排序方式: 共有104条查询结果,搜索用时 953 毫秒
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We present a miniaturized pull-down method for the detection of protein-protein interactions using standard affinity chromatography reagents. Binding events between different proteins, which are color-coded with quantum dots (QDs), are visualized on single affinity chromatography beads by fluorescence microscopy. The use of QDs for single molecule detection allows the simultaneous analysis of multiple protein-protein binding events and reduces the amount of time and material needed to perform a pull-down experiment. 相似文献
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The life cycle of the metazoan nuclear envelope 总被引:1,自引:0,他引:1
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Nuclear import of the two uracil-rich small nuclear ribonucleoprotein (U snRNP) components U1A and U2B" is mediated by unusually long and complex nuclear localization signals (NLSs). Here we investigate nuclear import of U1A and U2B" in vitro and demonstrate that it occurs by an active, saturable process. Several lines of evidence suggest that import of the two proteins occurs by an import mechanism different to those characterized previously. No cross competition is seen with a variety of previously studied NLSs. In contrast to import mediated by members of the importin-beta family of nucleocytoplasmic transport receptors, U1A/U2B" import is not inhibited by either nonhydrolyzable guanosine triphosphate (GTP) analogues or by a mutant of the GTPase Ran that is incapable of GTP hydrolysis. Adenosine triphosphate is capable of supporting U1A and U2B" import, whereas neither nonhydrolyzable adenosine triphosphate analogues nor GTP can do so. U1A and U2B" import in vitro does not require the addition of soluble cytosolic proteins, but a factor or factors required for U1A and U2B" import remains tightly associated with the nuclear fraction of conventionally permeabilized cells. This activity can be solubilized in the presence of elevated MgCl(2). These data suggest that U1A and U2B" import into the nucleus occurs by a hitherto uncharacterized mechanism. 相似文献
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Biased mutations and microsatellite variation 总被引:10,自引:6,他引:4
Mutation bias is one of the forces that may constrain the variation at
microsatellite loci. Here, we study the dynamics of population statistics
and the genetic distance between two populations under multiple stepwise
mutations with linear bias and random drift. Expressions are derived for
these statistics as functions of time, as well as at mutation-drift
equilibrium. Applying these expressions to published data on humans and
chimpanzees, the regression coefficient of mutation bias on allele size was
estimated to be at least between - 0.0064 and -0.013. The assumption of
mutational bias produces larger estimates of divergence times than are
obtained in its absence; in particular, the time of split between African
and non-African human populations is estimated to be between 183,000 and
222,000 years, assuming one-step mutations and no selection. With multistep
mutations, the divergence time is estimated to be lower.
相似文献
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Sarah V Holdridge Stacey A Armstrong Anna MW Taylor Catherine M Cahill 《Molecular pain》2007,3(1):1-8
The molecular identity and pharmacological properties of mechanically gated ion channels in sensory neurons are poorly understood. We show that FM1-43, a styryl dye used to fluorescently label cell membranes, permeates mechanosensitive ion channels in cultured dorsal root ganglion neurons, resulting in blockade of three previously defined subtypes of mechanically activated currents. Blockade and dye uptake is voltage dependent and regulated by external Ca2+. The structurally related larger dye FM3-25 inhibited mechanically activated currents to a lesser degree and did not permeate the channels. In vivo, FMI-43 decreases pain sensitivity in the Randall-Selitto test and increases the withdrawal threshold from von Frey hairs, together suggesting that the channels expressed at the cell body in culture mediate mechanosensation in the intact animal. These data give further insight into the mechanosensitive ion channels expressed by somatosensory neurons and suggest FM dyes are an interesting tool for studying them. 相似文献
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Franz C Walczak R Yavuz S Santarella R Gentzel M Askjaer P Galy V Hetzer M Mattaj IW Antonin W 《EMBO reports》2007,8(2):165-172
The metazoan nuclear envelope (NE) breaks down and re-forms during each cell cycle. Nuclear pore complexes (NPCs), which allow nucleocytoplasmic transport during interphase, assemble into the re-forming NE at the end of mitosis. Using in vitro NE assembly, we show that the vertebrate homologue of MEL-28 (maternal effect lethal), a recently discovered NE component in Caenorhabditis elegans, functions in postmitotic NPC assembly. MEL-28 interacts with the Nup107-160 complex (Nup for nucleoporin), an important building block of the NPC, and is essential for the recruitment of the Nup107-160 complex to chromatin. We suggest that MEL-28 acts as a seeding point for NPC assembly. 相似文献
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