In vivo analysis of the functions of gamma-tubulin-complex proteins.
To enhance our understanding of the function(s) of gamma-tubulin-complex proteins (GCPs), we identified and analyzed the functions of the Aspergillus nidulans homologs of GCP2-GCP6 (here designated GCPB-GCBF). The gamma-tubulin small complex (gamma-TuSC) components, gamma-tubulin, GCPB and GCPC, are essential for viability and mitotic spindle formation, whereas GCPD-GCPF are not essential for viability, spindle formation or sexual reproduction. GCPD-GCPF function in reducing the frequency of chromosome mis-segregation and in the assembly of large gamma-tubulin complexes. Deletion of any of the gamma-TuSC components eliminates the localization of all GCPs to the spindle pole body (SPB), whereas deletion of GCPD-GCPF does not affect localization of gamma-TuSC components. Thus, GCPD-GCPF do not tether the gamma-TuSC to the SPB, but, rather, the gamma-TuSC tethers them to the SPB. GCPD-GCPF exhibit a hierarchy of localization to the SPB. Deletion of GCPF eliminates GCPD-GCPE localization to the SPB, and deletion of GCPD eliminates GCPE (but not GCPF) localization. All GCPs localize normally in a GCPE deletion. We propose a model for the structure of the gamma-tubulin complex and its attachment to polar microtubule organizing centers.
Xiong
Yi
Y
Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA.
Oakley
Berl R
BR
D001233:Aspergillus nidulans / Q000378:metabolism* / Q000648:ultrastructure*; D020090:Chromosome Segregation / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D018390:Gene Targeting; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics; D022101:Microtubule-Organizing Center / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology; D008941:Spindle Apparatus / Q000378:metabolism*; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*
D005656:Fungal Proteins; D008869:Microtubule-Associated Proteins; D046912:Multiprotein Complexes; C112305:TUBGCP2 protein, human; C112306:TUBGCP3 protein, human; C401398:TUBGCP4 protein, human; C444455:TUBGCP5 protein, human; C444456:TUBGCP6 protein, human; D014404:Tubulin