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SUN4 is the fourth member of the SUN gene family from S. cerevisiae, whose products display high homology in their 258 amino acid C-terminal domain. SIM1, UTH1, NCA3 (the founding members) are involved in different cellular proces...
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SUN4 is the fourth member of the SUN gene family from S. cerevisiae, whose products display high homology in their 258 amino acid C-terminal domain. SIM1, UTH1, NCA3 (the founding members) are involved in different cellular processes (DNA replication, ageing, mitochondrial biogenesis) and it is shown herein that SUN4 plays a role in the cell septation process, sun4 Delta cells are larger than wild-type and begin a new cell cycle before they have separated from their mother cell. This phenotype is more pronounced in sun4 Delta cells also deleted for UTH1. FAGS analysis shows apparent polyploidy which disappears when the cell cycle is arrested by mating factor or nocodazole, indicating that cell septation is delayed without modification of the doubling time. Elutriated sun4 Delta uth1 Delta daughter cells are born larger, and therefore enter S phase sooner than their wild-type counterpart. S phase duration, as well as timing of Clb2 degradation, is normal, but cell septation is delayed. Sun4p/Scw3p was recently described as a cell wall protein (Cappellaro et al., 1998) and, consistent with this notion, electron micrographs of sun4 Delta cells show defects in the final steps of cell wall septation. Our data suggest that Sun4p and Uth1p might contribute to the regulated process of cell wall morphogenesis and septation. Copyright (C) 2000 John Wiley & Sons, Ltd.
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This article evaluates rural development policies. Rural development policies are confronted with a diversification of the evolution trajectories of rural areas. They must moreover include new objectives like risk prevention and t...
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This article evaluates rural development policies. Rural development policies are confronted with a diversification of the evolution trajectories of rural areas. They must moreover include new objectives like risk prevention and the limitation of negative constraints on the resources. A thorough examination of the appraisal practices of rural development policy reveals judicious and disadvantageous approaches.
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The reinforcement of decentralization in France and regionalization in Europe lead to take into account and to analyze the interventions of local public authorities: departments and regions. The framework of local economic interve...
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The reinforcement of decentralization in France and regionalization in Europe lead to take into account and to analyze the interventions of local public authorities: departments and regions. The framework of local economic interventions opens new perspectives. Concerning agricultural supports, the amounts devoted to the development of agriculture appear weak but their interest rests in their orientation: animation of the networks of actors, support to territorial demonstrations or to local productions.
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Just like rural areas themselves, rural development policies have undergone a radical change over the last decades. This text presents the rural development concepts included in these policies, their processes, their intervention ...
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Just like rural areas themselves, rural development policies have undergone a radical change over the last decades. This text presents the rural development concepts included in these policies, their processes, their intervention instruments and the strategies that they can promote. It insists on the fact that this evolution is not linear. With the objective of reconciling fairness and efficiency, rural development policies continually oscillate between support for the evolution of the agricultural sector, aiming at a more global and integrated development of a homogeneous rural territory, creating a synergy between rural territories and urban dynamics at the regional scale.
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Pt-Sn/Al2O3 catalysts were prepared using two different methods, namely, by ''traditional'' coimpregnation with H2PtCl6 and SnCl4 and by a ''new'' method in which the bimetallic complex precursor [Pt(NH3)(4)][SnCl6] is prepared on...
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Pt-Sn/Al2O3 catalysts were prepared using two different methods, namely, by ''traditional'' coimpregnation with H2PtCl6 and SnCl4 and by a ''new'' method in which the bimetallic complex precursor [Pt(NH3)(4)][SnCl6] is prepared on the support. Their catalytic activity and selectivity in n-hexane reactions were studied as a function of the hydrogen pressure (60-480 Torr) and compared with those of monometallic Pt/Al2O3 catalysts using H2PtCl6 or [Pt(NH3)(4)]Cl-2 as Pt precursors. Pt/Al2O3 ex [Pt(NH3)(4)]Cl-2 showed very low dispersion and exhibited high selectivity in reactions attributed to multiatomic ensembles. The results with bimetallic catalysts can be rationalized in terms of two phases being present, a PtSn alloy phase plus Pt in fine distribution. The ''new'' Pt-Sn/Al2O3 from the bimetallic precursor contains the two metals in a better dispersion, resulting ina larger number of atomically dispersed surface Pt active sites. This catalyst gave more isomers (and methylcyclopentane) and fewer fragments and less benzene than the ''traditional'' sample. The ''new'' Pt-Sn/Al2O3 sample possessed good long-term stability, The ''traditional'' sample lost some of its activity and its high hydrogenolysis selectivity during long use; i.e.,it approached the catalytic properties of the ''new'' sample. Both samples are potential candidates as catalysts with high isomerizing and low aromatic selectivities (up to 75% isohexanes plus methylcyclopentane as opposed to a maximum of 20% benzene). The results could be explained sufficiently with a geometric model, electronic interactions playing a less important role in the catalytic phenomena observed. (C) 1997 Academic Press. [References: 62]
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Large and unselective permeabilities through the inner membrane of yeast mitochondria have been observed for more than 20 years, but the characterization of these permeabilities, leading to hypothesize the existence of a large-con...
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Large and unselective permeabilities through the inner membrane of yeast mitochondria have been observed for more than 20 years, but the characterization of these permeabilities, leading to hypothesize the existence of a large-conductance unselective channel in yeast inner mitochondrial membrane, was done only recently by several groups. This channel has been tentatively identified as a yeast counterpart to the mammalian permeability transition pore, the crucial role of which is now well-documented in physiopathological phenomena, such as Ca2+ homeostasis, ischemic damages, or programmed cell death. The aim of this review is to make a point on the known characteristics of this yeast mitochondrial unselective channel (YMUC) and to analyze whether or not it can be considered as a "yeast permeability transition pore.". [References: 58]
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Cholesteryl ester transfer protein (CETP) is a key factor in plasma reverse cholesterol transport and is implicated in the pathophysiology of atherogenic dyslipidemia. Variations observed in plasma CETP mass and activity in both n...
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Cholesteryl ester transfer protein (CETP) is a key factor in plasma reverse cholesterol transport and is implicated in the pathophysiology of atherogenic dyslipidemia. Variations observed in plasma CETP mass and activity in both normolipidemic and dyslipidemic individuals may reflect differences in CETP gene expression. We evaluated the respective roles of the Sp1 and Spa transcription factors on the promoter activity of the human CETP gene at a new Sp1/Sp3 site identified at position -690, and at two previously described Sp1/Sp3 sites at positions -37 and -629. In transient transfection in HepG2 cells, site-directed mutagenesis using luciferase reporter constructs containing a promoter fragment from +32 to -745 indicated that the new -690 site acts as a repressive element in reducing CETP promoter activity (-22%; P < 0.05); equally, this site exerts an additive effect with the -629 site, inducing marked repression (-42%; P < 0.005). In contrast, in NCTC cells that display a 16-fold lower level of Spa, the repressive effect at the -690 site was enhanced 2-fold (-45%; P < 0.05), whereas the -629 site exerted no effect. Cotransfection of Sp1 and/or Sp3 in SL2 insect cells lacking endogenous Sp factors demonstrated that Sp1 and Spa act as activators at the -690 and -37 sites, whereas Spa acts as a repressor at the -629 site. Taken together, our data demonstrate that Sp1 and Spa regulate human CETP promoter activity through three Sp1/Sp3 binding sites in a distinct manner, and that the Sp1/Sp3 ratio is a key factor in determining the relative contribution of these sites to total promoter activity. [References: 63]
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The cholesteryl ester transfer protein (CETP) plays a key role in reverse cholesterol transport in mediating the transfer of cholesteryl ester from HDL to atherogenic apolipoprotein B-containing lipoproteins (VLDL, IDL, and LDL). ...
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The cholesteryl ester transfer protein (CETP) plays a key role in reverse cholesterol transport in mediating the transfer of cholesteryl ester from HDL to atherogenic apolipoprotein B-containing lipoproteins (VLDL, IDL, and LDL). Variation in plasma CETP mass in both normolipidemic and dyslipidemic individuals may reflect differences in CETP gene expression. As the 5' flanking sequence up to 3.4 kb of the human CETP gene contributes to transcriptional activity and tissue-specific gene expression, we evaluated the role of the distal promoter region in the modulation of CETP gene expression. In transfection experiments in HepG2 cells, we presently demonstrate that an Alu repeat (72,153/-2,414) acts as a repressive element, whereas a binding site for the orphan nuclear receptor CYP7A promoter binding factor (CPF), at position -1,042, facilitates activation of human CETP promoter activity. Cotransfection of liver receptor homolog, the mouse homologue of CPF in HEK293 cells that lack CPF, indicated that the -1,042 CPF site is sufficient to induce CPF-mediated activation of CETP promoter activity. Taken together, our results indicate that the distal-promoter region is a major component in the modulation of human CETP promoter activity, and that it may contribute to the liver-specific expression of the CETP gene. [References: 38]
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