Neuralgia del trigémino clásica familiar / Familial classic trigeminal neuralgia

Introducción: La neuralgia del trigémino clásica es un cuadro habitualmente esporádico, sin asociación familiar. Pero se estima que hasta un 2% de las neuralgias del trigémino podrían ser de tipo familiar. La caracterización de esta entidad es de utilidad para su identificación e incluso podría ser clave para definir las causas subyacentes en la neuralgia del trigémino clásica esporádica. Por esta razón, se aporta una serie de 5 familias en las que al menos existen 2 familiares con este cuadro, constituyendo un total de 11 casos. Material y métodos: Se recogieron casos familiares entre marzo del 2014 y marzo del 2015, interrogando sistemáticamente a los pacientes que acudían a la consulta de Neurología general con el diagnóstico de neuralgia del trigémino. Resultados: La neuralgia del trigémino clásica familiar afecta predominantemente a mujeres, la edad media de inicio es de 62,9 ± 13,93 años, es más frecuente la afectación de V2 y la edad de presentación es más temprana en la siguiente generación. La mayoría responde al tratamiento farmacológico. La respuesta al tratamiento neuroquirúrgico no es efectiva en todos los casos. Conclusiones: Estas agrupaciones familiares apoyan la idea de probables implicaciones genéticas en el desarrollo de este cuadro. Se postulan como posibles causas: conformaciones anatómicas heredadas en la estructura de la base del cráneo que facilitarían la compresión del trigémino por estructuras vasculares; HTA familiar responsable de formar vasos tortuosos que comprimirían el nervio trigémino; o alteraciones genéticas en la codificación de canales de calcio que provocarían su hiperexcitabilidad. Se sugiere una forma de herencia autosómica dominante con fenómeno de anticipación

Introduction: The classic form of trigeminal neuralgia is usually sporadic (no familial clustering). However, around 2% of all cases of trigeminal neuralgia may be familial. Describing this entity may be useful for diagnosing this process and may also be key to determining the underlying causes of sporadic classical trigeminal neuralgia. We report on cases in a series of 5 families with at least 2 members with classic trigeminal neuralgia, amounting to a total of 11 cases. Material and methods: We recorded cases of familial classical trigeminal neuralgia between March 2014 and March 2015 by systematically interviewing all patients with a diagnosis of trigeminal neuralgia who visited the neurology department on an outpatient basis. Results: In our sample, most patients with familial classic trigeminal neuralgia were women. Mean age at onset was 62.9 ± 13.93 years, decreasing in subsequent generations. V2 was the most frequently affected branch. Most of our patients responded well to medical treatment, and surgery was not effective in all cases. Conclusions: These family clusters support the hypothesis that classic trigeminal neuralgia may have a genetic origin. Several causes have been suggested, including inherited anatomical changes affecting the base of the skull which would promote compression of the trigeminal nerve by vascular structures, familial AHT (resulting in tortuous vessels that would compress the trigeminal nerve), and mutations in the gene coding for calcium channels leading to hyperexcitability. Classic trigeminal neuralgia may be an autosomal dominant disorder displaying genetic anticipation

Familial classic trigeminal neuralgia. / Neuralgia del trigémino clásica familiar.

INTRODUCTION: The classic form of trigeminal neuralgia is usually sporadic (no familial clustering). However, around 2% of all cases of trigeminal neuralgia may be familial. Describing this entity may be useful for diagnosing this process and may also be key to determining the underlying causes of sporadic classical trigeminal neuralgia. We report on cases in a series of 5 families with at least 2 members with classic trigeminal neuralgia, amounting to a total of 11 cases. MATERIAL AND METHODS: We recorded cases of familial classical trigeminal neuralgia between March 2014 and March 2015 by systematically interviewing all patients with a diagnosis of trigeminal neuralgia who visited the neurology department on an outpatient basis. RESULTS: In our sample, most patients with familial classic trigeminal neuralgia were women. Mean age at onset was 62.9±13.93 years, decreasing in subsequent generations. V2 was the most frequently affected branch. Most of our patients responded well to medical treatment, and surgery was not effective in all cases. CONCLUSIONS: These family clusters support the hypothesis that classic trigeminal neuralgia may have a genetic origin. Several causes have been suggested, including inherited anatomical changes affecting the base of the skull which would promote compression of the trigeminal nerve by vascular structures, familial AHT (resulting in tortuous vessels that would compress the trigeminal nerve), and mutations in the gene coding for calcium channels leading to hyperexcitability. Classic trigeminal neuralgia may be an autosomal dominant disorder displaying genetic anticipation.

Fatal familial insomnia: clinical, neuropathological, and genetic description of a Spanish family.

The clinical presentation and evolution, neuropathological findings, and genotyping of three members of a Spanish family affected with fatal familial insomnia are reported. The mother and two of her offspring developed a rapidly evolving disease with insomnia and behavioural disorders as the initial symptoms and died between 5 and 10 months after the onset of the illness. Frontal brain biopsy in the mother disclosed only non-significant spongiosis, and full neuropathological examination of her offspring showed thalamic and olivary degeneration with isolated focal cortical spongiosis. Genetic examination could only be performed in the contemporary patients and both harboured the prion protein (PrP) 178Asn mutation and homozygous 129 Met/Met genotype.

[Side effects of antithrombotic treatment in the secondary prevention of cerebrovascular disease]. / Efectos secundarios del tratamiento antitrombótico en la prevención secundaria de la enfermedad cerebrovascular.

OBJECTIVE: To determine the incidence of adverse effects of antithrombotic drugs (platelet anti-aggregants and anticoagulants) in patients with transient ischemic attacks (TIA) and mild ischemic strokes (IL). PATIENTS AND METHODS: Clinical follow-up data on the patients with TIA and IL included in a community-based observational study undertaken in the province of Segovia. Adverse effects which led to suspension of treatment or were a potential danger for the patient's life were recorded. RESULTS: The groups studied included 235 patients and the average initial age was 70.8 years. The average follow-up time was 3.6 years. The treatment initially given included: aspirin (75.7%), ticlopidine (12.8%) and acenocumarol (9.4%). Adverse effects led to suspension of treatment in 6% (5% with aspirin and acenocumarol, 17% with ticlopidine). The adverse effects of ticlopidine were mild and patients did not need admission to hospital (cutaneous exanthema, diarrhoea and reversible leucopenia). Aspirin was associated with digestive tract bleeding (2.8%) and cerebral hemorrhage (1.7%) which required hospital admission in most cases. One patient treated with acenocumarol presented with a retroperitoneal hematoma. CONCLUSIONS: In general antithrombotic drugs are well-tolerated by patients with TIA and LI. Hemorrhagic complications, particularly of the digestive tract, associated with aspirin limit tolerance to it.

Efectos secundarios del tratamiento antitrombótico en la prevención secundaria de la enfermedad cerebrovascular / Side effects of antithrombotic treatment in the secondary prevention of cerebrovascular disease

Objetivo. Determinar la incidencia de efectos adversos de los fármacos antitrombóticos (antiagregantes plaquetarios y anticoagulantes) en pacientes con accidentes isquémicos transitorios (AIT) e ictus isquémicos leves (IL). Pacientes y métodos. Seguimiento clínico de los pacientes con AIT e IL incluidos en un estudio observacional de base comunitaria desarrollado en la provincia de Segovia.Se registraron los efectos adversos que obligaron a suspender el tratamiento o con potencial peligro para la vida del paciente. Resultados. El grupo de estudio incluía 235 pacientes y la edad media inicial era de 70,8 años. El tiempo medio de seguimiento fue de 3,6 años. Los tratamientos utilizados inicialmente fueron: aspirina (75,7 por ciento), ticlopidina (12,8 por ciento) y acenocumarol (9,4 por ciento). El 6 por ciento de los pacientes tuvieron que suspender el tratamiento por efectos adversos (5 por ciento con aspirina y acenocumarol, 17 por ciento con ticlopidina). Los efectos adversos de la ticlopidina fueron leves y no requirieron hospitalización (exantema cutáneo, diarrea y leucopenia reversible). La aspirina se asoció a hemorragias digestivas (2,8 por ciento) y cerebrales (1,7 por ciento) que requirieron hospitalización en la mayoría de los casos.Un paciente en tratamiento con acenocumarol presentó un hematoma retroperitoneal. Conclusiones. Los fármacos antitrombóticos son en general bien tolerados por los pacientes con AIT e IL. Las complicaciones hemorrágicas, especialmente digestivas, asociadas a la utilización de aspirina limitan su buena tolerancia (AU)

[Diagnosis of transmissible spongiform encephalopathies in Spain. Population perspective]. / Diagnóstico de las encefalopatías espongiformes transmisibles en España desde una perspectiva poblacional.

OBJECTIVES: To describe specific aspects of the diagnostic process of transmissible spongiform encephalopathies in Spain and to evaluate the 14-3-3 protein test in cerebrospinal fluid. METHODS: The annual pattern of diagnostic certainty as well as those of demand and results of biochemical and genetic studies were studied using two sets of patients, those diagnosed for the 1993-1998 period, notified to a National Creutzfeldt-Jakob Disease Register (NCDJR), and those referred to the Tissue Bank for Neurological Research Laboratory (TBNRL). The 14-3-3 protein test was validated taking as a reference two clinical populations. RESULTS: Two-hundred and four Creutzfeldt-Jakob disease cases were registered at the NCDJR: 39 out of them and 28 other patients had been studied at the TBNRL. The proportion of definite Creutzfeldt-Jakob Disease cases decreased since 1996. Among those registered in 1997-1998, 35.5%, 36% and 20% had undergone 14-3-3 protein in LCR, histopathologic and genetic studies. The 14-3-3 test grave, for definite, sporadic Creutzfeldt-Jakob disease as compared for patients with other dementing disorders, the following data: 12/13 sensitivity; 33/35 specificity; and 12/14 and 33/34 predictive values of positive and negative test. Two familial cases were diagnosed by identification of mutations in the TBNRL. CONCLUSIONS: The results suggest that: a) the diagnostic certainty of Creutzfeldt-Jakob disease in Spain decreased due to a drop in autopsy rates; b) the 14-3-3 cerebrospinal fluid test has a high diagnostic value, and its use diffused rapid but incompletely; c) genetic studies are useful in some cases, and d) Creutzfeldt-Jakob disease undereporting may be considerable. Creutzfeldt-Jakob disease diagnosis and surveillance, are closely related and being consolidated in Spain.

Identification of novel import and export signals of human TAP, the protein that binds to the constitutive transport element of the type D retrovirus mRNAs.

The nuclear export of the unspliced type D retrovirus mRNA depends on the cis-acting constitutive transport RNA element (CTE) that has been shown to interact with the human TAP (hTAP) protein promoting the export of the CTE-containing mRNAs. We report here that hTAP is a 619-amino-acid protein extending the previously identified protein by another 60 residues at the N terminus and that hTAP shares high homology with the predicted rat and mouse TAP proteins. We found that hTAP is a nuclear protein that accumulates in the nuclear rim and the nucleoplasm. We further demonstrated that hTAP is able to shuttle between the nucleus and the cytoplasm. Identification of the signals responsible for nuclear import (NLS) and export (NES) revealed that they are distinct but partially overlapping. NLS and NES of hTAP are active transferable signals that do not share similarities with known elements. The C-terminal portion contributes further to hTAP's nuclear retention and contains a signal(s) for nuclear rim association. Taken together, our data show that hTAP is a dynamic protein capable of bidirectional trafficking across the nuclear envelope. These data further support hTAP's role as an export factor of the CTE-containing mRNAs.

Clinical genetics of familial progressive supranuclear palsy.

Recent studies have shown that progressive supranuclear palsy (PSP) could be inherited, but the pattern of inheritance and the spectrum of the clinical findings in relatives are unknown. We here report 12 pedigrees, confirmed by pathology in four probands, with familial PSP. Pathological diagnosis was confirmed according to recently reported internationally agreed criteria. The spectrum of the clinical phenotypes in these families was variable including 34 typical cases of PSP (12 probands plus 22 secondary cases), three patients with postural tremor, three with dementia, one with parkinsonism, two with tremor, dystonia, gaze palsy and tics, and one with gait disturbance. The presence of affected members in at least two generations in eight of the families and the absence of consanguinity suggests autosomal dominant transmission with incomplete penetrance. We conclude that hereditary PSP is more frequent than previously thought and that the scarcity of familial cases may be related to a lack of recognition of the variable phenotypic expression of the disease.

Implicit Theories versus the Social Construal of Ability in Self-Regulation and Performance on a Complex Task.

The present experiment examined the relative impacts of implicit theories and the social construal of ability as either a fixed entity or an incremental skill on self-efficacy, affective reactions, self-set goals, and performance on a complex group-management task. It was also a novel task for participants. Participants who had an implicit theory that group-management ability is an incremental skill that can be acquired with experience developed stronger self-efficacy, maintained more positive affect, and set themselves more challenging goals across multiple trials. They also outperformed participants with a fixed-entity theory of group-management ability. Some of the motivational benefits of an incremental-skill conception were lost when the social construal of managerial ability emphasized a fixed-entity conception. However, the negative motivational effects of a fixed-entity theory of ability were not ameliorated by the social construal of managerial ability as an incremental skill. The effects of conceptions of ability were fully mediated by the self-regulatory responses of participants. The hypothesis that self-efficacy moderates the impact of ability conceptions on self-set goal challenges was not supported. Copyright 1999 Academic Press.

[Neurological complications of Mediterranean boutonneuse fever. Presentation of a case of acute encephalomeningomyelitis and review of the literature]. / Complicaciones neurológicas de la fiebre botonosa mediterránea. Presentación de un caso de encefalomeningomielitis aguda y revisión de la literatura.

Mediterranean spotted fever is an infectious disease due to Rickettsia conorii usually considered as benign; however, 10% of cases may have severe complications. We report a patient with celiac disease who developed encephalomeningomyelitis secondary to Mediterranean spotted fever. Meningoencephalitic involvement occurred during the acute phase, with myelitis appearing early during convalescence, as acute onset paraplegia involving the lumbosacral spinal cord. A magnetic resonance study showed multifocal white matter disturbances, with no lesions in the spinal cord. One month following onset, R. conorii antibodies serum level was 1/640. A cutaneous biopsy performed during the acute phase revealed endothelial hyperplasia, intraluminal thrombosis and lymphocytic perivascular infiltrate. Several immunological disturbances were found (circulating immune complexes, antinuclear antibodies, IgG paraproteinemia). The development of a systemic vasculitis is the major pathogenetic factor in the origin of systemic complications of Mediterranean spotted fever. We review the neurological syndromes reported in association with R. conorii infection. Our case is the second described as acute myelopathy complicating Mediterranean spotted fever.

Risk factors for levodopa-induced dyskinesias in Parkinson's disease.

To identify putative risk factors for levodopa-induced dyskinesias we studied the effect of several clinical variables on the occurrence of dyskinesias in a series of 168 consecutive patients with Parkinson's disease treated for at least 6 months with levodopa. Of these, 108 (64%) developed dyskinesias after a mean duration of levodopa treatment of 51.4 +/- 43.3 months. Patients tended to suffer dyskinesias on the side of the body first affected by Parkinson's disease. The overall probability of developing dyskinesias increased with levodopa treatment duration, about 10% per year during the first 7 years. Univariate and multivariate logistic regression analysis identified the age at onset of Parkinson's disease (OR 0.923; 95% CI 0.883-0.964) and the initial levodopa dose (mean dose of the first 6 months of treatment; OR 1.004; 95% CI 1.002-1.006) as the main independent predictors. Survival curves showed that onset of Parkinson's disease at age 50 years or before (logrank, P < 0.05) and initial levodopa treatment with more than 600 mg/day (logrank, P < 0.05) were associated with a higher risk for the appearance of dyskinesias.

TAP, the human homolog of Mex67p, mediates CTE-dependent RNA export from the nucleus.

The constitutive transport element (CTE) of the type D retroviruses promotes nuclear export of unspliced viral RNAs apparently by recruiting host factor(s) required for export of cellular messenger RNAs. Here, we report the identification of TAP as the cellular factor that specifically binds to wild-type CTE but not to export-deficient CTE mutants. Microinjection experiments performed in Xenopus oocytes demonstrate that TAP directly stimulates CTE-dependent export. Furthermore, TAP overcomes the mRNA export block caused by the presence of saturating amounts of CTE RNA. Thus, TAP, like its yeast homolog Mex67p, is a bona fide mRNA nuclear export mediator. TAP is the second cellular RNA binding protein shown to be directly involved in the export of its target RNA.

Identification of an RNA sequence within an intracisternal-A particle element able to replace Rev-mediated posttranscriptional regulation of human immunodeficiency virus type 1.

Human immunodeficiency virus type 1 (HIV-1) replication depends on the posttranscriptional regulation by the viral Rev protein and can be replaced with the posttranscriptional RNA control element (CTE) of the type D simian retroviruses. We have identified a sequence which shares only nucleotide sequences of the internal loops and secondary structure with the CTE and which is part of a novel murine intracisternal-A particle (IAP) retroelement, inserted within the transcribed mouse osteocalcin-related gene. This sequence, named CTE(IAP), can replace the Rev-mediated regulation of HIV-1, hence it is a posttranscriptional regulatory element. Related elements have been identified in other IAPs. These results suggest that insertional mutagenesis can affect gene expression by providing a functional posttranscriptional control element. The CTE(IAP) and CTEs of the type D simian retroviruses represent a novel class of RNA elements characterized by unique sequences within the internal loops which are predicted to represent the interaction site with cellular factor(s). These findings suggest that such elements may be involved in posttranscriptional regulation of cellular mRNAs.

Premorbid dietetic habits and risk for Parkinson's disease.

To evaluate the possible role of antioxidant (vitamins A, E, C, beta-carotene, zinc, selenium) or pro-oxidant (iron, copper, manganese) factors present in the diet, in the risk for Parkinson's disease (PD), we conducted a dietetic study (pre- and postmarriage) which included 91 foodstuffs. We interviewed separately 119 PD patients (64 males, 55 females, age 65.3 +/- 8.5 years, age at marriage 27.8 +/- 5.9 years) and their spouses (age 65.0 +/- 9.2 years, age at marriage 27.2 +/- 5.9 years) as the control group (C). Premarriage consumption for each foodstuff was classified into: (1) rarely of annually, (2) monthly, or (3) weekly; and postmarriage consumption (which included the period between age at marruage and age 40 years; only concordant answers were considered to be valid) into: (1) PD > Control, (2) Control > PD, and (3) PD = Control. The premarriage interview showed a trend towards a lower consumption of peas in PD patients as compared to controls. The postmarriage interview in PD patients showed a higher tendency for the consumption of rice, bluefish, liver paté and eggs, and a less consumption of tea than controls. We were unable to find any consistent trend towards a lower consumption of vitamins E and C during adulthood in PD patients, but they seemed to have eaten selenium-rich foodstuffs more frequently than controls. These results differ from those obtained by previous studies, and question the possible role of premorbid dietary habits on the risk for PD.

The posttranscriptional control element of the simian retrovirus type 1 forms an extensive RNA secondary structure necessary for its function.

It was previously shown that a 240-nucleotide (nt) RNA element (cis-acting transactivation element [CTE]) located between the env gene and the 3' long terminal repeat of simian retrovirus type 1 (SRV-1) can functionally replace posttranscriptional activation directed by Rev and the Rev-responsive element (RRE) when inserted into a Rev- and RRE-deficient molecular clone of human immunodeficiency virus type 1, resulting in efficient virus replication. Here, we analyze the molecular and structural requirements for function of this RNA element. Deletion mutagenesis demonstrated that the core element spans 173 nt. SRV-2 and Mason-Pfizer monkey virus have highly homologous elements, which function similarly when inserted into the Rev/RRE-deficient human immunodeficiency virus type 1. Computer prediction indicated that the core CTEs of all three viruses have similar extensive secondary structures. Mutagenesis of the SRV-1 CTE revealed that both sequence and secondary structure are essential for function. Nuclease probing of the SRV-1 CTE further supported the genetic analysis and confirmed the predicted structural features of the RNA element. Sequence analysis of the 240-nt SRV-1 CTE, after continuous long-term propagation of the Rev-independent viruses, revealed that the genetically defined core element remained unchanged, while regions outside the core CTE underwent deletions or duplications. These data further support our in vitro mutagenesis data and demonstrate the importance of the sequence and structure of the SRV-1 CTE for appropriate function.

Changes induced by ovariectomy on the acute effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in a model of rat poor metabolizer of debrisoquine.

The female 'dark-adapted' rat, an animal model of poor metabolizer of debrisoquine, is more susceptible to neurotoxic effects of 1,2,3,6-tetrahydropyridine (MPTP) than other rat species (extensive metabolizers). Since ovariectomy improves the ability for the 4-hydroxylation of debrisoquine in female 'dark-adapted' rats, we studied the acute effects of MPTP (three doses of 10, 20, and 30 mg/kg s.c., respectively, at 12 hour intervals) in ovariectomized and laparotomized female 'dark-adapted' rats to test whether ovariectomy prevents MPTP-induced neurotoxicity. We measured regional brain monoamine levels. MPTP-induced depletion of dopamine (DA) and its metabolites was more prominent in the striatum. Ovariectomy, by itself, reduced dopamine and serotonin (5-HT) and their metabolites in striatum in both control and MPTP-treated animals. Factorial analysis of the effects of ovariectomy and MPTP treatment by two-way ANOVA revealed that both experimental procedures reduced DA and 5-HT neurotransmission in the striatum while the combined effect of both treatments did not produce any significant change. In spite of its induction of monoamine depletion in intact animals, ovariectomy partially prevented MPTP-induced depletion of monoamines in the surviving rats, suggesting that changes in metabolic rates of debrisoquine induced by ovariectomy produce resistance to MPTP in 'dark-adapted' rats.

Effects of calcium antagonists on the dopamine system.

Calcium channel antagonists are drugs currently used in the treatment of neurological and cardiovascular disorders and occasionally produce parkinsonism and movement disorders as a side effect. We investigated the effects of calcium channel antagonists on the pharmacology of dopamine systems in vivo and in vitro. Flunarizine, cinnarizine, and diltiazem reduce the viability of dopamine-rich human neuroblastoma cells in vitro. These compounds plus verapamil, nifedipine, and nicardipine reduce 3H-spiperone binding to bovine striatal membranes, 3H-dopamine uptake, K(+)-induced 3H-dopamine release, and apomorphine-induced rotation, but not amphetamine-induced rotation, in 6-OH-dopamine-lesioned rats. Therefore, all calcium channel antagonists tested reduce dopamine neurotransmission in vitro and in vivo, whereas the evidence of toxicity for dopamine cells in vitro is restricted to flunarizine, cinnarizine, and diltiazem. The clinical relevance of these toxic effects may depend on several factors, including age, penetration across the blood-brain barrier, and types of calcium channels present in the different neuronal subtypes. On the other hand, the finding of dopamine-regulating properties not associated to neurotoxic effects in the dihydropyridines and verapamil provides new putative therapeutics tools for the treatment of neurologic disorders associated with dopamine hyperactivity.

Cloning and DNA sequencing of xyaA, a gene encoding an endo-beta-1,4-xylanase from an alkalophilic Bacillus strain (N137).

The gene xyaA encoding an alkaline endo-beta 1,4-xylanase from an alkalophilic Bacillus sp. strain (N137) isolated in our laboratory was cloned and expressed in Escherichia coli. The nucleotide sequence of a 1,656-bp DNA fragment containing xyaA was determined, revealing one open reading frame of 993 bp that encodes a xylanase (XyaA) of 39 kDa. This xylanase lacks a typical putative signal peptide, yet the protein is found in the Bacillus culture supernatant. In Escherichia coli, the active protein is located mainly in the periplasmic space. The xylanase activity of the cloned XyaA is an endo-acting enzyme that shows optimal activity at pH 8 and 40 degrees C. This activity is stable at a pH between 6 and 11. Incubations of XyaA at 40 degrees C for 1 h destroyed 45% of the activity.

Elements distinct from human immunodeficiency virus type 1 splice sites are responsible for the Rev dependence of env mRNA.

In the absence of the viral regulatory protein Rev, the human immunodeficiency virus type 1 gag/pol and env mRNAs are inefficiently expressed, since nucleocytoplasmic transport, stability, and polysomal loading are impaired. It has been suggested that splicing is necessary for Rev function and that the low expression of the unspliced and intermediate spliced mRNAs in the absence of Rev is associated with specific splice sites. Previous studies identified distinct RNA elements within the gag/pol region responsible for low expression that are not associated with splice sites. Here we study the determinants for Rev dependence of the authentic env mRNA. We demonstrate that upon removal of all the utilized splice sites, the env mRNA is still Rev dependent and Rev responsive for expression in human cells. We have identified several regions within the env mRNA that inhibit expression of a gag-env hybrid mRNA. Elimination of one of these elements, located within the Rev-responsive element, did not result in virus expression, supporting our model that several independently acting elements are responsible for the downregulatory effect. By analogy to the RNA elements within the gag/pol region, we propose that elements unrelated to utilized splice sites are responsible for the posttranscriptional regulation of env mRNA.

Cloning and DNA sequencing of bgaA, a gene encoding an endo-beta-1,3-1,4-glucanase, from an alkalophilic Bacillus strain (N137).

The gene bgaA encoding an alkaline endo-beta-1,3-1,4-glucanase (lichenase) from an alkalophilic Bacillus sp. strain N137, isolated in our laboratory, was cloned and expressed from its own promoter in Escherichia coli. The nucleotide sequence of a 1,416-bp DNA fragment containing bgaA was determined and revealed an open reading frame of 828 nucleotides. The deduced protein sequence consists of 276 amino acids and has a 31-amino-acid putative signal peptide which is functional in E. coli, in which the BgaA protein is located mainly in the periplasmic space. The lichenase activity of BgaA is stable between pH 6 and 12, it shows optimal activity at a temperature between 60 and 70 degrees C, and it retains 65% of its activity after incubation at 70 degrees C for 1 h. This protein is similar to some other lichenases from Bacillus species such as B. amyloliquefaciens, B. brevis, B. licheniformis, B. macerans, B. polymyxa, and B. subtilis. However, it has a lysine-rich region at the carboxy terminus which is not found in any other published lichenase sequence and might be implicated in the unusual biochemical properties of this enzyme. The location of the mRNA 5' end was determined by primer extension and corresponds to nucleotide 235. A typical Bacillus sigma A promoter precedes the transcription start site.