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E Fabre

Publications and source records attributed to E Fabre.

36 records · Page 2Linked to original sources
PubMed1996

Yeast nucleoporin mutants are defective in pre-tRNA splicing.

We have screened nucleoporin mutants for the inhibition of tRNA splicing, which has previously been proposed to be coupled to transport. Strains mutant for Nup49p or Nup116p, or genetically depleted of Nup145p, strongly accumulated unspliced pre-tRNAs. Splicing was inhibited for all 10 families of intron-containing pre-tRNA, but no effects on 5' or 3' end processing were detected. Strains mutant for Nup133p or Nsp1p accumulated lower levels of several unspliced pre-tRNAs. In contrast, no accumulation of any pre-tRNA was observed in strains mutant for Nup1p, Nup85p, or Nup100p. Other RNA processing reactions tested, pre-rRNA processing, pre-mRNA splicing, and small nucleolar and small nuclear RNA synthesis, were not clearly affected for any nucleoporin mutant. These data provide evidence for a coupling between pre-tRNA splicing and nuclear-cytoplasmic transport. Mutation of NUP49, NUP116, or NUP145 has previously been shown to lead to nuclear poly(A)+ RNA accumulation, indicating that these nucleoporins play roles in the transport of more than one class of RNA.

Base Sequence↗
PubMed1996

Perinatal mortality in term and post-term births.

Our aim was to compare the fetal mortality rate (FMR), early neonatal mortality rate (ENMR) and perinatal mortality rate (PMR) of post-term and term births, 2) to examine trends in the incidence and perinatal mortality rates of post-term and term births. We used data from Spanish Perinatal Mortality Survey of 1980, 1986, 1989 and 1992. The data include 40,863 post-term births (42 weeks and over) and 517,060 term births (37-41 weeks). Perinatal mortality rates of post-term and term births were compared. The incidence of post-term births was 7.3%. The relative risk (RR) of FMR for post-term compared to term births was 1.1 (95% confidence interval [CI] 0.9-1.3), of ENMR was 1.6 (95% CI 1.4-2.0) and of PMR was 1.3 (95% CI 1.1-1.5). From 1980 to 1992 there was a significant reduction in the incidence of post-term births (8.1% vs 5.0%), in the FMR (4.5/1000 vs 1.9/1000), ENMR (4.3/1000 vs 2.0/1000) and PMR (8.7/1000 vs 3.9/1000) of post-term births. There was no significant difference in the FMR between post-term and term in each year studied. Post-term births had a significantly higher ENMR and PMR than term births in 1980, and they were equivalent from 1983 to 1992. The incidence of post-term births, its FMR, ENMR and PMR have been significantly reduced during the whole period studied.

Female↗
PubMed1994

Nup145p is required for nuclear export of mRNA and binds homopolymeric RNA in vitro via a novel conserved motif.

An essential yeast protein, Nup145p, is identified via its genetic interaction with the nucleoporin Nsp1p. Nup145p contains GLFG repeats and localizes to nuclear pores. Depletion of Nup145p in vivo leads rapidly to nuclear retention of polyadenylated RNAs and more slowly to cytoplasmic accumulation of a nuclear reporter protein. A stretch of 140 amino acids within Nup145p is conserved in two other yeast nucleoporins, Nup116p and Nup100p, and in an uncharacterized C. elegans protein. Genetic experiments in yeast reveal that the three copies of the motif carry out an essential, redundant function. Fragments of Nup145p and Nup116p including this motif bind specifically to homopolymeric RNAs in vitro. Nup145p, Nup116p, and Nup100p thus represent a novel class of nucleoporins involved in nucleocytoplasmic transport.

Amino Acid Sequence↗
PubMed1994

Nuclear transport.

A striking property of nuclear pore complexes is their ability to mediate bi-directional nucleocytoplasmic traffic of proteins and RNAs. In the past year, several new nuclear pore proteins have been identified, but their precise functions remain to be established. Cytosolic factors responsible for the recognition and docking of substrates for nuclear transport are also being characterized. It appears that different factors are required for the import of karyophilic proteins versus small nuclear ribonucleoprotein particles. Furthermore, the GTPase Ran/TC4 has been shown to play a key role in translocation across the nuclear pore complex. Specific RNAs require different sets of factors for their export from the nucleus, although a common export route appears to be utilized by different RNA species. In contrast, nuclear retention has been found to have an influence in controlling the rate of protein exit from the nucleus.

Animals↗
PubMed1993

Analysis of nucleo-cytoplasmic transport in a thermosensitive mutant of nuclear pore protein NSP1.

NSP1 is related to a group of nuclear pore proteins termed 'nucleoporins'. We observe that in thermosensitive nsp1 mutants lacZ fusion proteins which contain the nuclear targeting sequence of Mat alpha 2 or Pho2 are located inside the nucleus at the permissive temperature (23 degrees C), but are mislocalized in the cytoplasm at the restrictive temperature (37 degrees C). No evidence was obtained that the large lacZ reporter protein leaks out from the nucleus. Another nuclear passenger protein consisting of the NLS of ribosomal protein L25 and cytosolic dihydrofolate reductase (DHFR) is also accumulating in the cytoplasm after shifting ts nsp1 cells to 37 degrees C. In the latter case, this could be attributed to an increased leakage of the reporter protein from the nucleus into the cytoplasm. These data suggest that NSP1 mutation affects nuclear transport and nuclear retention, but the effects depend on the used NLS and the reporter protein.

Biological Transport↗
PubMed1992

Intracellular transit of a yeast protease is rescued by trans-complementation with its prodomain.

The alkaline extracellular protease (AEP) of the yeast Yarrowia lipolytica is synthesized as a preproprotein. The precursor undergoes a complex maturation during its intracellular transit, successively involving signal peptide cleavage, dipeptidyl aminopeptidase processing, and cleavage at a dibasic site which results in the extracellular release of the active enzyme. It was previously shown that various deletions within the proregion affect the intracellular transit of the protease. Prodeleted precursors are translocated and have their signal sequences removed, but they accumulate in the secretion apparatus. We show here that the secretion of partially active proteins is restored when the prodomain is supplied in trans as an independent peptide. The secretion rescue and maturation processing that are reconstituted by the free propeptide do not reach wild type efficiency. The results of pulse-chase experiments indicate that a rate-limiting step occurs during the intracellular transit of the rescued precursors, before Kex2p proteolytic cleavage. This delayed maturation seems to be responsible for an overall slower release of the rescued polypeptides. Propeptide and AEP were secreted in equimolar amounts by both wild type and trans-complemented strains, but none could be detected in the supernatant when expressed alone. These experiments suggest that the prodomain of AEP initially acts as a crucial folding aid for the early secretory transit of the translocated precursor. They further suggest that the prodomain is also required for a second structural change of the AEP precursor during its activation.

Amino Acid Sequence↗
PubMed1992

Effect of centrifugation on amniotic fluid phospholipid composition.

The first step in the determination of phospholipid in amniotic fluid is generally the removal of cells and debris from the fluid by centrifugation. Low-speed centrifugation of the supernatant is reported to have the same phospholipidic profile and L/S, PG/S and PI/S ratios similar to those of the uncentrifuged amniotic fluid sample. With high-speed centrifugation almost all the pulmonary surfactant seems to be recovered in pellet with the same characteristics as the uncentrifuged amniotic fluid.

Amniotic Fluid↗
PubMed1991

Role of the proregion in the production and secretion of the Yarrowia lipolytica alkaline extracellular protease.

The yeast Yarrowia lipolytica secretes an alkaline extracellular protease (AEP). It is first synthesized as a precursor comprising a putative signal peptide, a stretch of 10 X-Ala or X-Pro sequences that are substrates for a dipeptidyl aminopeptidase, a large pro-region that contains a glycosylation site and two Lys-Arg sites that can be cleaved by a KEX2-like endoprotease and finally the mature protease itself. A defect in the XPR6 (KEX2-like) gene results in the secretion of an inactive proenzyme (Matoba, S., and Ogrydziak, D. M. (1989) J. Biol. Chem. 264, 6037-6043), showing that the proregion inhibits protease activity. To determine whether the proregion plays an additional role in protease secretion, we have generated deletions and point mutations in the corresponding region of the structural gene. In this paper we examine the effects of these mutations on AEP secretion and maturation and show that the proregion is essential for its secretion. All deletions affecting the proregion resulted in the intracellular accumulation of unprocessed precursors. Deletion of the glycosylation site in the proregion resulted in the production of an unglycosylated precursor that was secreted and matured correctly at 18 degrees C but accumulated in the cells at 28 degrees C. From these results, we propose that the AEP prosequence plays an additional essential role in guiding the proper folding of the protein into a conformation compatible with secretion.

Amino Acid Sequence↗
PubMed1989

Expression of invertase activity in Yarrowia lipolytica and its use as a selective marker.

Few selective markers are available for the transformation of the industrial yeast Yarrowia lipolytica, and those that are require the use of specialized hosts (e.g., auxotrophs, antibiotic sensitive). To enable the transformation of any Y. lipolytica strain, we used the property that Y. lipolytica cannot use sucrose as a sole carbon source. We have constructed a gene fusion where the Saccharomyces cerevisiae SUC2 gene is placed under the control of the promoter and signal sequence of the Y. lipolytica XPR2 gene, which encodes an Alkaline Extracellular Protease (AEP). Strains bearing this fusion express invertase activity and grow on sucrose as a carbon source. The activity follows the same regulation as does the alkaline extracellular protease, is secreted into the periplasm and confers a Suc+ phenotype. It was shown that this chimeric gene could be used as a dominant marker for transformation in a one-step procedure.

Amino Acid Sequence↗
PubMed1988

Perinatal mortality in twin pregnancy: an analysis of birth weight-specific mortality rates and adjusted mortality rates for birth weight distributions.

The objective of this study is to compare the fetal mortality rate (FMR), early neonatal mortality rate (ENMR) and perinatal mortality rate (PMR) of twin and single births. It is based on a survey which was carried out in 22 Hospital Centers in Spain in 1980, and covered 1,956 twins born and 110,734 singletons born. The FMR in twins was 36.3/1000 and 8.8/1000 for singletons. The ENMR in twins was 36.1/1000 and 5.7/1000 for singletons. The PMR in twins was 71.1/1000 and 14.4/1000 for singletons. When birthweight-specific PMR in twin and singletons births are compared, there were no differences between the rates for groups 500-999 g and 1000-1499 g. For birthweight groups of 1500-1999 g (124.4 vs 283.8/1000) and 2000-2999 g (29.6 vs 73.2/1000) the rates for twins were about twice lower than those for single births. The PMR for 2500 g and over birthweight was about twice higher in twins than in singletons (12.5 vs 5.5/1000). After we adjusted for birthweight there was a difference in the FMR (12.6 vs 9.8/1000) and the PMR (19.1 vs 16.0/1000, and no difference in the ENMR between twins and singletons (5.9 vs 6.4/1000), indicating that most of the differences among crude rates are due to differences in distribution of birthweight.

Birth Weight↗
PubMed1988

[Intrauterine growth in gestational diabetes].

Infants of diabetic tend to have more adipose tissue than normal infants at birth. This is thought to be caused by maternal hyperglycemia and fetal hyperinsulinism. Authors examined 160 newborn infants of mothers with gestational diabetes, to determine whether there is a relation between maternal blood-glucose concentrations and subcutaneous fat in the newborn. Mothers of newborns "large for age" present a mean fasting blood-glucose in third trimester greater than mothers of newborns "adequate for age" (p 0.05). Babies born to mothers who had a mean fasting blood-glucose above 90 mg/100 ml had more subcutaneous fat tissue than newborn infants of mothers with a mean fasting blood-glucose under 90 mg/ml (p less than 0.01). Maternal fasting blood-glucose and mean blood-glucose in the third trimester correlated significantly with neonatal weight, skin-fold thickness, K index and body mass index.

Adipose Tissue↗
PubMed1986

A practical method to analyze the phospholipids in the amniotic fluid using HPTLC.

An operative method using HPTLC which makes possible the determination of nine phospholipids in the amniotic fluid individually is described: lysophosphatidylcholine, sphingomyelin, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid and cardiolipine. Since a simple and reliable method for clinical practice was sought, the working techniques, materials, chromatographic solvents and staining reagents were chosen accordingly. The standardization method was made by using standard phospholipids. This method was tested with 34 samples of amniotic fluid. A discussion of the practical application in the determination of some ratios of fetal pulmonary maturity is made.

Amniotic Fluid↗
PubMed1983

[Advances in neonatal intensive medicine].

In the last few year a significative reduction on the rates of neonatal morbimortality have appeared. This has been achieved because a better understanding of embrio-fetal physiology, emerged under the patronage of technological development: new diagnostic techniques, monitorization (physiological and therapeutical) in both, pre and postnatal periods. This model of attendance (perinatology) has its' climax in neonatal intensive care. New scientific plans have to be examined continuously in a critical way, according with ethical reasons related with this type of medical assistance.

Amniocentesis↗
PubMed1976

[Relations between the oxytocin test and morphometry of the placenta].

We have studied placental morphometry after delivery in 23 cases in which the oxytocin challenge test was carried out towards the end of the pregnancy. Thus we have been able to compare the results of the two and establish details of placental measurement that have the greatest influence on its function. The following parameters seem to have the most direct influence, by statistical relationship, with placental insufficiency: the total surface of the villi, the concentration of villi per unit sectioned, the surface of fetal capillaries and the mean diameter of these capillaries. On the other hand the mean diameter of the villi and the number of capillaries per villus do not seem to have any relationship to function. These results bring further proof to our old ideas as to the value of placental morphometry and confirm the value of the oxytocin challenge test.

Adult↗