Gamma-tubulin regulates the anaphase-promoting complex/cyclosome during interphase.
A cold-sensitive gamma-tubulin allele of Aspergillus nidulans, mipAD159, causes defects in mitotic and cell cycle regulation at restrictive temperatures that are apparently independent of microtubule nucleation defects. Time-lapse microscopy of fluorescently tagged mitotic regulatory proteins reveals that cyclin B, cyclin-dependent kinase 1, and the Ancdc14 phosphatase fail to accumulate in a subset of nuclei at restrictive temperatures. These nuclei are permanently removed from the cell cycle, whereas other nuclei, in the same multinucleate cell, cycle normally, accumulating and degrading these proteins. After each mitosis, additional daughter nuclei fail to accumulate these proteins, resulting in an increase in noncycling nuclei over time and consequent inhibition of growth. Extensive analyses reveal that these noncycling nuclei result from a nuclear autonomous, microtubule-independent failure of inactivation of the anaphase-promoting complex/cyclosome. Thus, gamma-tubulin functions to regulate this key mitotic and cell cycle regulatory complex.
Nayak
Tania
T
Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA.
Edgerton-Morgan
Heather
H
Horio
Tetsuya
T
Xiong
Yi
Y
De Souza
Colin P
CP
Osmani
Stephen A
SA
Oakley
Berl R
BR
D000483:Alleles; D064173:Anaphase-Promoting Complex-Cyclosome; D001233:Aspergillus nidulans / Q000378:metabolism*; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle; D019926:Cyclin B / Q000378:metabolism; D008938:Mitosis; D009154:Mutation; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000235:genetics; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*
D019926:Cyclin B; D011993:Recombinant Fusion Proteins; D014404:Tubulin; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D016203:CDC2 Protein Kinase