1. P. Sampaio, E. Rebollo, H. Varmark, C. E. Sunkel and C. Gonzalez (2001) Organized microtubule arrays in gamma-tubulin-depleted Drosophila spermatocytes. Curr Biol 11(22): 1788-93.
Abstract To assess the role of gamma-tubulin in spindle assembly in vivo, we have followed meiosis progression by immunofluorescence and time-lapse video microscopy in gammaTub23C(PI) mutant spermatocytes. We have found that centrosomes associate with large numbers of astral microtubules even though gamma-tubulin is severely depleted; bipolar meiotic spindles are never assembled; and later in meiosis, the microtubules get organized into a conical structure that is never observed in wild-type cells. Several lines of evidence suggest that these cones may be related to wild-type central spindles. First, they are assembled midway through meiosis and elongate during anaphase. Second, they are constricted during late meiosis, giving rise to a pointed end similar to those that form in each half of the wild-type spindle midzone. Third, Klp3A and Polo, two markers of the wild-type central spindle are also found around the pointed end of the mutant cones. Finally, ectopic cytokinesis furrows are often formed at the distal end of the cone. Our results suggest that microtubule polymerization or stabilization from the centrosome may be possible in a gamma-tubulin-independent manner in Drosophila spermatocytes. However, gamma-tubulin seems to be essential for spindle assembly in these cells. Finally, our results show that at least part of the central spindle and constriction-ring assembly machinery can operate on microtubule bundles that are not organized as bipolar spindles. PMID: [11719222]
Figures for illustrating the function of this protein/gene
Function
Tubulin is the major constituent of microtubules. Gammatubulin is found at microtubule organizing centers (MTOC) such asthe spindle poles or the centrosome, suggesting that it isinvolved in the minus-end nucleation of microtubule assembly.Required for oocyte activation and consequently for organizationof the female meiotic spindle. Essential for centrosomeorganization and assembly of biastral mitotic spindles in embryos.
CHAIN 1 457 Tubulin gamma-2 chain. /FTId=PRO_0000048455. NP_BIND 142 148 GTP (Potential). CONFLICT 282 282 T -> A (in Ref. 2; AAB52553). CONFLICT 343 343 E -> K (in Ref. 1; AAC35843). Back to Top