The lysine-rich C-terminal repeats of the centromere-binding factor 5 (Cbf5) ofKluyveromyces lactis are not essential for function
✍ Scribed by Winkler, A. A.; Bobok, A.; Zonneveld, B. J. M.; Steensma, H. Y.; Hooykaas, P. J. J.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 219 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0749-503X
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✦ Synopsis
The gene coding for the centromere-binding factor 5 (CBF5) of Kluyveromyces lactis has been isolated by hybridization of a Saccharomyces cerevisiae CBF5 DNA probe to a K. lactis library. The amino acid sequence of KlCbf5 is highly homologous, 88% identity, to ScCbf5, but also to the rat protein Nap57 (64% identity). The main difference between both yeast proteins and the rat protein is the presence of a lysine-rich domain with KKE/D repeats in the C-terminal part of the protein. These repeats are thought to be involved in binding of the protein to microtubules. Deletion of the KKE/D domain in KlCbf5 however, has no discernible effect on growth on rich medium, sensitivity to the microtubule-destabilizing drug benomyl or segregation of a reporter plasmid. On the other hand, insertion of two leucine residues adjacent to the KKE domain increases the loss rate of a reporter plasmid. In both yeasts complementation of a lethal CBF5 disruption with the heterologous gene results in a slight increase in benomyl sensitivity. A possible role of CBF5 in chromosome segregation will be discussed.