Caenorhabditis elegans TAC-1 and ZYG-9 form a complex that is essential for long astral and spindle microtubules.
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.
Srayko
Martin
M
Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, D-01307, Dresden, Germany.
Quintin
Sophie
S
Schwager
Anne
A
Hyman
Anthony A
AA
D000818:Animals; D015153:Blotting, Western; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D018385:Centrosome / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D011233:Precipitin Tests; D034622:RNA Interference; D008941:Spindle Apparatus / Q000378:metabolism*
D008869:Microtubule-Associated Proteins