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1.
Structure,biosynthesis and functions of glycoprotein glycans 总被引:14,自引:0,他引:14
Eric G. Berger Eckhart Buddecke Johannis P. Kamerling Akira Kobata James C. Paulson Johannes F. G. Vliegenthart 《Cellular and molecular life sciences : CMLS》1982,38(10):1129-1162
Since the pioneering work on structure and function of heteroglycans compiled in the classical books edited by A. Gottschalk in 19721, there have been several promising developments in glycoconjugate research, as reviewed in this article.In Part 1, contributed by A. Kobata, current knowledge on heteroglycan structures is presented and representative examples taken from higher organisms are given. Part 2, written by J. F. G. Vliegenthart and J. P. Kamerling, covers the most important achievements in methodology: procedures to obtain pure glycans and to analyze their structures. Part 3, contributed by J. Paulson, is devoted to biosynthesis of glycans now describable as pathways since several of the glycosyltransferases have been isolated and analyzed for specificity. In Part 4, contributed by E. Buddecke, current knowledge on functional roles of glycans is presented. It will become apparent that the prerequisite for valid work either in biosynthetic or functional context depends on solid structural information. This is particularly true whenever glycosyltransferase reaction products are being analyzed, or glycans involved in biological functions are investigated. Although in past years, a great deal of important knowledge has been gathered by use of crude glycosidase or glycosyltransferase activities (a notable example is found in reference 2), one may now postulate that glycans implicated in biological reactions should be thoroughly analyzed.This review may familiarize newcomers with the field of glycoconjugate research with special emphasis on glycoprotein glycans. Glycolipids are not included in this article as they have recently been reviewed by S. I. Hakomori3. The reader is also referred to several excellent monographs4,5 and the Proceedings of the Glycoconjugate Symposia held biannually6–8. 相似文献
2.
Decisions on ass et allocations are often determined by covariance estimates from historical market data. In this paper, we introduce a wavelet-based portfolio algorithm, distinguishing between newly embedded news and long-run information that has already been fully absorbed by the market. Exploiting the wavelet decomposition into short- and long-run covariance regimes, we introduce an approach to focus on particular covariance components. Using generated data, we demonstrate that short-run covariance regimes comprise the relevant information for periodical portfolio management. In an empirical application to US stocks and other international markets for weekly, monthly, quarterly, and yearly holding periods (and rebalancing), we present evidence that the application of wavelet-based covariance estimates from short-run information outperforms portfolio allocations that are based on covariance estimates from historical data. 相似文献
3.
4.
Sanai N Nguyen T Ihrie RA Mirzadeh Z Tsai HH Wong M Gupta N Berger MS Huang E Garcia-Verdugo JM Rowitch DH Alvarez-Buylla A 《Nature》2011,478(7369):382-386
The subventricular zone of many adult non-human mammals generates large numbers of new neurons destined for the olfactory bulb. Along the walls of the lateral ventricles, immature neuronal progeny migrate in tangentially oriented chains that coalesce into a rostral migratory stream (RMS) connecting the subventricular zone to the olfactory bulb. The adult human subventricular zone, in contrast, contains a hypocellular gap layer separating the ependymal lining from a periventricular ribbon of astrocytes. Some of these subventricular zone astrocytes can function as neural stem cells in vitro, but their function in vivo remains controversial. An initial report found few subventricular zone proliferating cells and rare migrating immature neurons in the RMS of adult humans. In contrast, a subsequent study indicated robust proliferation and migration in the human subventricular zone and RMS. Here we find that the infant human subventricular zone and RMS contain an extensive corridor of migrating immature neurons before 18 months of age but, contrary to previous reports, this germinal activity subsides in older children and is nearly extinct by adulthood. Surprisingly, during this limited window of neurogenesis, not all new neurons in the human subventricular zone are destined for the olfactory bulb--we describe a major migratory pathway that targets the prefrontal cortex in humans. Together, these findings reveal robust streams of tangentially migrating immature neurons in human early postnatal subventricular zone and cortex. These pathways represent potential targets of neurological injuries affecting neonates. 相似文献
5.
Anderson BH Kasher PR Mayer J Szynkiewicz M Jenkinson EM Bhaskar SS Urquhart JE Daly SB Dickerson JE O'Sullivan J Leibundgut EO Muter J Abdel-Salem GM Babul-Hirji R Baxter P Berger A Bonafé L Brunstom-Hernandez JE Buckard JA Chitayat D Chong WK Cordelli DM Ferreira P Fluss J Forrest EH Franzoni E Garone C Hammans SR Houge G Hughes I Jacquemont S Jeannet PY Jefferson RJ Kumar R Kutschke G Lundberg S Lourenço CM Mehta R Naidu S Nischal KK Nunes L Ounap K Philippart M Prabhakar P Risen SR 《Nature genetics》2012,44(3):338-342
Coats plus is a highly pleiotropic disorder particularly affecting the eye, brain, bone and gastrointestinal tract. Here, we show that Coats plus results from mutations in CTC1, encoding conserved telomere maintenance component 1, a member of the mammalian homolog of the yeast heterotrimeric CST telomeric capping complex. Consistent with the observation of shortened telomeres in an Arabidopsis CTC1 mutant and the phenotypic overlap of Coats plus with the telomeric maintenance disorders comprising dyskeratosis congenita, we observed shortened telomeres in three individuals with Coats plus and an increase in spontaneous γH2AX-positive cells in cell lines derived from two affected individuals. CTC1 is also a subunit of the α-accessory factor (AAF) complex, stimulating the activity of DNA polymerase-α primase, the only enzyme known to initiate DNA replication in eukaryotic cells. Thus, CTC1 may have a function in DNA metabolism that is necessary for but not specific to telomeric integrity. 相似文献
6.
Peter J. Perkins Frederick G. Lindzey Jay A. Roberson Gregory McDaniel Randy Berger 《西北部美国博物学家》2011,49(2)
Winter habitat use and food habits of Blue Grouse ( Dendragapus obscurus ) were studied in an isolated Utah desert mountain range that contained little typical Douglas-fir ( Pseudotsuga menziesii ) winter habitat. Habitat use was concentrated in the Douglas-fir and pinyon ( Pinus edulis )-juniper ( Juniperus spp. ) habitat. Douglas-fir and pinyon pine were the most consumed foods. Other foods that represented >15% of the composition of an individual fecal sample were limber pine ( Pinus flexilis ), mahogany ( Cercocarpus ledifoliu ), juniper, and an Anteunaria-Cirsium type. The breadth in winter diet indicates that Blue Grouse may successfully occupy other habitats when typical winter habitat is scarce. 相似文献
7.
Berger W Steiner E Grusch M Elbling L Micksche M 《Cellular and molecular life sciences : CMLS》2009,66(1):43-61
The unique and evolutionary highly conserved major vault protein (MVP) is the main component of ubiquitous, large cellular
ribonucleoparticles termed vaults. The 100 kDa MVP represents more than 70% of the vault mass which contains two additional
proteins, the vault poly (ADP-ribose) polymerase (vPARP) and the telomerase-associated protein 1 (TEP1), as well as several
short untranslated RNAs (vRNA). Vaults are almost ubiquitously expressed and, besides chemotherapy resistance, have been implicated
in the regulation of several cellular processes including transport mechanisms, signal transmissions and immune responses.
Despite a growing amount of data from diverse species and systems, the definition of precise vault functions is still highly
complex and challenging. Here we review the current knowledge on MVP and vaults with focus on regulatory functions in intracellular
signal transduction and immune defence.
Received 27 June 2008; received after revision 25 July 2008; accepted 30 July 2008 相似文献
8.
Two major functions of the Golgi apparatus (GA) are formation of complex glycans and sorting of proteins destined for various
subcellular compartments or secretion. To fulfill these tasks proper localization of the accessory proteins within the different
sub-compartments of the GA is crucial. Here we investigate structural determinants mediating transition of the two glycosyltransferases
β-1,4- galactosyltransferase 1 (gal-T1) and the α-1,3-fucosyltransferase 6 (fuc-T6) from the trans-Golgi cisterna to the trans-Golgi network (TGN). Upon treatment with the ionophore monensin both glycosyltransferases are found in TGN-derived swollen
vesicles, as determined by confocal fluorescence microscopy and density gradient fractionation. Both enzymes carry a signal
consisting of the amino acids E5P6 in gal-T1 and D2P3 in fuc-T6 necessary for the transition of these glycosyltransferases from the trans-Golgi cisterna to the TGN, but not for their steady state localization in the trans-Golgi cisterna.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Received 30 July 2008; received after revision 17 September 2008; accepted 29 September 2008 相似文献
9.
Isolation of a candidate gene for Norrie disease by positional cloning. 总被引:17,自引:0,他引:17
W Berger A Meindl T J van de Pol F P Cremers H H Ropers C D?erner A Monaco A A Bergen R Lebo M Warburg 《Nature genetics》1992,1(3):199-203
The gene for Norrie disease, an X-linked disorder characterized by progressive atrophy of the eyes, mental disturbances and deafness, has been mapped to chromosome Xp11.4 close to DXS7 and the monoamine oxidase (MAO) genes. By subcloning a YAC with a 640 kilobases (kb) insert which spans the DXS7-MAOB interval we have generated a cosmid contig which extends 250 kb beyond the MAOB gene. With one of these cosmids, microdeletions were detected in several patients with Norrie disease. Screening of cDNA libraries has enabled us to isolate and sequence a likely candidate gene for Norrie disease which is expressed in retina, choroid and fetal brain. No homologous sequences were found in DNA and protein databases indicating that this cDNA is part of a gene encoding a 'pioneer' protein. 相似文献
10.