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Cytoplasmic dynein is required for normal nuclear segregation in yeast
D Eshel1, L A Urrestarazu, S Vissers
1Pacific Biomedical Research Center, University of Hawaii, Honolulu 96822.
Abstract:
We have identified the gene DYN1, which encodes the heavy chain of cytoplasmic dynein in the yeast Saccharomyces cerevisiae. The predicted amino acid sequence (M(r) 471,305) reveals the presence of four P-loop motifs, as in all dyneins known so far, and has 28% overall identity to the dynein heavy chain of Dictyostelium [Koonce, M. P., Grissom, P. M. & McIntosh, J. R. (1992) J. Cell Biol. 119, 1597-1604] with 40% identity in the putative motor domain. Disruption of DYN1 causes misalignment of the spindle relative to the bud neck during cell division and results in abnormal distribution of the dividing nuclei between the mother cell and the bud. Cytoplasmic dynein, by generating force along cytoplasmic microtubules, may play an important role in the proper alignment of the mitotic spindle in yeast.
Insights
Researchers identified the yeast gene DYN1, encoding cytoplasmic dynein. Disruption of this gene leads to spindle misalignment and abnormal nuclear distribution during cell division in Saccharomyces cerevisiae.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Cytoplasmic dynein is a motor protein complex crucial for intracellular transport and cell division.
- Understanding the specific genes encoding dynein components is essential for elucidating its cellular functions.
Purpose of the Study:
- To identify and characterize the gene encoding the heavy chain of cytoplasmic dynein in the yeast Saccharomyces cerevisiae.
- To investigate the role of this dynein heavy chain in cell division processes.
Main Methods:
- Gene identification and sequencing of DYN1 in Saccharomyces cerevisiae.
- Bioinformatic analysis of the predicted amino acid sequence, including identification of conserved motifs and comparison with other dyneins.
- Gene disruption experiments to assess the phenotypic consequences of DYN1 loss.
Main Results:
- The gene DYN1 was identified, encoding a heavy chain of cytoplasmic dynein with a predicted molecular mass of 471,305 Da.
- The predicted protein sequence contains four P-loop motifs and shows significant identity to Dictyostelium dynein heavy chain, particularly in the motor domain.
- Disruption of DYN1 resulted in spindle misalignment relative to the bud neck and abnormal nuclear distribution during cell division.
Conclusions:
- The DYN1 gene encodes the heavy chain of cytoplasmic dynein in Saccharomyces cerevisiae.
- Cytoplasmic dynein, mediated by DYN1, plays a critical role in the proper alignment of the mitotic spindle during yeast cell division.
- This finding contributes to understanding the mechanics of nuclear positioning and segregation in eukaryotic cells.