A single mutation in the 15S rRNA gene confers non sense suppressor activity and interacts with mRF1 the release factor in yeast mitochondria.

We have determined the nucleotide sequence of the mim3-1 mitochondrial ribosomal suppressor, acting on ochre mitochondrial mutations and one frameshift mutation in . The 15s rRNA suppressor gene contains a G633 to C transversion. Yeast mitochondrial G633 corresponds to G517 of the 15S rRNA, which is occupied by an invariant G in all known small rRNA sequences.

Wavefront propagation in turbulence: an unified approach to the derivation of angular correlation functions.

A general expression of the spatial correlation functions of quantities related to the phase fluctuations of a wave that have propagated through the atmospheric turbulence are derived. A generalization of the method to integrand containing the product of an arbitrary number of hypergeometric functions is presented. The formalism is able to give the coefficients of phase-expansion functions orthogonal over an arbitrary circularly symmetric weighting function for an isotropic turbulence spectrum, as well as to describe the effect of the finite outer and inner scales of the turbulence and to describe the spherical propagation or to derive the effects of the analytical operators acting on the phase such as the derivatives of any order.

[C7GC4]4 association into supra molecular i-motif structures.

The self-associative properties of cytidine-rich oligonucleotides into symmetrical i-motif tetramers give to these oligonucleotides the capacity of forming supramolecular structures (sms) that have potential applications in the nanotechnology domain. In order to facilitate sms formation, oligonucleotides containing two cytidine stretches of unequal length (C(n)XC(m)) separated by a non-cytidine spacer were synthesized. They were designed to associate into a tetramer including an i-motif core built by intercalation of the C.

The reverse transcriptase encoded by ai1 intron is active in trans in the retro-deletion of yeast mitochondrial introns.

Genomic mitochondrial intron deletion occurs frequently during the reversion of mitochondrial intronic mutations in Saccharomyces cerevisiae. The multiplicity as well as the apparent polarity of intron deletion led us to propose the implication of reverse transcription in this process. The two first introns of the COX1 (cytochrome oxidase I) gene, ai1 and ai2, are known to be homologous to viral reverse transcriptase and to encode such activity.

hnRNP A1 and the SR proteins ASF/SF2 and SC35 have antagonistic functions in splicing of beta-tropomyosin exon 6B.

Mutually exclusive splicing of exons 6A and 6B from the chicken beta-tropomyosin gene involves numerous regulatory sequences. Previously, we identified a G-rich intronic sequence (S3) downstream of exon 6B. This element consists of six G-rich motifs, mutations of which abolish splicing of exon 6B.

Effects of oligomycins on adenosine triphosphatase activity of mitochondria isolated from the yeasts Saccharomyces cerevisiae and Schwanniomyces castellii.

Functional mitochondria with respiratory control were isolated from the yeasts Saccharomyces cerevisiae and Schwanniomyces castellii. The presence of site I in Schw. castellii was indicated by higher ADP/O ratio than in S.

5'-End RET splicing: absence of variants in normal tissues and intron retention in pheochromocytomas.

The Ret tyrosine kinase is implicated in neuronal cell survival, kidney development and tumorigenesis. Several 3' and 5' transcript variants have been described resulting from alternative splicing of the RET pre-mRNA. The 3' variants code for three C-terminal isoforms, RET51, RET9 and RET43.

Natural resistance to inhibitors of the ubiquinol cytochrome c oxidoreductase of Rubrivivax gelatinosus: sequence and functional analysis of the cytochrome bc(1) complex.

Biochemical analyses of Rubrivivax gelatinosus membranes have revealed that the cytochrome bc(1) complex is highly resistant to classical inhibitors including myxothiazol, stigmatellin, and antimycin. This is the first report of a strain exhibiting resistance to inhibitors of both catalytic Q(0) and Q(i) sites. Because the resistance to cytochrome bc(1) inhibitors is primarily related to the cytochrome b primary structure, the petABC operon encoding the subunits of the cytochrome bc(1) complex of Rubrivivax gelatinosus was sequenced.

Aerobic and anaerobic NAD+ metabolism in Saccharomyces cerevisiae.

In Saccharomyces cerevisiae the nicotinic acid moiety of NAD+ can be synthesized from tryptophan using the kynurenine pathway or incorporated directly using nicotinate phosphoribosyl transferase (NPT1). We have identified the genes that encode the enzymes of the kynurenine pathway and for BNA5 (YLR231c) and BNA6 (YFR047c) confirmed that they encode kynureninase and quinolinate phosphoribosyl transferase respectively. We show that deletion of genes encoding kynurenine pathway enzymes are co-lethal with the Deltanpt1, demonstrating that no other pathway for the synthesis of nicotinic acid exists in S.

Spherical plant viruses: interactions in solution, phase diagrams and crystallization of brome mosaic virus.

Brome mosaic virus (BMV) is a small icosahedral plant virus of mean diameter 268 A. Interactions between BMV particles in solution were studied by means of small-angle X-ray scattering in order to find crystallization conditions. The interactions between biomacromolecules as large as these viruses have not yet been systematically studied by this method.

Ria1p (Ynl163c), a protein similar to elongation factors 2, is involved in the biogenesis of the 60S subunit of the ribosome in Saccharomyces cerevisiae.

RIA1 (YNL163c) is a quasi-essential gene that encodes a protein with strong similarities to elongation factors 2. Small C-terminal deletions in the protein lead to a severe growth defect. In the case of a 22-residue C-terminal deletion this can be suppressed by intragenic mutations in the RIA1 gene or dominant extragenic mutations in TIF6, which is thought to be involved in the biogenesis of the 60S subunit of the ribosome.

Mitochondrial translation of Saccharomyces cerevisiae COX2 mRNA is controlled by the nucleotide sequence specifying the pre-Cox2p leader peptide.

The mitochondrial gene encoding yeast cytochrome oxidase subunit II (Cox2p) specifies a precursor protein with a 15-amino-acid leader peptide. Deletion of the entire leader peptide coding region is known to block Cox2p accumulation posttranscriptionally. Here, we examined in vivo the role of the pre-Cox2p leader peptide and the mRNA sequence that encodes it in the expression of a mitochondrial reporter gene, ARG8m, fused to the 91st codon of COX2.

Physical structure of the excitable membrane of unmyelinated axons: X-ray scattering study and electrophysiological properties of pike olfactory nerve.

The aim of this work was to elicit correlations between physical structure and physiological functions in excitable membranes. Freshly dissected pike olfactory nerves were studied by synchrotron radiation X-ray scattering experiments and their physiological properties were tested by electrophysiological techniques. The scattering spectra contained a sharply oriented equatorial component (i.

Regulation of the CYB2 gene expression: transcriptional co-ordination by the Hap1p, Hap2/3/4/5p and Adr1p transcription factors.

Expression of the Saccharomyces cerevisiae nuclear gene CYB2 encoding the mitochondrial enzyme L-(+)-lactate-cytochrome c oxidoreductase (EC 1.2.2.

Cbk1p, a protein similar to the human myotonic dystrophy kinase, is essential for normal morphogenesis in Saccharomyces cerevisiae.

We have studied the CBK1 gene of Saccharomyces cerevisiae, which encodes a conserved protein kinase similar to the human myotonic dystrophy kinase. We have shown that the subcellular localization of the protein, Cbk1p, varies in a cell cycle-dependent manner. Three phenotypes are associated with the inactivation of the CBK1 gene: large aggregates of cells, round rather than ellipsoidal cells and a change from a bipolar to a random budding pattern.

Paramecium GPI proteins: variability of expression and localization.

In Paramecium primaurelia, the two major classes of cell surface proteins, the surface antigen (SAg) and the surface GPI proteins (SGPs), are linked to the plasma membrane through a glycosylphosphatidylinositol (GPI) anchor. In the present study, we have characterized the expression of the SGPs in several geographical strains of P. primaurelia and P.

Human microsomal epoxide hydrolase is the target of germander-induced autoantibodies on the surface of human hepatocytes.

Germander, a plant used in folk medicine, caused an epidemic of cytolytic hepatitis in France. In about half of these patients, a rechallenge caused early recurrence, suggesting an immunoallergic type of hepatitis. Teucrin A (TA) was found responsible for the hepatotoxicity via metabolic activation by CYP3A.

Relative expression of the RET9 and RET51 isoforms in human pheochromocytomas.

Activating mutations of the RET oncogene cause the inheritance of multiple endocrine neoplasia type 2 (MEN2). The RET pre-mRNA is spliced into several transcripts coding for multiple isoforms, including Ret9 and Ret51. When harboring activating mutations in the cytoplasmic region, the Ret51 protein displays a higher in vitro transforming efficiency as compared to the corresponding Ret9 isoform.

Line Intensities of (12)C(16)O(2) in the 1.2-1.4 µm Spectral Region.

The 7000-8500 cm(-1) spectral region of (12)C(16)O(2) has been investigated using the high-resolution FT spectrometer of LPPM in Orsay. The two strongest bands in this region are the 10031 <-- 00001 and 10032 <-- 00001 bands centered at 8294 and 8192 cm(-1). Line intensities in these two bands and in the 40013 <-- 00001 and 40014 <-- 00001 bands have been measured.

High levels of tyrosine phosphorylated proto-ret in sporadic phenochromocytomas.

Pheochromocytomas are tumors originating from chromaffin cells, the large majority of which are sporadic neoplasms. The genetic and molecular events determining their tumorigenesis continue to remain unknown. On the other hand, RET germ-line mutations cause the inheritance of familial tumors in multiple endocrine neoplasia (MEN)-2 diseases, which account for a minority of pheochromocytomas.

The respiratory gene OXA1 has two fission yeast orthologues which together encode a function essential for cellular viability.

The Saccharomyces cerevisiae nuclear gene OXA1, which is conserved from prokaryotes to human, was shown to be essential for cytochrome c oxidase and F1F0-ATP synthase biogenesis. We have searched for an orthologue of OXA1 in Schizosaccharomyces pombe, another yeast that is highly diverged from S. cerevisiae and which could more closely model higher eukaryotes.

A 'natural' mutation in Saccharomyces cerevisiae strains derived from S288c affects the complex regulatory gene HAP1 (CYP1).

The HAP1 gene encodes a complex transcriptional regulator of many genes involved in electron-transfer reactions and is essential in anaerobic or heme-depleted conditions. We show here that strains derived from S288c carry a defective Ty1 element inserted in the 3' region of the HAP1 ORF. This mutant allele acts as a HAP1 null allele in terms of cytochrome c expression and CYC1 UAS1-dependent transcription, but is able to sustain limited growth in heme-depleted conditions.

Anderson's disease: exclusion of apolipoprotein and intracellular lipid transport genes.

Anderson's disease is a rare, hereditary hypocholesterolemic syndrome characterized by chronic diarrhea, steatorrhea, and failure to thrive associated with the absence of apo B48-containing lipoproteins. To further define the molecular basis of the disease, we studied 8 affected subjects in 7 unrelated families of North African origin after treatment with a low-fat diet. Lipid loading of intestinal biopsies persisted, but the pattern and extent of loading was variable among the patients.