The caspase-generated fragments of PKR cooperate to activate full-length PKR and inhibit translation.

We have studied the involvement of receptor interacting protein kinase-1 (RIP1) and dsRNA-activated protein kinase (PKR) in external dsRNA-induced apoptotic and necrotic cell death in Jurkat T cell lymphoma. Our results suggest that RIP1 plays an imported role in dsRNA-induced apoptosis and necrosis. We demonstrated that contrary to necrosis, protein synthesis is inhibited in apoptosis. Here, we show that phosphorylation of translation initiation factor 2-alpha (eukaryotic initiation factor 2-alpha (eIF2-alpha)) and its kinase, PKR, occur in dsRNA-induced apoptosis but not in necrosis. These events are caspase-dependent and coincide with the appearance of the caspase-mediated PKR fragments, N-terminal domain (ND) and kinase domain (KD). Our immunoprecipitation experiments demonstrated that both fragments could independently co-precipitate with full-length PKR. Expression of PKR-KD leads to PKR and eIF2-alpha phosphorylation and inhibits protein translation, whereas that of PKR-ND does not. Co-expression of PKR-ND and PKR-KD promotes their interaction with PKR, PKR and eIF2-alpha phosphorylation and suppresses protein translation better than PKR-KD alone. Our findings suggest a caspase-dependent mode of activation of PKR in apoptosis in which the PKR-KD fragment interacts with and activates intact PKR. PKR-ND facilitates the interaction of PKR-KD with full-length PKR and thus the activation of the kinase and amplifies the translation inhibitory signal.

Tipping the balance between necrosis and apoptosis in human and murine cells treated with interferon and dsRNA.

Interferons enhance the cellular antiviral response by inducing expression of protective proteins. Many of these proteins are activated by dsRNA, a typical by-product of viral infection. Here we show that type-I and type-II interferons can sensitize cells to dsRNA-induced cytotoxicity. In caspase-8- or FADD-deficient Jurkat cells dsRNA induces necrosis, instead of apoptosis. In L929sA cells dsRNA-induced necrosis involves high reactive oxygen species production. The antioxidant butylated hydroxyanisole protects cells from necrosis, but shifts the response to apoptosis. Treatment with the caspase inhibitor benzyloxycarbonyl-Val-Ala-DL-Asp(OMe)-fluoromethylketone or overexpression of Bcl-2 prevent this shift and promote necrosis. Our results suggest that a single stimulus can initiate different death-signaling pathways, leading to either necrotic or apoptotic cell death. Inhibition of key events in these signaling pathways, such as caspase activation, cytochrome c release or mitochondrial reactive oxygen species production, tips the balance between necrosis and apoptosis, leading to dominance of one of these death programs.

[Clinical features and genetic analysis in a family with X-linked incomplete congenital stationary night blindness (CSNBi)]. / Particularités cliniques et analyse génétique dans une famille atteinte de cécité nocturne non progressive congénitale héréditaire liée au chromosome X dans sa forme incomplète (CSNBi).

PURPOSE: We describe particular clinical features in a three-generation family with X-linked CSNBi and present the genetic analysis. METHOD: The diagnosis of CSNBi was established on clinical and electrophysiological criteria. Polymorphic DNA markers of the Xp region were analyzed by fluorescent polymerase chain reaction. RESULTS: Clinical findings evidenced an atypical association of both myopia and hyperopia in the same brotherhood. The most interesting feature in this family was the observation of major worsening of the clinical shape between the first and the third generation of affected individuals. DNA analysis did not show significant linkage between the disease and markers of the Xp11-p21 region. Southern analysis did not show expansion of trinucleotide repeat CAG/CTG and CCG/CGG over the three generation. CONCLUSION: Haplotypic analysis together with clinical observations allow to exclude the existence of a myopia gene closely linked to the CSNB2 locus. The clinical anticipation observed in this family does not seem to be linked with trinucleotide repeat expansion CAG/CTG or CCG/CGG.

Linkage disequilibrium between the M470V variant and the IVS8 polyT alleles of the CFTR gene in CBAVD.

Congenital bilateral absence of the vas deferens (CBAVD) is a cause of male sterility mostly resulting from mutations in the cystic fibrosis transmembrane regulator (CFTR) gene. The most common defect is the 5T variant at the branch/acceptor site of intron 8, which induces high levels of exon 9 skipping leading to non-functional protein. However, this 5T variant has incomplete penetrance and variable expressivity, suggesting that some other regulatory factors may modulate the splicing of exon 9. To identify such factors, we report here the genetic analysis of a polymorphic locus, M470V, located in exon 10 of the CFTR gene in 60 patients with CBAVD, compared to a normal control population. The statistical analysis showed strong linkage disequilibrium between the 5T allele and the V allele of the M470V polymorphism in the CBAVD population, but not in the normal population. The V allele in a gene carrying 5T could, however, contribute to lowering the level of normal transcripts, as already suggested by in vitro transcriptional studies. These genetic findings, together with previous studies, suggest involvement of the M470V variant in the modulation of the splicing of exon 9 of the CFTR gene.

Genetic findings in congenital bilateral aplasia of vas deferens patients and identification of six novel mutatations. Mutations in brief no. 138. Online.

Congential bilateral aplasia of vas deferens (CBAVD), a form of male sterility, has been suggested to represent a "genital" form of cystic fibrosis (CF), as mutations in the CFTR gene have been identified in most patients with this condition. Interestingly, the 5T allele in intron 8 appeared to be the most frequent mutation associated with CBAVD. However, the molecular basis of CBAVD is not completely understood. We have analysed the complete coding and flanking CFTR sequences by PCR-DGGE in 64 men with CBAVD from southern France with the aim to list any sequence alteration. Fourty-two of the 64 patients (65.6%) had mutations on both copies of the CFTR gene, including one patient with two mutations in the same copy (DF508 + A1067T). The 5T allele was present in 21/64 cases (33%). Six of the 28 different mutations identified in this study had never been described previously, and appeared to be specific to CBAVD (P111L, M244K, A1364V, G544V, 2896insAG,-33G->A).

Blastogenesis dominant 1: a sequence with midline anomalies and heterotaxy.

Lateralization defect is a heterogeneous condition with different modes of transmission (autosomal recessive, dominant or X-linked). Here, we report on 3 additional families that contribute to the description of phenotypic anomalies of the autosomal dominant type. Phenotypic anomalies include: lateralization defects, cardiac malformations, diaphragmatic hernia, urologic and neurologic anomalies. We suggest calling this sequence BGD1 for blastogenesis dominant 1 because the deleterious effect probably occurs during blastogenesis and involves not only lateralization but other defects as well.

Hereditary bundle branch defect: right bundle branch blocks of different causes have different morphologic characteristics.

Hereditary bundle branch defect is an autosomal dominant genetic disease that, in a large Lebanese family, was mapped to the long arm of chromosome 19. Affected individuals have various combinations of conduction defects such as right bundle branch block, left or right QRS frontal-axis deviation, or atrioventricular blocks. We now further characterize this disease with the presentation of a two-decade follow-up and analysis of electrocardiographic features and mutation-carrier status. The conduction block may be overt in the first year of life, and among affected individuals, there is a worsening of the conduction block in 5% to 15% of cases, leading to complete atrioventricular block and possibly to sudden death. A group of individuals had QRS anomalies in right precordial leads such as rsr's', rss', or rSr', which may account for partial right bundle branch blocks. In this group, which we referred to as having an "r' pattern," 53% were actually mutation carriers, and 19% evolved toward a complete fascicular block. By contrast, mutation carriers with a normal electrocardiogram remained normal. The QRS morphologic appearance in the right precordial leads of affected individuals and r' pattern mutation carriers is notable for the absence or weakness of negative forces resulting in a rsR' or rR' morphology. In addition, an r' pattern is highly suggestive of a mutation carrier status in the presence of a broad r wave in aVR and s in V6 or a frontal-axis deviation. Finally, mutation carriers demonstrate a conduction block significantly more often in males than females (75% and 50%, respectively). This incomplete penetrance and slow evolution suggest that the actual prevalence of hereditary bundle branch defect is very much underestimated.

[Genetics of hereditary cardiopathies]. / Génétique des cardiopathies héréditaires.

Hypertrophic cardiomyopathy may be secondary to a mutation in the cardiac beta myosin heavy chain (14q11-q12), alpha tropomyosin (15q22), troponin T (1q32), protein C gene (11p11-q13) or in a non yet mapped gene. A X-linked dilated cardiomyopathy may be due to a mutation in the dystrophin gene (Xp21). The long QT syndrome may be secondary to a mutation in a potassium channel (7q35-36), an alpha subunit of the sodium channel gene (3p21) or in genes not yet identified (11p15.5, 4q25-q27). Marfan syndrome is associated to mutations in the fibrillin 1 gene (15q21.1) and a Marfan-like syndrome with not ocular anomalies was mapped to 3p24. Patients with Williams-Beuren syndrome have microdeletions in 7q11, whereas in the supravalvular aortic stenosis, the elastin gene which maps to the same region, is mutated. In Di George and Shprintzen syndromes but not in conotruncal malformations, microdeletions in 22q11 are observed. Heterotaxia can be transmitted by 3 types of mendelian inheritance (Xq24-q27.1). Finally, other diseases were mapped: Noonan and Holt-Oram syndromes (12q), isolated conduction blocks (19q13.3), arrhythmogenic right ventricular cardiomyopathy (14q23-q24), total anomalous pulmonary venous return (4p13-q12) and Osler-Weber-Rendu (9q33-q34.1, 3p22 and 12q1). In the near future, these incoming data will deeply modify the cardiovascular field.

Familial non-syndromic conotruncal defects are not associated with a 22q11 microdeletion.

Molecular studies have shown microdeletions in region q11 of chromosome 22 in nearly all patients with DiGeorge, velocardiofacial and conotruncal anomaly face syndromes (DGS, VCFS and CTAFS, respectively) and in a high percentage of non-syndromic familial cases of conotruncal defects (CTD). CTD account for roughly a fourth to a third of all non-syndromic congenital heart defects (CHD), thus, 22q11 could harbor a major genetic factor of CHD. We searched for a 22q11 microdeletion in familial cases of non-syndromic CTD. Thirty-six cases of various isolated CTD, that is without history of hypocalcemia, immune deficiency, absent thymus, and dysmorphic appearance, were selected. With 48F8, a cosmid probe localized in the smallest deleted region of the DiGeorge critical region (DGCR), we found no deletions by fluorescence in situ hybridization in these 36 affected individuals of 16 families with recurrent CTD. Moreover, D22S264, a microsatellite localized at the distal part of the largest deleted region, was used to genotype the patients. Thirty-two patients out of 37 were heterozygous and hence not deleted at this locus, whereas 5 were uninformative. In conclusion, there are no large deletions in familial cases of various CTD, whether these defects are identical or not within a family. This result does not rule out other minor anomalies in this chromosomal region.

An isolated cardiac conduction disease maps to chromosome 19q.

Isolated cardiac conduction disease is an autosomal dominant defect that includes various combinations of bundle branch or fascicular blocks. These defects can cause sudden death due to a complete heart block. We used a genome-wide screening approach with polymorphic (CA)n repeat markers to determine the chromosomal position of the gene defect implicated in this disorder. The analyses were carried out on a large Lebanese kindred, which included individuals with either a complete or incomplete right bundle branch block (RBBB) with a vertical-axis deviation (< or = -30 or > or = +100). Linkage to the disease locus was detected with the polymorphic marker D19S604 on the q arm of chromosome 19 (19q13.3) with a multipoint lod score of 7.18. Additionally, we were able to exclude the flanking loci D19S606 and D19S571, which are 13 cM apart because of recombination events in three affected individuals. The histidine-rich calcium-binding protein gene is found in this region and is an attractive candidate gene on the basis of its physiological properties and a tight linkage. There is no expansion in two exon 1 regions known for a variable number of triplet repeats.

Evidence of two genetic entities in Bothriocephalus funiculus (Cestoda) detected by arbitrary-primer polymerase chain reaction random amplified polymorphic DNA fingerprinting.

The genetic diversity of two samples of Cestoda (Bothriocephalus funiculus, Renaud and Gabrion, 1984) parasitizing two sympatric teleostean species was assessed using random amplified polymorphic DNA (RAPD). A total of 72 Bothriocephalus were analyzed individually, and electrophoretic analysis of the amplification products of 65 primers among the 68 tested revealed monomorphic patterns, reflecting the close genetic relatedness within and between the parasites of the two samples. However, 3 primers showed polymorphic patterns at 6 RAPD sites. Analysis of the distribution of these genomic fragments, assuming random mating, showed strong linkage disequilibria (only 8 genetic combinations were observed among the 32 expected). Two genetic entities displaying a high degree of host specificity were evidenced within our two samples of funiculus. This powerful molecular technique can be used as a diagnostic tool in studies concerning the biodiversity of related genetic entities and could have broad applications in parasitology.

Deciphering the molecular genetics of congenital heart disease.

Congenital heart diseases are starting to benefit from the major advances provided by the advent of molecular biology methods. It is now possible to identify genes which are responsible for congenital heart diseases. The gene responsible for supravalvular aortic stenosis--an autosomal dominant trait--was cloned last year. It is the elastin gene. DiGeorge and Shprintzen syndromes, conotruncal anomaly face and some cardiac malformations have a common cause: a deletion of the 22q11 region resulting in a monosomy. Although the region of deletion is large, it is possible that monosomy of only one gene results in these conditions. Studies are underway to evaluate the impact of this new genetic factor on the incidence of congenital heart malformations. Studies on familial bundle branch block, and lateralization defect with midline anomalies are soon going to show a chromosomal region with the gene defect. Discovering the genes and their protein products which are implied in the cardiac morphogenesis will definitively change our understanding of these cardiac malformations.

[Mice SI/Col: a study model in the research of genes involved in situs inversus]. / La souris SI/Col: un modèle d'étude dans la recherche des gènes impliqués dans le situs inversus.

The SI/Col mouse is carrier of the i.v. mutation which expresses itself in an autosomal recessive mode. Fifty per cent of mice born of homozygotic i.v./i.v. parents are normal and 50% present an abnormality of lateralisation of the thoracic and abdominal organs with cardiac malformations involving the venous, atrial, ventricular and arterial segments. Identifying the i.v. mutation may improve our understanding of the genesis of the heterotaxic syndrome in man. With the help of return crossing with wild mice, the authors studied segregation of 10 makers of the murine, chromosome 12 of the situs inversus mice. The genetic map constructed from this data places the i.v. mutation near the telomeric extremity of the murine chromosome 12. Given the inter-species conservation between this region and the telomeric region of the human chromosome 14, it is a candidate region for the search of a homologous human gene in syndromes of heterotaxis.

A detailed linkage map of subtelomeric murine chromosome 12 region including the situs inversus mutation locus IV.

A mouse model is an invaluable tool to tackle genesis of human congenital diseases that have so far eluded human studies. Homozygote for the i.v. mutation, the murine Si/Col strain presents a left-right lateralization defect of thoracic and abdominal organs and heart defects very similar to human ones. This i.v. mutation has been mapped to the region between the Aat and Igh-C loci, suggesting the presence of an equivalent human gene in the human syntenic 14q3 region. A precise linkage map of the region is, therefore, of great interest since it will contribute to the genetic approach of the i.v. gene. Analysis of 242 back-cross progeny from Mus musculus (MAI) or spretus strains of mice and SI/Col mice has allowed mapping of the i.v. gene to a linkage group of eight markers. It includes four genes: Aat (alpha 1-antitrypsin), Ckb (creatine kinase, brain form), Crip (cysteine-rich intestinal protein), and Igh-C (immunoglobulin heavy chain constant region complex); three murine microsatellites: D12Mit6, D12Mit7, and D12Mit8; and one new marker, D12Mtp1, defined by a minisatellite human probe, pYNZ2. After analysis of the data by the LINKAGE program, the following multilocus map has been constructed: centromere-D12Mit6-6.9 cM-D12Mit7-1.7 cM-D12Mtp1-2.6 cM-Aat-5.0 cM-(Ckb, Igh-C)-0.4 cM-D12Mit8-0.4 cM-Crip-11.2 cM-i.v.-telomere. This map differs from the previous map in placing i.v. locus telomeric to Igh-C. D12Mit6 and D12Mit7 are now precisely mapped centromeric to the locus Aat. In addition, a new locus D12Mtp1 is located between Aat and D12Mit7.

[Ventriculo-cardiac derivation in late complications of hemispherectomy (author's transl)]. / La dérivation ventriculo-cardiaque dans les complications tardives de l'hémisphérectomie.

After briefly stating the circumstances in which hemispherectomy is indicated the authors review the possible complications of the operation on the basis of available literature. Two cases are described, one with autopsy findings and the other with CAT scan data which revealed extreme dilatation of the remaining ventricle and led to the installation of a ventriculo-cardiac derivation; this case progressed favourably. The author concludes that this type of complication could be detected rapidly by CAT scanning, with no risk to the patient. Ventriculo-cardiac derivation could prevent further complications. Hemispherectomized patients must undoubtedly be monitored closely by regular clinical examinations, EEGs and CAT scanning.

The management of anterior sacral meningocele with computed tomography.

This report concerns a case of anterior sacral meningocele (ASM) with an evaluation of the diagnostic reliability of the CT scan for the management of this condition and others concerning the vertebral column and pelvis. This technic makes a precise preoperative survey possible by the direct demonstration of the lesion and its extension, by the measurement of its density and by the visualization of its pedicle, as well as easy and atraumatic postoperative control. ASM is a congenital meningeal cyst, herniating through a bony defect of the sacrum. It often remains undetected, since it is a rather rare condition and difficult to visualize with simple diagnostic procedures. An early diagnosis of this basically benign condition is nevertheless very important, because of the serious pitfalls that may arise.