De novo heterozygous missense variants in the γ-tubulin gene TUBG1 have been linked to human malformations of cortical development associated with intellectual disability and epilepsy. Here, we investigated through in-utero electroporation and in-vivo studies, how four of these variants affect cortical development. We show that TUBG1 mutants affect neuronal positioning, disrupting the locomotion of new-born neurons but without affecting progenitors' proliferation. We further demonstrate that pathogenic TUBG1 variants are linked to reduced microtubule dynamics but without major structural nor functional centrosome defects in subject-derived fibroblasts. Additionally, we developed a knock-in Tubg1Y92C/+ mouse model and assessed consequences of the mutation. Although centrosomal positioning in bipolar neurons is correct, they fail to initiate locomotion. Furthermore, Tubg1Y92C/+ animals show neuroanatomical and behavioral defects and increased epileptic cortical activity. We show that Tubg1Y92C/+ mice partially mimic the human phenotype and therefore represent a relevant model for further investigations of the physiopathology of cortical malformations.

• MeSH
• centrozom metabolismus   MeSH
• chování zvířat MeSH
• elektronová mikroskopie MeSH
• embryo savčí MeSH
• epilepsie genetika   MeSH
• fibroblasty cytologie   metabolismus   ultrastruktura   MeSH
• genetická predispozice k nemoci MeSH
• genový knockin MeSH
• HeLa buňky MeSH
• intravitální mikroskopie MeSH
• konfokální mikroskopie MeSH
• lidé MeSH
• malformace mozkové kůry genetika   MeSH
• mikrotubuly genetika   metabolismus   MeSH
• missense mutace MeSH
• modely nemocí na zvířatech MeSH
• mozková kůra abnormality   cytologie   diagnostické zobrazování   MeSH
• myši transgenní MeSH
• myši MeSH
• neurogeneze genetika   MeSH
• neurony fyziologie   MeSH
• pohyb buněk genetika   MeSH
• tubulin genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• audiovizuální média MeSH
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• TUBG1 protein, human MeSH Prohlížeč
• TUBG1 protein, mouse MeSH Prohlížeč
• tubulin MeSH

The microtubule cytoskeleton is critically important for spatio-temporal organization of eukaryotic cells. The nucleation of new microtubules is typically restricted to microtubule organizing centers (MTOCs) and requires γ-tubulin that assembles into multisubunit complexes of various sizes. γ-Tubulin ring complexes (TuRCs) are efficient microtubule nucleators and are associated with large number of targeting, activating and modulating proteins. γ-Tubulin-dependent nucleation of microtubules occurs both from canonical MTOCs, such as spindle pole bodies and centrosomes, and additional sites such as Golgi apparatus, nuclear envelope, plasma membrane-associated sites, chromatin and surface of pre-existing microtubules. Despite many advances in structure of γ-tubulin complexes and characterization of γTuRC interacting factors, regulatory mechanisms of microtubule nucleation are not fully understood. Here, we review recent work on the factors and regulatory mechanisms that are involved in centrosomal and non-centrosomal microtubule nucleation.

• Klíčová slova
• Centrosomes, Microtubule nucleation, Microtubule-organizing centers, Non-centrosomal nucleation sites, Spindle pole bodies, γ-Tubulin complexes,
• MeSH
• centrozom metabolismus   MeSH
• Golgiho aparát metabolismus   MeSH
• jaderný obal metabolismus   MeSH
• lidé MeSH
• mikrotubuly metabolismus   MeSH
• multiproteinové komplexy metabolismus   MeSH
• pólová tělíska vřeténka metabolismus   MeSH
• proteiny asociované s mikrotubuly metabolismus   MeSH
• tubulin metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• multiproteinové komplexy MeSH
• proteiny asociované s mikrotubuly MeSH
• tubulin MeSH

gamma-Tubulin is necessary for nucleation and polar orientation of microtubules in vivo. The molecular mechanism of microtubule nucleation by gamma-tubulin and the regulation of this process are not fully understood. Here we show that there are two gamma-tubulin forms in the brain that are present in complexes of various sizes. Large complexes tend to dissociate in the presence of a high salt concentration. Both gamma-tubulins co-polymerized with tubulin dimers, and multiple gamma-tubulin bands were identified in microtubule protein preparations under conditions of non-denaturing electrophoresis. Immunoprecipitation experiments with monoclonal antibodies against gamma-tubulin and alpha-tubulin revealed interactions of both gamma-tubulin forms with tubulin dimers, irrespective of the size of complexes. We suggest that, besides small and large gamma-tubulin complexes, other molecular gamma-tubulin form(s) exist in brain extracts. Two-dimensional electrophoresis revealed multiple charge variants of gamma-tubulin in both brain extracts and microtubule protein preparations. Post-translational modification(s) of gamma-tubulins might therefore have an important role in the regulation of microtubule nucleation in neuronal cells.

• MeSH
• dimerizace MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• frakcionace buněk MeSH
• mozek - chemie * MeSH
• prasata MeSH
• protein - isoformy MeSH
• tkáňové extrakty chemie   metabolismus   MeSH
• tubulin chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protein - isoformy MeSH
• tkáňové extrakty MeSH
• tubulin MeSH

Neither the molecular mechanism by which plant microtubules nucleate in the cytoplasm nor the organization of plant mitotic spindles, which lack centrosomes, is well understood. Here, using immunolocalization and cell fractionation techniques, we provide evidence that gamma-tubulin, a universal component of microtubule organizing centers, is present in both the cytoplasm and the nucleus of plant cells. The amount of gamma-tubulin in nuclei increased during the G(2) phase, when cells are synchronized or sorted for particular phases of the cell cycle. gamma-Tubulin appeared on prekinetochores before preprophase arrest caused by inhibition of the cyclin-dependent kinase and before prekinetochore labeling of the mitosis-specific phosphoepitope MPM2. The association of nuclear gamma-tubulin with chromatin displayed moderately strong affinity, as shown by its release after DNase treatment and by using extraction experiments. Subcellular compartmentalization of gamma-tubulin might be an important factor in the organization of plant-specific microtubule arrays and acentriolar mitotic spindles.

• MeSH
• buněčné jádro chemie   MeSH
• buněčný cyklus MeSH
• centrioly MeSH
• Fabaceae chemie   metabolismus   MeSH
• fluorescenční protilátková technika MeSH
• konfokální mikroskopie MeSH
• léčivé rostliny MeSH
• mitóza * MeSH
• rostliny chemie   metabolismus   MeSH
• tubulin metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• tubulin MeSH