Caenorhabditis elegans TAC-1 and ZYG-9 form a complex that is essential for long astral and spindle microtubules

Curr Biol. 2003 Sep 2;13(17):1506-11. doi: 10.1016/s0960-9822(03)00597-9.


TACC (transforming acidic coiled-coil) proteins were first identified by their ability to transform cell lines [1], and links between human cancer and the overexpression of TACC proteins highlight the importance of understanding the biological function of this family of proteins. Herein, we describe the characterization of a new member of the TACC family of proteins in Caenorhabditis elegans, TAC-1. In other systems, TACC proteins associate with the XMAP215 family of microtubule-stabilizing proteins; however, it is unclear whether TACC proteins have microtubule-based functions distinct from XMAP215. We depleted both the XMAP215 ortholog ZYG-9 and TAC-1 via dsRNA-mediated interference (RNAi). We found that tac-1(RNAi) resulted in microtubule-based defects that were very similar to zyg-9(RNAi). Furthermore, TAC-1 and ZYG-9 are required for long astral microtubules in general and long spindle microtubules during spindle assembly. Loss of either protein did not affect the alpha-tubulin immunofluorescence intensity near centrosomes; this finding suggests that microtubule nucleation was not compromised. Both proteins localize to centrosomes and the kinetochore/microtubule region of chromosomes in metaphase and early anaphase. Furthermore, we found that ZYG-9 and TAC-1 physically interact in vivo, and this interaction is important for the efficient localization of the ZYG-9/TAC-1 complex to centrosomes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / metabolism
  • Cell Cycle / physiology
  • Centrosome / metabolism*
  • Fluorescent Antibody Technique
  • Microtubule-Associated Proteins / metabolism*
  • Microtubules / metabolism*
  • Precipitin Tests
  • RNA Interference
  • Spindle Apparatus / metabolism*


  • Microtubule-Associated Proteins