C-terminal truncation of RAP1 results in the deregulation of telomere size, stability, and function in Saccharomyces cerevisiae.
AUTOR(ES)
Kyrion, G
RESUMO
The Saccharomyces cerevisiae DNA-binding protein RAP1 is capable of binding in vitro to sequences from a wide variety of genomic loci, including upstream activating sequence elements, the HML and HMR silencer regions, and the poly(G1-3T) tracts of telomeres. Recent biochemical and genetic studies have suggested that RAP1 physically and functionally interacts with the yeast telomere. To further investigate the role of RAP1 at the telomere, we have identified and characterized three intragenic suppressors of a temperature-sensitive allele of RAP1, rap1-5. These telomere deficiency (rap1t) alleles confer several novel phenotypes. First, telomere tract size elongates to up to 4 kb greater than sizes of wild-type or rap1-5 telomeres. Second, telomeres are highly unstable and are subject to rapid, but reversible, deletion of part or all of the increase in telomeric tract length. Telomeric deletion does not require the RAD52 or RAD1 gene product. Third, chromosome loss and nondisjunction rates are elevated 15- to 30-fold above wild-type levels. Sequencing analysis has shown that each rap1t allele contains a nonsense mutation within a discrete region between amino acids 663 and 684. Mobility shift and Western immunoblot analyses indicate that each allele produces a truncated RAP1 protein, lacking the C-terminal 144 to 165 amino acids but capable of efficient DNA binding. These data suggest that RAP1 is a central regulator of both telomere and chromosome stability and define a C-terminal domain that, while dispensable for viability, is required for these telomeric functions.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=360450Documentos Relacionados
- Mutational Analysis Defines a C-Terminal Tail Domain of Rap1 Essential for Telomeric Silencing in Saccharomyces Cerevisiae
- The C-terminal domain of Saccharomyces cerevisiae DNA topoisomerase II.
- C-terminal sequences can inhibit the insertion of membrane proteins into the endoplasmic reticulum of Saccharomyces cerevisiae.
- A Saccharomyces Cerevisiae Rad52 Allele Expressing a C-Terminal Truncation Protein: Activities and Intragenic Complementation of Missense Mutations
- Farnesyl cysteine C-terminal methyltransferase activity is dependent upon the STE14 gene product in Saccharomyces cerevisiae.