Reorganization and polarization of the meiotic bouquet-stage cell can be uncoupled from telomere clustering.
Striking cellular reorganizations mark homologous pairing during meiotic prophase. We address the interdependence of chromosomal and cellular polarization during meiotic telomere clustering, the defining feature of the bouquet stage, by examining nuclear positioning and microtubule and nuclear pore reorganization. Polarization of meiotic cellular architecture was coincident with telomere clustering: microtubules were focused on the nuclear surface opposite the telomere cluster, the nucleus was positioned eccentrically in the cell such that the telomeres faced the direction of nuclear displacement and nuclear pores were clustered in a single region of the nuclear surface opposite the telomeres. Treatment of pre-bouquet stage cells with colchicine inhibited telomere clustering. Asymmetric nuclear positioning and nuclear pore clustering were normal in the presence of unclustered telomeres resulting from colchicine treatment. Nuclear pores were positioned normally with respect to the cell cortex in the absence of telomere clustering, indicating that telomere positioning is not required for polarization. This work provides evidence of meiotic cell polarization and suggests that telomeres may be positioned relative to an asymmetry present in the cell at the time of bouquet formation.
Cowan
Carrie R
CR
Department of Plant and Microbial Biology, University of California - Berkeley, Berkeley, CA 94720-3200, USA.
Carlton
Peter M
PM
Cande
W Zacheus
WZ
D002467:Cell Nucleus / Q000187:drug effects / Q000235:genetics* / Q000648:ultrastructure; D016764:Cell Polarity / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D003078:Colchicine / Q000494:pharmacology; D035264:Flowers / Q000166:cytology / Q000187:drug effects / Q000235:genetics*; D006570:Heterochromatin / Q000187:drug effects / Q000235:genetics / Q000648:ultrastructure; D008540:Meiosis / Q000187:drug effects / Q000235:genetics*; D008870:Microtubules / Q000187:drug effects / Q000235:genetics / Q000648:ultrastructure; D022022:Nuclear Pore / Q000235:genetics / Q000648:ultrastructure; D012434:Secale / Q000166:cytology / Q000235:genetics*; D016615:Telomere / Q000235:genetics* / Q000648:ultrastructure; D020691:rab GTP-Binding Proteins / Q000235:genetics
D006570:Heterochromatin; D020691:rab GTP-Binding Proteins; D003078:Colchicine