RESUMEN

The large subunit of Saccharomyces cerevisiae DNA polymerase epsilon, Pol2, comprises two essential functions. The N terminus has essential DNA polymerase activity. The C terminus is also essential, but its function is unknown. We report here that the C-terminal domain of Pol2 interacts with polymerase sigma (Pol sigma), a recently identified, essential nuclear nucleotidyl transferase encoded by two redundant genes, TRF4 and TRF5. This interaction is functional, since Pol sigma stimulates the polymerase activity of the Pol epsilon holoenzyme significantly. Since Trf4 is required for sister chromatid cohesion as well as for completion of S phase and repair, the interaction suggested that Pol epsilon, like Pol sigma, might form a link between the replication apparatus and sister chromatid cohesion and/or repair machinery. We present evidence that pol2 mutants are defective in sister chromatid cohesion. In addition, Pol2 interacts with SMC1, a subunit of the cohesin complex, and with ECO1/CTF7, required for establishing sister chromatid cohesion; and pol2 mutations act synergistically with smc1 and scc1. We also show that trf5 Delta mutants, like trf4 Delta mutants, are defective in DNA repair and sister chromatid cohesion.

Asunto(s)

ADN Nucleotidiltransferasas/metabolismo , ADN Polimerasa II/metabolismo , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Sitios de Unión , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Línea Celular , Cromátides/fisiología , Proteínas Cromosómicas no Histona/química , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , ADN Nucleotidiltransferasas/química , ADN Nucleotidiltransferasas/genética , ADN Polimerasa II/química , ADN Polimerasa II/genética , Reparación del ADN , ADN de Hongos/biosíntesis , ADN de Hongos/genética , ADN Polimerasa Dirigida por ADN/química , ADN Polimerasa Dirigida por ADN/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Genes Fúngicos , Datos de Secuencia Molecular , Mutación , Proteínas Nucleares/química , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Plásmidos/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Homología de Secuencia de Aminoácido , Técnicas del Sistema de Dos Híbridos