PAT1, an evolutionarily conserved acetyltransferase homologue, is required for multiple steps in the cell cycle.
BACKGROUND
Acetylation has been implicated in many biological processes. Mutations in N-terminal acetyltransferases have been shown to cause a variety of phenotypes in Saccharomyces cerevisiae including activation of heterochromatin, inability to enter G0, and lethality. Histone acetylation has been shown to play a role in transcription regulation, histone deposition and histone displacement during spermatogenesis, although no known histone acetyltransferase is essential.


RESULTS
Studies aimed at revealing a role for histone H1 in yeast have uncovered a mutation in a putative acetyltransferase, PAT1. The mutant (pat1-1) cells can live only in the presence of vertebrate H1. PAT1 is essential for mitotic growth in S. cerevisiae; mutant cells depleted of the Pat1p show aberrant cellular and nuclear morphology. PAT1 is required for multiple cell cycle events, including passage through START, DNA synthesis, and proper mitosis through a microtubule-mediated process. The S. pombe PAT1 gene was cloned by complementation and shown to exist as part of a larger protein, the unique portion of which is homologous to a second S. cerevisiae gene. pat1 mutants show a variety of mitotic defects including enhanced chromosome loss, accumulation of multiple nuclei, generation of giant cells, and displays classical cut phenotypes in which cytokinesis occurs in the absence of proper nuclear division and segregation.


CONCLUSIONS
PAT1 controls multiple processes in cell cycle progression which suggests an essential role for the acetylation of yet unknown substrate(s).
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Verna and Marrs McLean Department of Biochemistry, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030, USA.
Allis
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Elledge
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D000123:Acetyltransferases / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001542:Benomyl / Q000494:pharmacology; D002453:Cell Cycle / Q000235:genetics*; D002645:Chickens; D003001:Cloning, Molecular; D004261:DNA Replication; D005800:Genes, Fungal / Q000235:genetics; D005816:Genetic Complementation Test; D006657:Histones / Q000235:genetics; D008870:Microtubules / Q000187:drug effects; D008938:Mitosis; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology*; D012568:Schizosaccharomyces / Q000201:enzymology*; D008941:Spindle Apparatus / Q000235:genetics; D013489:Suppression, Genetic; D013696:Temperature
D006657:Histones; D000123:Acetyltransferases; D001542:Benomyl