Mutations synthetically lethal with cep1 target S. cerevisiae kinetochore components

Area of Science:

• * Molecular and Cellular Biology
• * Genetics and Genomics
• * Biochemistry

Background:

• * CP1 (encoded by CEP1) is a Saccharomyces cerevisiae chromatin protein.
• * CP1 binds DNA elements in centromeres and 5'-flanking regions of methionine biosynthetic (MET) genes.
• * Loss of CP1 function leads to defects in chromosome segregation and MET gene transcription.

Purpose of the Study:

• * To investigate the role of CP1 in chromatin structure and function.
• * To identify genes that interact synthetically with cep1 null mutations.
• * To elucidate the function of novel genes involved in chromosome segregation and kinetochore integrity.

Main Methods:

• * Genetic screening for mutations synthetically lethal with a cep1 null allele.
• * Analysis of chromosome segregation rates in mutant strains.
• * Complementation assays using a human cDNA to test functional homology.

Main Results:

• * A screen for cep1 synthetic lethal (csl) mutations identified five complementation groups.
• * Four csl mutations exacerbated chromosome loss in centromere-lacking marker chromosomes.
• * Three of these genes (CEP3, NDC10, CSE4) are known kinetochore components; the fourth (CSL4/YNL232w) is essential and has a human homolog.

Conclusions:

• * CP1 plays a significant role in maintaining the biochemical integrity of the kinetochore.
• * The identified CSL genes, particularly CSL4, are critical for proper chromosome segregation.
• * CP1 and its interacting partners safeguard kinetochore function in yeast.