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971.
Kanouchi H Oka T Asagi K Tachibana H Yamada K 《Cellular and molecular life sciences : CMLS》2000,57(7):1103-1108
To clarify the biological role of kidney perchloric acid-soluble protein 1 (K-PSP1), its expression and intracellular distribution were examined in normal rat kidney epithelial NRK-52E cells. K-PSP1 expression was low during the proliferating phase and high in the stationary phase, and shown to have a negative relationship with the protein-synthesizing activity of the cells. Immunocytochemical studies revealed that K-PSP1 is predominantly located in the cytosol, especially in endoplasmic reticulum and Golgi apparatus of proliferating cells. In the stationary phase, K-PSP1 was not detected immunologically even though protein and mRNA expression were high. This disappearance of reactivity with anti-serum seems to be due to a conformational change in K-PSP1 induced by unknown factors. These results suggest that the role of K-PSP1 is to regulate cell proliferation, and this may be related to a previously reported ability to inhibit protein synthesis. 相似文献
972.
Oxidative stress and hypoxia-like injury cause Alzheimer-type molecular abnormalities in central nervous system neurons 总被引:11,自引:0,他引:11
de la Monte SM Neely TR Cannon J Wands JR 《Cellular and molecular life sciences : CMLS》2000,57(10):1471-1481
Neuronal loss and neuritic/cytoskeletal lesions (synaptic disconnection and proliferation of dystrophic neurites) represent
major dementia-associated abnormalities in Alzheimer’s disease (AD). This study examined the role of oxidative stress as a
factor contributing to both the cell death and neuritic degeneration cascades in AD. Primary neuron cultures were treated
with H2O2 (9–90 μM) or desferrioxamine (2–25 μM) for 24 h and then analyzed for viability, mitochondrial mass, mitochondrial function,
and pro-apoptosis and sprouting gene expression. H2O2 treatment causes free-radical injury and desferrioxamine causes hypoxia-type injury without free radical generation. The
H2O2-treated cells exhibited sustained viability but neurite retraction, impaired mitochondrial function, increased levels of
the pro-apoptosis gene product CD95/Fas, reduced expression of N2J1-immunoreactive neuronal thread protein and synaptophysin,
and reduced distribution of mitochondria in neuritic processes. Desferrioxamine treatment resulted in dose-dependent neuronal
loss associated with impaired mitochondrial function, proliferation of neurites, and reduced expression of GAP-43, which has
a role in path-finding during neurite outgrowth. The results suggest that oxidative stress can cause neurodegeneration associated
with enhanced susceptibility to apoptosis due to activation of pro-apoptosis genes, neurite retraction (synaptic disconnection),
and impaired transport of mitochondria to cell processes where they are likely required for synaptic function. In contrast,
hypoxia-type injury causes neuronal loss with proliferation of neurites (sprouting), impaired mitochondrial function, and
reduced expression of molecules required to form and maintain synaptic connections. Since similar abnormalities occur in AD,
both oxidative stress and hypoxic injury can contribute to AD neurodegeneration.
Received 24 May 2000; received after revision 7 July 2000; accepted 27 July 2000 相似文献
973.
Calvete JJ Costa FH Saker-Sampaio S Murciano MP Nagano CS Cavada BS Grangeiro TB Ramos MV Bloch C Silveira SB Freitas BT Sampaio AH 《Cellular and molecular life sciences : CMLS》2000,57(2):343-350
The primary structure of a lectin isolated from the red alga Bryothamnion triquetrum was established by combination of Edman degradation of sets of overlapping peptides and mass spectrometry. It contains 91 amino acids and two disulphide bonds. The primary structure of the B. triquetrum lectin does not show amino acid sequence similarity with known plant and animal lectin structures. Hence, this protein may be the paradigm of a novel lectin family. 相似文献
974.
Differential basal synthesis of Hsp70/Hsc70 contributes to interindividual variation in Hsp70/Hsc70 inducibility 总被引:7,自引:0,他引:7
Boshoff T Lombard F Eiselen R Bornman JJ Bachelet M Polla BS Bornman L 《Cellular and molecular life sciences : CMLS》2000,57(8-9):1317-1325
The source of intraspecies variation in the expression of heat shock proteins (HSPs) remains unresolved but could shed light
on differential stress tolerance and disease susceptibility. This study investigated the influence of variable basal HSP synthesis
on differential inducibility of HSP synthesis. Basal and heat-induced synthesis of the major HSP families in peripheral blood
monocytes from healthy donors (n=42) were analysed using biometabolic labelling and densitometry. Basal Hsp70/Hsc70 synthesis
and percentage induction of Hsp70/Hsc70 synthesis were significantly correlated (r=−0.57, p<0.0001), and described most accurately
by an exponential decay equation (R=0.68, R2=0.46). This regression equation suggests that increasing levels of basal Hsp70/Hsc70 synthesis are accompanied byan exponential
decrease in the percentage induction of Hsp70/Hsc70 synthesis. The model fits data from European and non-European population
groups independently, although both coefficients in the regression equation were larger for non-Europeans. This implies population
group as an additional factor influencing differential HSP expression. The differential inducibility of Hsp70/Hsc70 due to
variable basal synthesis of Hsp70/Hsc70 and based upon population group may contribute to differential stress tolerance or
disease susceptibility.
Received 27 March 2000; received after revision 19 June 2000; accepted 20 June 2000 相似文献
975.
Roest Crollius H Jaillon O Bernot A Dasilva C Bouneau L Fischer C Fizames C Wincker P Brottier P Quétier F Saurin W Weissenbach J 《Nature genetics》2000,25(2):235-238
The number of genes in the human genome is unknown, with estimates ranging from 50,000 to 90,000 (refs 1, 2), and to more than 140,000 according to unpublished sources. We have developed 'Exofish', a procedure based on homology searches, to identify human genes quickly and reliably. This method relies on the sequence of another vertebrate, the pufferfish Tetraodon nigroviridis, to detect conserved sequences with a very low background. Similar to Fugu rubripes, a marine pufferfish proposed by Brenner et al. as a model for genomic studies, T. nigroviridis is a more practical alternative with a genome also eight times more compact than that of human. Many comparisons have been made between F. rubripes and human DNA that demonstrate the potential of comparative genomics using the pufferfish genome. Application of Exofish to the December version of the working draft sequence of the human genome and to Unigene showed that the human genome contains 28,000-34,000 genes, and that Unigene contains less than 40% of the protein-coding fraction of the human genome. 相似文献
976.
The activins (dimers of betaA or betaB subunits, encoded by the genes Inhba and Inhbb, respectively) are TGF-beta superfamily members that have roles in reproduction and development. Whereas mice homozygous for the Inhba-null allele demonstrate disruption of whisker, palate and tooth development, leading to neonatal lethality, homozygous Inhbb-null mice are viable, fertile and have eye defects. To determine if these phenotypes were due to spatiotemporal expression differences of the ligands or disruption of specific ligand-receptor interactions, we replaced the region of Inhba encoding the mature protein with Inhbb, creating the allele Inhbatm2Zuk (hereafter designated InhbaBK). Although the craniofacial phenotypes of the Inhba-null mutation were rescued by the InhbaBK allele, somatic, testicular, genital and hair growth were grossly affected and influenced by the dosage and bioactivity of the allele. Thus, functional compensation within the TGF-beta superfamily can occur if the replacement gene is expressed appropriately. The novel phenotypes in these mice further illustrate the usefulness of insertion strategies for defining protein function. 相似文献
977.
978.
979.
Maleck K Levine A Eulgem T Morgan A Schmid J Lawton KA Dangl JL Dietrich RA 《Nature genetics》2000,26(4):403-410