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41.
Bent DNA at a yeast autonomously replicating sequence 总被引:52,自引:0,他引:52
42.
Molecular aspects of the imipramine 'receptor' 总被引:4,自引:0,他引:4
A Davis 《Experientia》1984,40(8):783-794
43.
The segregation of voltage-dependent sodium channels to specialized regions of the neuron is crucial for propagation of an action potential. Studies of their lateral mobility indicate that sodium channels are freely mobile on the neuronal cell body but are immobile at the axon hillock, presynaptic terminal and at focal points along the axon. To elucidate the mechanisms that regulate sodium channel topography and mobility, we searched for specific proteins from the brain that associate with sodium channels. Here we show that sodium channels labelled with 3H-saxitoxin (STX) are precipitated in the presence of exogenous brain ankyrin by anti-ankyrin antibodies and that 125I-labelled ankyrin binds with high affinity to sodium channels reconstituted into lipid vesicles. The cytoplasmic domain of the erythrocyte anion transporter competes for the latter interaction. Neither the neuronal GABA (gamma-aminobutyric acid) receptor channel complex nor the dihydropyridine (DHP) receptor bind brain ankyrin. The results indicate that brain ankyrin links the voltage-dependent sodium channel to the underlying cytoskeleton and may help to maintain axolemmal membrane heterogeneity and control sodium channel mobility. 相似文献
44.
Non-function of a Moloney murine leukaemia virus regulatory sequence in F9 embryonal carcinoma cells 总被引:3,自引:0,他引:3
Moloney murine leukaemia virus (M-MuLV) infection of embryonal carcinoma (EC) cells results in the integration of proviral DNA into the host cell genome, but not in virus production. One suggested explanation for the lack of viral gene expression in EC cells has been methylation of the integrated viral DNA. However, subsequent reports indicated that integration of the M-MuLV DNA occurs soon after infection, but that viral DNA methylation occurs considerably later. Nevertheless, viral gene expression is not observed even at early times. One possible explanation is that certain M-MuLV regulatory sequences do not function in EC cells. We now present evidence which supports this hypothesis. 相似文献
45.
Movement and segregation of kinetochores experimentally detached from mammalian chromosomes 总被引:16,自引:0,他引:16
B R Brinkley R P Zinkowski W L Mollon F M Davis M A Pisegna M Pershouse P N Rao 《Nature》1988,336(6196):251-254
The kinetochore is a specialized structure at the centromere of eukaryotic chromosomes that attaches chromosomes to the mitotic spindle. Recently, several lines of evidence have suggested that kinetochores may have more than a passive role in the movement of chromosomes during mitosis and meiosis. Kinetochores seem to attract and 'capture' microtubules that grow from the spindle poles and microtubules may lengthen or shorten by the addition or subtraction of tubulin subunits at their kinetochore-associated ends. An attractive hypothesis is that kinetochores function as 'self-contained engines running on a microtubule track'. Here, we show that kinetochores can be experimentally detached from chromosomes when caffeine is applied to Chinese hamster ovary cells that are arrested in the G1/S phase of the cell cycle. The detached kinetochore fragments can still interact with spindle microtubules and complete all the mitotic movements in the absence of other chromosomal components. As these cells enter mitosis before DNA synthesis is completed, chromosome replication need not be a prerequisite for the pairing, alignment and segregation of kinetochores. 相似文献
46.
47.
Analysis of three new T-cell receptor beta-chain variable regions together with those in the literature indicates that they have both remarkable similarities and differences with those of immunoglobulin. Less than 10 V regions appear to predominate in the thymus. V beta sequences are much more heterogeneous at the amino acid level than are immunoglobulin V regions and they appear to diverge between species much more quickly, apparently the result of additional hypervariable regions. Three of these putative new hypervariable regions lie outside of the classical immunoglobulin binding site, an indication that important interactions may be occurring in these regions with polymorphic MHC determinants. 相似文献
48.
N. E. Erlick E. D. Engel R. H. Davis 《Cellular and molecular life sciences : CMLS》1981,37(5):481-482
Summary Adult male mice maintained on a zinc-free diet display a statistically significant increase in open field locomotion compared to controls. However, excess zinc (100 times the established recommended daily allowance) does not produce a change compared to controls. 相似文献
49.
B. K. Davis 《Cellular and molecular life sciences : CMLS》1970,26(5):534-535
Résumé Respectivement, les cochons d'Inde des races II et XIII immunisés répondent et ne répondent pas au poly-l-lysine conjugués. Par contre, nous savons qu'ils sont également capables de phagocyter le14C-DNP-PLL dans la mesure où le sont les cellules des exudats du péritoine. 相似文献
50.
Zusammenfassung Pentachlorophenylaktivierte Ester von N-Carbobenzoxy-aminosäuren verbinden sich in guten Ausbeuten mit Dicyclohexylaminsalzen von Aminosäuren. Um die Hydrolyse zu vermeiden, wurde eine Kombination der Methoden der gemischten Anhydriden und pentachlorophenylaktivierten Estern zur Verlängerung der Peptidenketten benützt. 相似文献