Cytoplasmic dynein is required to oppose the force that moves nuclei towards the hyphal tip in the filamentous ascomycete Ashbya gossypii.

Published

Journal Article

We have followed the migration of GFP-labelled nuclei in multinucleate hyphae of Ashbya gossypii. For the first time we could demonstrate that the mode of long range nuclear migration consists of oscillatory movements of nuclei with, on average, higher amplitudes in the direction of the growing tip. We could also show that mitotic division proceeds at a constant rate of 0. 64 microm/minute which differs from the biphasic kinetics described for the yeast Saccharomyces cerevisiae. Furthermore we were able to identify the microtubule-based motor dynein as a key element in the control of long range nuclear migration. For other filamentous fungi it had already been demonstrated that inactivating mutations in dynein led to severe problems in nuclear migration, i.e. generation of long nuclei-free hyphal tips and clusters of nuclei throughout the hyphae. This phenotype supported the view that dynein is important for the movement of nuclei towards the tip. In A. gossypii the opposite seems to be the case. A complete deletion of the dynein heavy chain gene leads to nuclear clusters exclusively at the hyphal tips and to an essentially nucleus-free network of hyphal tubes and branches. Anucleate hyphae and branches in the vicinity of nuclear clusters show actin cables and polarized actin patches, as well as microtubules. The slow growth of this dynein null mutant could be completely reverted to wild-type-like growth in the presence of benomyl, which can be explained by the observed redistribution of nuclei in the hyphal network.

Full Text

Duke Authors

Cited Authors

  • Alberti-Segui, C; Dietrich, F; Altmann-Jöhl, R; Hoepfner, D; Philippsen, P

Published Date

  • March 2001

Published In

Volume / Issue

  • 114 / Pt 5

Start / End Page

  • 975 - 986

PubMed ID

  • 11181180

Pubmed Central ID

  • 11181180

International Standard Serial Number (ISSN)

  • 0021-9533

Language

  • eng

Conference Location

  • England