Send to

Choose Destination
Dev Biol. 1994 Jan;161(1):131-40.

Gamma-tubulin is asymmetrically distributed in the cortex of Xenopus oocytes.

Author information

Department of Biology, University of Utah, Salt Lake City 84112.


Stage VI Xenopus oocytes contain an extensive network of cytoplasmic microtubules (MTs), with no evidence of a functional centrosome. Recently, Stearns et al. (1991) demonstrated that Xenopus eggs contain a substantial pool of the centrosomal protein gamma-tubulin (gamma-Tb). For this report, I have used confocal immunofluorescence microscopy to examine the distribution of gamma-Tb during the later stages of oogenesis in Xenopus laevis. gamma-Tb was apparent surrounding the germinal vesicle (GV) of stage VI oocytes, consistent with previous results suggesting that the GV serves as an microtubule organizing center in later oogenesis. Surprisingly, gamma-Tb was also concentrated in the cortex of stage VI oocytes, and the distribution of cortical gamma-Tb was polarized along the animal-vegetal (A-V) axis. In the vegetal cortex, gamma-Tb was observed in brightly stained foci, often organized into short linear arrays. In the animal hemisphere, gamma-Tb was more evenly distributed as small cortical foci. Dual immunofluorescence microscopy revealed that gamma-Tb in the vegetal hemisphere was associated with MTs in the cortical cytoplasm. The distribution of gamma-Tb was not significantly affected by either cold or nocodazole, but was partially disrupted by cytochalasin B. gamma-Tb thus may serve as a link between the oocyte MT network and cortical actin. Finally, polarization of the distribution of cortical gamma-Tb temporally coincides with formation of the A-V axis and polarization of the oocyte MT cytoskeleton during stage IV of oogenesis. These observations raise a number of questions regarding the organization and orientation of MTs during Xenopus oogenesis and the role of gamma-Tb in the polarization of the oocyte cytoskeleton during A-V axis formation.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center