Wide range of disease onset in a family with Alzheimer disease and a His163Tyr mutation in the presenilin-1 gene

The tetraruthenated porphyrin, mu-[meso-5,10,15,20-tetra(pyridyl)porphyrin]tetrakis[bis-(bipyridine) chloride ruthenium(II)] (TRP) is a supramolecular cationic species. The aim of the present investigation was to evaluate the photodynamic properties of TRP and Zn-TRP to damage DNA with emphasis on the mechanistic aspects. The ability for tetraruthenated porphyrin derivatives to induce photosensitization reactions has been determined using 2'-deoxyguanosine as a DNA model compound. The main photooxidation products of the targeted nucleoside were identified and classified according to their mechanisms of formation, involving either a radical pathway (type I) or a singlet oxygen-mediated mechanism (type II). Quantification of the different oxidation products provides a means to evaluate the relative contribution of type I and type II pathways associated with the oxidative photosensitization of 2'-deoxyguanosine by tetraruthenated porphyrin derivatives. Results indicate that 1O2 plays a major role in the mechanism of photooxidation mediated by these porphyrin derivatives. In addition an increase of the photosensitizing effect in the presence of zinc is observed. For each sensitizer, the ratio between type II and type I photoproducts has been calculated and compared to that of other known dyes such as methylene blue and riboflavin.     

cDNA sequence and genomic structure of the murine p55 (Mpp1) gene

Amplification and overexpression of the C-ERBB2 oncogene have been associated with a poor prognosis and a lower response to chemotherapy in human breast cancer. In this study, plasma c-erbB2 concentrations were determined using an enzyme immunoassay in patients with breast cancer. The links between c-erbB2 concentration and tumoral response to chemotherapy were established. The patients with a c-erbB2 concentration higher than the cut-off value (27 U/ml) were considered as c-erbB2+. Ten of the 33 metastatic breast cancers were c-erbB2+. No statistically significant difference in response to chemotherapy was noted between c-erbB2+ and c-erbB2- patients (4/10 objective responses versus 10/23). Variations in c-erbB2 concentrations during treatment were not related to response to treatment.     

The human FE65 gene: genomic structure and an intronic biallelic polymorphism associated with sporadic dementia of the Alzheimer type

This study aimed to investigate the relationship of systolic and diastolic blood pressure (BP) with a series of metabolic and nonmetabolic cardiovascular risk variables in a random sample of Turkish general adult population. Values of systolic and diastolic BP on the one hand and of six variables including body mass index (BMI), waist/hip ratio (W/H), grade of physical activity (PhA), plasma lipids and cigarette smoking from 1046 men and 1095 women aged 225 years were included in the analysis. Participants were classified into tertiles according to systolic and diastolic BP measurements, and were stratified in two age categories: 25-44 years (young) and 45-74 years (elderly). Plasma total cholesterol and triglyceride (Trg) concentrations were measured by the enzymatic method with the Reflotron apparatus. In multiple regression analysis, age proved the strongest independent determinant of BP. BMI was a strong independent marker of systolic and diastolic pressures in women, while in men the determinant value of the W/H was equivalent to BMI. For each increment of 1 kg/m2 of BMI was associated in men an increase of over 8 and 16 mmHg in diastolic and systolic pressure, respectively, regardless of age group. Corresponding figures in women were roughly 6 and 10 mmHg. Though plasma Trg were not independently associated with BP in either gender, the independent contribution of plasma cholesterol level in women to systolic and diastolic pressures was small but significant. BP was related to mean concentrations of plasma Trg in young adults only, total cholesterol levels were associated with diastolic pressure in young men only, whereas PhA grade was not associated with BP. These findings are consistent with the theory that, in the normal state, functions such as regulation of BP, body weight and lipid metabolism are closely linked to each other.     

Identification, genomic organization, and alternative splicing of KNSL3, a novel human gene encoding a kinesin-like protein

Despite increasing importance of molecular genetics, electromyography has preserved its place as a valuable tool in the diagnostic procedure of myopathies. Conventional electromyography allows the assessment of spontaneous activity, motor unit action potentials and interference patterns. In myopathies, fibrillations and positive sharp waves can be found in the majority of the cases. Motor unit action potentials are of short duration, low amplitude and may show increased polyphasia and number of satellite potentials. The interference pattern may be of low amplitude and compact already at submaximal contraction. Compared to conventional electromyography, automatic interference pattern analysis provides quantitative results and has the higher sensitivity and specificity. Normal conventional or automatic electromyography does not exclude a myopathy. For diagnostic purposes, electromyography will be followed by muscle biopsy and DNA analysis in most of the cases.     

Complete cDNA sequence, genomic structure, and chromosomal localization of the LPA receptor gene, lpA1/vzg-1/Gpcr26

The lpA1/Gpcr26 locus encodes the first cloned and identified G-protein-coupled receptor that specifically interacts with lysophosphatidic acid. A murine full-length cDNA of size consistent with that seen on Northern blots (3.7 kb) was determined using 3' rapid amplification of cDNA ends. Analysis of genomic clones revealed that the gene is divided into five exons, with one intron inserted in the coding region for transmembrane domain VI and one exon encoding the divergent 5' sequence in another published cDNA clone variant (orphan receptor mrec1.3). This structure differs from the intronless coding region for a homologous receptor, Edg1, but is identical to another more similar orphan receptor (lpA2) that has been deposited with GenBank. Using backcross analysis, both exons 1 and 4 mapped to a proximal region of murine Chromosome 4 indistinguishable from the vacillans gene. Exon 4 also mapped to a second locus on proximal Chromosome 6 in Mus spretus, and this partial duplication was confirmed by Southern blot. The genomic structure indicates a distinct, divergent evolutionary lineage for the vzg-1/lpA1 subfamily of receptors compared to those of homologous orphan receptor genes.     

Analysis of the structure and folding of the 3' genomic RNA of flaviviruses

The structure of the 3' genomic RNA of flaviviruses has been analyzed by thermal melting, and by chemical and enzymatic probing of model RNAs. The 3' RNA had more transitions than could be assigned to individual stem-loops and a transition in the 40-45 degrees C range was assigned to tertiary structure unfolding. In support of this assignment, mutants designed to destabilize the proposed pseudoknot tertiary structure lose the 40-45 degrees C transition. Enzyme cleavage of the RNA and chemical probing as a function of temperature also support a pseudoknot tertiary structure for the 3' flavivirus RNA.     

Characterization of gene expression, genomic structure, and chromosomal localization of Hells (Lsh)

We studied the development of multibank rod retinae by monitoring the size-related addition of new layers of rod inner and outer segments in four species of deep-sea fishes and found two different growth paradigms. In the mesopelagic Chauliodus sloani, new banks of rod inner and outer segments are added as long as the fish increases in size, as observed earlier by Locket (1980). By contrast, in three bathybenthic species (Antimora rostrata, Corvphaenoides (Coryphaenoides) guentheri, and Coryphaenoides (Nematonurus) armatus), the final complement of banks is reached when the specimens have grown to between 20 and 47% of their maximal size, suggesting that the visual system is mature only after this stage. Increase in retinal area, density of rod nuclei, and densities of rod inner and outer segments were also studied in these and additional species. Taken together with previous data on rod proliferation patterns and outer segment membrane synthesis, our findings indicate that at least in species with no continual addition of new banks, there is no major functional difference between the innermost and outermost banks of rod inner and outer segments. While Chauliodus spends all its life in the mesopelagic environment, the three bathybenthic species live in this environment during early development and descend towards greater depths only upon maturation. We speculate that this coincides with the stage when the full complement of rod banks is formed in the retina, as a possible prerequisite for a life outside the reach of sunlight.     

The genomic structure of DCTN1, a candidate gene for limb-girdle muscular dystrophy (LGMD2B)

Dynactin is a required activator for the molecular motor cytoplasmic dynein, and is likely to be essential for normal neuronal development. Previously we mapped the human gene encoding the p150Glued subunit of dynactin to 2p13, in the vicinity of the locus linked to limb-girdle muscular dystrophy (LGMB2B). We now report the genomic organization of DCTN1. We have identified 32 exons in the gene which spans approximately 25 kb. Alternative splicing of several of the exons generates functionally distinct isoforms of the p150Glued polypeptide.     

Long RT-PCR Amplification of the entire coding sequence of the polycystic kidney disease 1 (PKD1) gene

The peptidoglycan cortex of endospores of Bacillus species is required for maintenance of spore dehydration and dormancy, and the structure of the cortex may also allow it to function in attainment of spore core dehydration. A significant difference between spore and growing cell peptidoglycan structure is the low degree of peptide cross-linking in cortical peptidoglycan; regulation of the degree of this cross-linking is exerted by D,D-carboxypeptidases. We report here the construction of mutant B. subtilis strains lacking all combinations of two and three of the four apparent D, D-carboxypeptidases encoded within the genome and the analysis of spore phenotypic properties and peptidoglycan structure for these strains. The data indicate that while the dacA and dacC products have no significant role in spore peptidoglycan formation, the dacB and dacF products both function in regulating the degree of cross-linking of spore peptidoglycan. The spore peptidoglycan of a dacB dacF double mutant was very highly cross-linked, and this structural modification resulted in a failure to achieve normal spore core dehydration and a decrease in spore heat resistance. A model for the specific roles of DacB and DacF in spore peptidoglycan synthesis is proposed.     

A large deletion within the protein 4.1 gene associated with a stable truncated mRNA and an unaltered tissue-specific alternative splicing

Protein 4.1 is a major protein of the red blood cell skeleton. It binds to the membrane through its 30-kD N-terminal domain and to the spectrin-actin lattice through its 10-kD domain. We describe here the molecular basis of a heterozygous hereditary elliptocytosis (HE) associated with protein 4.1 partial deficiency. The responsible allele displayed a greater than 70-kb genomic deletion, beginning within intron 1 and ending within a 1.3-kb region upstream from exon 13. This deletion encompassed both erythroid and nonerythroid translation initiation sites. It accounts for the largest deletion known in genes encoding proteins of the red blood cell membrane. The corresponding mRNA was shortened by 1727 bases, due to the absence of exons 2 to 12. Nevertheless, this mRNA was stable. It showed a similar pattern in lymphoblastoid cells as in reticulocytes. Differential splicing of exons within the undeleted region remained regulated in a tissue-specific manner. Exons 14, 15, and 17a were absent from both reticulocyte and lymphocyte mRNAs, whereas exon 16 was present in reticulocytes but absent from lymphocytes. Thus, differential splicing on a local scale was not dependent on the overall structure of protein 4.1 mRNA in this particular instance.     

Analysis of the butyrylcholinesterase gene and nearby chromosome 3 markers in Alzheimer disease

The K-variant of butyrylcholinesterase (BCHE-K) recently has been reported to be associated with Alzheimer disease (AD) in carriers of the epsilon4 allele of the apolipoprotein E (APOE) gene. We have re-examined the frequency of the BCHE-K allele in a large data set of both sporadic and familial cases of AD disease, and we have also examined the segregation of three genetic markers on chromosome 3 near BCHE . Our data neither support an association of BCHE-K with sporadic or familial AD, nor do they suggest the existence of another gene nearby on chromosome 3 as a common cause of familial AD.     

Nuclear proteins from liver and kidney bind a 37 bp sequence in the 5' upstream region of the mGAT1 gene

The mouse GABA transporter (mGAT1) gene has been shown to be exclusively expressed in brain by Northern and Western blot analyses. The interactions between the 5' flanking region of the mGAT1 gene and nuclear proteins from different mouse tissues were studied by means of gel-shift assay. Our results show that nuclear protein factors from non-nervous tissues can specifically recognize a 37 bp sequence that is conserved in the 5' flanking region between the human and mouse GAT1 genes. Similar nuclear protein factors were also found to exist in rat, rabbit and pig.