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The dominant-negative female-sterile KavarD mutations and their revertant kavarr alleles identify the Tubulin67C gene of Drosophila melanogaster, which codes for the maternally provided -tubulin4 isoform. The mutations result in the formation of monopolar, collapsed spindles (each with two nearby centrosomes, a tassel of microtubules and overcondensed chromosomes), thus revealing a novel function for -tubulin4 in spindle maintenance and elongation. Molecular features of the two KavarD alleles and a kavarnull allele are described and models for their actions are discussed. 相似文献
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Jana Chumová Lucie Trögelová Hana Kourová Jindřich Volc Vadym Sulimenko Petr Halada Ondřej Kučera Oldřich Benada Anna Kuchařová Anastasiya Klebanovych Pavel Dráber Geoffrey Daniel Pavla Binarová 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2018,1865(5):734-748
γ-Tubulin is essential for microtubule nucleation and also plays less understood roles in nuclear and cell-cycle-related functions. High abundancy of γ-tubulin in acentrosomal Arabidopsis cells facilitated purification and biochemical characterization of large molecular species of γ-tubulin. TEM, fluorescence, and atomic force microscopy of purified high molecular γ-tubulin forms revealed the presence of linear filaments with a double protofilament substructure, filament bundles and aggregates. Filament formation from highly purified γ-tubulin free of γ-tubulin complex proteins (GCPs) was demonstrated for both plant and human γ-tubulin. Moreover, γ-tubulin associated with porcine brain microtubules formed oligomers. Experimental evidence on the intrinsic ability of γ-tubulin to oligomerize/polymerize was supported by conservation of α- and β-tubulin interfaces for longitudinal and lateral interactions for γ-tubulins. STED (stimulated emission depletion) microscopy of Arabidopsis cells revealed fine, short γ-tubulin fibrillar structures enriched on mitotic microtubular arrays that accumulated at polar regions of acentrosomal spindles and the outer nuclear envelope before mitosis, and were also present in nuclei. Fine fibrillar structures of γ-tubulin representing assemblies of higher order were localized in cell-cycle-dependent manner at sites of dispersed γ-tubulin location in acentrosomal plant cells as well as at sites of local γ-tubulin enrichment after drug treatment. Our findings that γ-tubulin preserves the capability of prokaryotic tubulins to self-organize into filaments assembling by lateral interaction into bundles/clusters help understanding of the relationship between structure and multiple cellular functions of this protein species and suggest that besides microtubule nucleation and organization, γ-tubulin may also have scaffolding or sequestration functions. 相似文献
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The optic nerve of the bullfrog was transected and the regeneration process was investigated. We previously reported that alpha-tubulin mRNA in the retina increased to a maximum 1-2 h after optic nerve transection with no specific change in actin mRNA. In the present investigation, we examined the long-term effect of optic nerve transection. Northern blot analysis revealed that alpha-tubulin mRNA increased again gradually after the rapid and transient increase and actin mRNA increased to a maximum at 7 days (more than twofold compared to the control retinas). The period during which actin mRNA reaches a maximal increase almost corresponds to the time lag between the axotomy and the initiation of axonal outgrowth. The main cytoskeletons of neuronal growth cones have been shown to consist of actin-containing microfilaments. Therefore, the transient increase of actin mRNA may have a relationship to the initial outgrowth of axons. On the other hand, the rapid and transient increase of alpha-tubulin mRNA observed in our previous studies is probably one of the initial responses of retinal ganglion cells to the axotomy, and the gradual increase in alpha-tubulin mRNA observed in this study can probably be interpreted as provision of the structural materials necessary for axonal elongation. 相似文献
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Marco Aurélio Salomão Fortes Gabriel Nasri Marzuca-Nassr Kaio Fernando Vitzel Carlos Hermano da Justa Pinheiro Philip Newsholme Rui Curi 《Analytical biochemistry》2016
The use of Western blot analysis is of great importance in research, and the measurement of housekeeping proteins is commonly used for loading controls. However, Ponceau S staining has been shown to be an alternative to analysis of housekeeping protein levels as loading controls in some conditions. In the current study, housekeeping protein levels were measured in skeletal muscle hypertrophy and streptozotocin-induced diabetes experimental models. The following housekeeping proteins were investigated: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-actin, α-tubulin, γ-tubulin, and α-actinin. Evidence is presented that Ponceau S is more reliable than housekeeping protein levels for specific protein quantifications in Western blot analysis. 相似文献
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Cristina Andrade-Monteiro Sandra R.C. Pombeiro-Sponchiado Nilce M. Martinez-Rossi 《FEMS microbiology letters》1994,120(1-2):183-186
Abstract Two benomyl-resistant mutants, benD3 tubC41 and benD4 tubC42 , of Aspergillus nidulans were isolated after UV treatment. The tubC mutations permitted good conidiation of these strains in culture media containing benomyl and were responsible for increasing their benomyl resistance levels. This implies that β3-tubulin, a product of the tubC gene, in addition to being involved in fungal conidiation, participates in the vegetative growth of the fungus. The tubC gene was located in linkage group I. 相似文献
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Summary. Meiosis in Aneura pinguis is preceded by extensive cytoplasmic preparation for quadripartitioning of the diploid sporocyte into a tetrad of haploid
spores. In early prophase the four future spore domains are defined by lobing of the cytoplasm and development of a quadripolar
prophase spindle focused at polar organizers (POs) centered in the lobes. Cells entering the reproductive phase become isolated
and, instead of hooplike cortical microtubules, have endoplasmic microtubule systems centered on POs. These archesporial cells
proliferate by mitosis before entering meiosis. In prophase of each mitosis, POs containing a distinct concentration of γ-tubulin
appear de novo at tips of nuclei and initiate the bipolar spindle. Cells entering meiosis become transformed into quadrilobed
sporocytes with four POs, one in each lobe. This transition is a complex process encompassing assembly of two opposite POs
which subsequently disperse into intersecting bands of microtubules that form around the central nucleus. The girdling bands
define the future planes of cytokinesis and the cytoplasm protrudes through the restrictive bands becoming quadrilobed. Two
large POs reappear in opposite cleavage furrows. Each divides and the resulting POs migrate into the tetrahedral lobes of
cytoplasm. Cones of microtubules emanating from the four POs interact to form a quadripolar microtubule system (QMS) that
surrounds the nucleus in meiotic prophase. The QMS is subsequently transformed into a functionally bipolar metaphase spindle
by migration of poles in pairs to opposite cleavage furrows. These findings contribute to knowledge of microtubule organization
and the role of microtubules in spatial regulation of cytokinesis in plants.
Correspondence and reprints: Department of Biology, University of Louisiana-Lafayette, Lafayette, LA 70504-2451, U.S.A. 相似文献
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