADPRT activity in hippocampus. Treatment with SNP (icv) before training caused significant elevation of ADPRT activity in hippocampus and cerebral cortex. The results above support the view that ADPRT may be one of the target molecules of NO action.

Convergent projections of Drosophila olfactory neurons to specific glomeruli in the antennal lobe

Candidate Drosophila olfactory receptors (ORs) provide molecular tools to investigate how the organization of the Drosophila olfactory system determines the coding of olfactory stimuli. Neurons in the third antennal segment and maxillary palp appear to express different ORs. Individual olfactory neurons send axonal projections to glomeruli in the antennal lobe. Using transgenic flies, we provide evidence that the neurons expressing a given OR gene, which have cell bodies distributed among neurons expressing other ORs, converge in their projections to topographically fixed glomeruli in the antennal lobe. This convergence allows for the formation of an odotopic map in the antennal lobe whose organization could provide a basis for olfactory discrimination in Drosophila.

Infectivity of Moloney murine leukemia virus defective in late assembly events is restored by late assembly domains of other retroviruses

The p12 region of the Moloney murine leukemia virus (M-MuLV) Gag protein contains a PPPY motif important for efficient virion assembly and release. To probe the function of the PPPY motif, a series of insertions of homologous and heterologous motifs from other retroviruses were introduced at various positions in a mutant gag gene lacking the PPPY motif. The assembly defects of the PPPY deletion mutant could be rescued by insertion of a wild-type PPPY motif and flanking sequences at several ectopic positions in the Gag protein. The late assembly domain (L-domain) of Rous sarcoma virus (RSV) or human immunodeficiency virus type 1 (HIV-1) could also fully or partially restore M-MuLV assembly when introduced into matrix, p12, or nucleocapsid domains of the mutant M-MuLV Gag protein lacking the PPPY motif. Strikingly, mutant viruses carrying the RSV or the HIV-1 L-domain at the original location of the deleted PPPY motif were replication competent in rodent cells. These data suggest that the PPPY motif of M-MuLV acts in a partially position-independent manner and is functionally interchangeable with L-domains of other retroviruses. Electron microscopy studies revealed that deletion of the entire p12 region resulted in the formation of tube-like rather than spherical particles. Remarkably, the PPPY deletion mutant formed chain structures composed of multiple viral particles linked on the cell surface. Many of the mutants with heterologous L-domains released virions with wild-type morphology.

Effects of simulated microgravity on immunoreactivity of conjugated-ubiquitin of muscle spindles of soleus in rats

It is well known that the muscle spindle is a receptor of muscle's tension and length, it plays an important role in maintaining the muscle's tension. The aim of the present study is to compare the cross-section area (CSA) and the immunoreactivity of conjugated-ubiquitin in soleus extrafusal and intrafusal fibers after simulated-microgravity in order to demonstrate the role of muscle spindle in muscle atrophy induced by simulated microgravity.

Linkage of a gene for familial hypobetalipoproteinemia to chromosome 3p21.1-22

Familial hypobetalipoproteinemia (FHBL) is an apparently autosomal dominant disorder of lipid metabolism characterized by less than fifth percentile age- and sex-specific levels of apolipoprotein beta (apobeta) and low-density lipoprotein-cholesterol. In a minority of cases, FHBL is due to truncation-producing mutations in the apobeta gene on chromosome 2p23-24. Previously, we reported on a four-generation FHBL kindred in which we had ruled out linkage of the trait to the apobeta gene. To locate other loci containing genes for low apobeta levels in the kindred, a genomewide search was conducted. Regions on 3p21.1-22 with two-point LOD scores >1.5 were identified. Additional markers were typed in the region of these signals. Two-point LOD scores in the region of D3S2407 increased to 3.35 at O = 0. GENEHUNTER confirmed this finding with an nonparametric multipoint LOD score of 7.5 (P=.0004). Additional model-free analyses were conducted with the square root of the apobeta level as the phenotype. Results from the Loki and SOLAR programs further confirmed linkage of FHBL to 3p21.1-22. Weaker linkage to a region near D19S916 was also indicated by Loki and SOLAR. Thus, a heretofore unidentified genetic susceptibility locus for FHBL may reside on chromosome 3.

Candidate tumor suppressor RIZ is frequently involved in colorectal carcinogenesis

The distal portion of chromosome 1p is one of the most commonly affected regions in human cancer. In this study of hereditary and sporadic colorectal cancer, a region of frequent deletion was identified at 32.2 centimorgans from 1ptel. Deletion breakpoints clustered in the vicinity of or inside the gene RIZ, which encodes a retinoblastoma protein-interacting zinc finger protein. Sequence analysis revealed frequent frameshift mutations of the RIZ gene. The mutations consisted of 1- or 2-bp deletions of a coding (A)(8) or (A)(9) tract and were confined to microsatellite-unstable colorectal tumors, being present in 9 of 24 (37.5%) primary tumors and in 6 of 11 (54.5%) cell lines; in 2 cell lines the mutation was homozygous/hemizygous. The mutations apparently were selected clonally in tumorigenesis, because similar poly(A) tracts in other genes were not affected. Two alternative products of the gene exist, RIZ1, which contains a PR (PRDI-BF1-RIZ1) domain implicated in tumor suppressor function, and RIZ2, which is lacking this motif. Furthermore, the C-terminal region, which contains the poly(A) tracts, includes a PR-binding motif, possibly mediating interactions with other proteins or with RIZ itself (oligomerization). Four of eleven microsatellite-unstable colorectal cancer cell lines, three of which had frameshifts, showed reduced or absent mRNA expression of RIZ1. In a cell line that is homozygous/hemizygous for the typical frameshift mutation, immunoblotting showed truncated RIZ protein, whereas adenovirus-mediated RIZ1 expression caused G(2)/M arrest and apoptosis. We propose that RIZ is a target of the observed 1p alterations, with impairment of the PR domain-mediated function through either frameshift mutation or genomic deletion.

A novel DNA element mediates transcription of Nkx2.1 by Sp1 and Sp3 in pulmonary epithelial cells

NKX2.1 is a member of the NK2 family of homeodomain-containing transcription factors whose targeted disruption in mouse results in the absence of thyroid tissue and a severely abnormal lung phenotype. Little is known regarding the mechanisms that control tissue and temporal specificity of Nkx2.1 gene expression. The Nkx2.1 gene has been cloned from a number of species and it is composed of three exons and two introns. Two distinct DNA domains located 5' of exon I and within intron I have been found to exhibit promoter activity in lung and thyroid cells. In the current study we used deletional analysis of the 5' flanking region of exon I and identified a 300 bp TATA-less region that exhibits significant promoter activity in H441 cells. The DNA sequence of this region contains multiple palindromes, composed of G/C-rich elements. DNase I footprinting demonstrates that this promoter region interacts with nuclear factors present in H441 cells. In particular electrophoretic mobility shift assay using antibodies against the Sp family members show that both Sp1 and Sp3 as well as an as yet unknown H441-specific factor interact with the palindromic structure within this promoter region. Co-transfection studies show that this promoter region responds to Sp1 and Sp3 and mutations therein result in a significantly diminished response to these transcriptional factors. Therefore, we have identified a novel DNA structure on the Nkx2.1 gene which participates in transcription of this gene in pulmonary epithelial cells by Sp1 and Sp3 transcription factors.

[Pot experiment on effect of clipping at seedling stage on spring wheat]

Pot experiment on the compensatory effects of spring wheat(Triticum aestivum) at different clipping intensities (simulating herbivory) at seedling stage (three leaves) was conducted in semiarid region of Gansu Province. Under two conditions of 60% and 90% of field water-holding capacity, spring wheat growth was stimulated by clipping at seedling stage, resulting in overcompensation in biological and economic yields, and with more compensation for heavy clipping than light clipping. The overcompensation of the spring wheat was at the cost of more water consumption.

Inhibition of distal lung morphogenesis in Nkx2.1(-/-) embryos

In vitro and in vivo results are consistent with a critical role for NKX2.1, an epithelial homeodomain transcription factor in lung morphogenesis. Nkx2.1 null mutant embryos die at birth due to respiratory insufficiency caused by profoundly abnormal lungs. However, the precise role of NKX2.1 in the multistep process of lung structural morphogenesis and differentiation of various pulmonary cell types remains unknown. In the current study, we tested the hypothesis that the mutant lungs do not undergo branching morphogenesis beyond the formation of the mainstem bronchi and therefore consist solely of dilated tracheobronchial structures. To test this hypothesis, we determined the spatial and temporal expression pattern of a number of extracellular matrix (ECM) proteins and their cellular receptors, including alpha-integrins, laminin, and collagen type IV. Although laminin is expressed in the mutant Nkx2.1(-/-) lungs, expression of alpha-integrins and collagen type IV is significantly reduced or absent. In addition, examination of regionally specific expression of differentially spliced Vegf (vascular endothelial growth factor) transcripts, clearly indicates that the epithelial phenotype of the Nkx2.1(-/-) lungs is similar to the tracheobronchial epithelium. In contrast to wild-type lungs in which both Vegf1 and Vegf3 are developmentally expressed, Nkx2.1(-/-) lungs are characterized by predominant expression of Vegf1 and reduced or absent Vegf3. A similar pattern of Vegf expression is also observed in isolated tracheo-bronchial tissue. The sum of these findings suggest that at least two separate pathways may exist in embryonic lung morphogenesis: proximal lung morphogenesis is Nkx2.1 independent, while distal lung morphogenesis appears to be strictly dependent on the wild-type activity of Nkx2.1.

Chronic blockade of brain "ouabain" prevents sympathetic hyper-reactivity and impairment of acute baroreflex resetting in rats with congestive heart failure

In rats with congestive heart failure (CHF) post myocardial infarction (MI) acute blockade of brain "ouabain" reverses sympathetic hyperactivity and chronic blockade prevents the desensitization of baroreflex function. This study was conducted to determine: i) if chronic blockade of brain "ouabain" maintains normal sympathetic reactivity; and ii) if acute baroreflex resetting (another parameter of baroreflex function) also becomes impaired, and if so, does brain "ouabain" contribute to impairment in acute baroreflex resetting. CHF post MI was induced by acute coronary artery ligation in Wistar rats. Animals were treated with 200 microg x day(-1) i.c.v. or i.v. Fab fragments (which bind brain "ouabain" with high affinity), or treated with 200 microg x day(-1) i.c.v. gamma-globulins (control group). The length of treatment was 0.5-8 weeks or 4-8 weeks post MI. At 8 weeks mean arterial pressure (MAP), central venous pressure (CVP), heart rate (HR), and renal sympathetic nerve activity (RSNA) were recorded in concious rats at rest and in response to: i) air-jet stress, ii) i.c.v. guanabenz (an alpha2-adrenoceptor agonist), and iii) a 30 min i.v. infusion of nitroprusside (NP). Excitatory responses to air stress and inhibitory responses to guanabenz of MAP, HR, and RSNA were significantly enhanced in rats with CHF versus the sham-operated treated group. This enhancement was prevented in the CHF group treated with i.c.v., but not i.v., Fab. Nitroprusside induced a sustained decrease in MAP (approximately 25 mmHg) and a transient decrease in CVP. Heart rate and RSNA increased significantly within 1 min of beginning the infusion. The peak increases as well as the product of changes in MAP-HR and RSNA-HR were significantly smaller in rats with CHF treated with gamma-globulins versus sham rats and versus CHF rats treated with i.c.v. Fab. In sham-operated rats and CHF rats treated with i.c.v. Fab, RSNA and HR began to decrease within 3-4 min of beginning the NP infusion and had returned to baseline by 20 min. In contrast, RSNA and HR remained increased throughout the infusion in the CHF rats treated with gamma-globulins. These data indicate that in rats with CHF acute resetting of the arterial baroreflex in response to a lower BP becomes impaired, and chronic blockade of brain "ouabain" prevents both this change in baroreflex resetting as well as sympathetic hyperactivity.

Characterization of a novel member of the DOK family that binds and modulates Abl signaling

A novel member of the p62(dok) family of proteins, termed DOKL, is described. DOKL contains features of intracellular signaling molecules, including an N-terminal PH (pleckstrin homology) domain, a central PTB (phosphotyrosine binding) domain, and a C-terminal domain with multiple potential tyrosine phosphorylation sites and proline-rich regions, which might serve as docking sites for SH2- and SH3-containing proteins. The DOKL gene is predominantly expressed in bone marrow, spleen, and lung, although low-level expression of the RNA can also be detected in other tissues. DOKL and p62(dok) bind through their PTB domains to the Abelson tyrosine kinase in a kinase-dependent manner in both yeast and mammalian cells. DOKL is phosphorylated by the Abl tyrosine kinase in vivo. In contrast to p62(dok), DOKL lacks YxxP motifs in the C terminus and does not bind to Ras GTPase-activating protein (RasGAP) upon phosphorylation. Overexpression of DOKL, but not p62(dok), suppresses v-Abl-induced mitogen-activated protein (MAP) kinase activation but has no effect on constitutively activated Ras- and epidermal growth factor-induced MAP kinase activation. The inhibitory effect requires the PTB domain of DOKL. Finally, overexpression of DOKL in NIH 3T3 cells inhibits the transforming activity of v-Abl. These results suggest that DOKL may modulate Abl function.

Brain "ouabain" and angiotensin II contribute to cardiac dysfunction after myocardial infarction

In chronic heart failure (CHF), sympathetic activity increases in parallel with the impairment of left ventricle (LV) function, and sympathetic hyperactivity has been postulated to contribute to the progression of heart failure. In the brain, compounds with ouabain-like activity ("ouabain," for brevity) and the renin-angiotensin system contribute to sympathetic hyperactivity in rats with CHF after myocardial infarction (MI). In the present studies, we assessed whether, in rats, chronic blockade of brain "ouabain" or the brain renin-angiotensin system inhibits the post-MI LV dysfunction. In rats, an MI was induced by acute coronary artery ligation. At either 0.5 or 4 wk post-MI, chronic treatment with Fab fragments for blocking brain "ouabain" or with losartan for blocking brain AT(1) receptors was started and continued until 8 wk post-MI using osmotic minipumps connected to intracerebroventricular cannulas. At 8 wk post-MI, in conscious rats, LV pressures were measured at rest and in response to volume and pressure overload, followed by LV passive pressure-volume curves in vitro. At 8 wk post-MI, control MI rats exhibited clear increases in LV end-diastolic pressure (LVEDP) at rest and in response to pressure and volume overload. LV pressure-volume curves in vitro showed a marked shift to the right. Intravenous administration of the Fab fragments or losartan at rates used for central blockade did not affect these parameters. In contrast, chronic central blockade with either Fab fragments or losartan significantly lowered LVEDP at rest (only in 0.5- to 8-wk groups) and particularly in response to pressure or volume overload. LV dilation, as assessed from LV pressure-volume curves, was also significantly inhibited. These results indicate that chronic blockade of brain "ouabain" or brain AT(1) receptors substantially inhibits development of LV dilation and dysfunction in rats post-MI.

Comparison of heteroduplex analysis, direct sequencing, and enzyme mismatch cleavage for detecting mutations in a large gene, FBN1

Analysis of large genes for mutations of clinical relevance is complicated by intragenic heterogeneity, sensitivity, and cost of the methods available, and in the case of many conditions, specificity of the genetic alterations detected. We examined the FBN1 gene for mutations in people who had Marfan syndrome using three methods: single-chain polymorphism analysis (SSCP) with heteroduplex (HA) analysis, enzyme-mediated cleavage (EMC) of heteroduplexes, and direct sequencing. We also used these methods to search for mutations in the P53 gene in patients with hepatocellular carcinoma. The results showed that EMC was most efficient for detecting mutations. However, the cost favored SSCP with heteroduplex analysis, provided conditions did not need to be optimized to detect a mutation. Until more cost-effective and sensitive methods are developed to detect unknown mutations in large genes, diagnosis of many genetic disorders will depend on the willingness of an investigator who is studying a particular disorder to perform clinical molecular testing and have the laboratory accredited.

[A new explanation for shadow bands on denaturing PAGE for products of STRS--the difference between sense and antisense strands in electrophoresis]

OBJECTIVE

To explore the mechanism of shadow bands on denaturing PAGE for PCR products of STR sequences and try to eliminate them.

METHODS

PCR and asymmetric PCR were employed. The amplified fragments were separated on denaturing PAGE and visualized by silver stain.

RESULTS

By asymmetric PCR, half of shadow bands of dinucleotide repeats were eliminated and there was only one band for each allele for tetranucleotide sequence. A different migration between the sense strand and antisense strand was identified.

CONCLUSION

The difference between sense and antisense strands in electrophoresis is one of the causes in shadow bands, and these shadow bands can be eliminated by asymmetric PCR partly or totally.

Mutations altering the moloney murine leukemia virus p12 Gag protein affect virion production and early events of the virus life cycle

The p12 Gag protein of Moloney murine leukemia virus is a small polypeptide of unknown function, containing two proline-rich motifs. To determine its role in replication, we introduced a series of deletion and alanine-scanning substitution mutations throughout the p12 coding region of a proviral DNA, and characterized the phenotypes of the resulting mutant viruses. Complete deletion of p12 and mutations affecting the PPPY motif caused substantial reduction in the yield of virions and a modest reduction in Gag processing. Proteolytic cleavage of the R-peptide from the cytoplasmic tail of the envelope protein TM was abolished in these mutants, suggesting that the PPPY motif is crucial for the viral protease to access the TM tail. The resulting virions were non-infectious, and unable to initiate DNA synthesis in infected cells. Mutants with alterations in both the N- and C-terminal portions of p12 exhibited a distinct phenotype. The production of virions and processing of Gag, Pol and Env precursors were normal. The viruses were able to direct synthesis of linear viral DNA, but there was almost no detectable circular DNAs or LTR-LTR junction. These data suggest that p12 plays a critical role in the early events of the virus life cycle.