Meiotic segregation, synapsis, and recombination checkpoint functions require physical interaction between the chromosomal proteins Red1p and Hop1p.
In yeast, HOP1 and RED1 are required during meiosis for proper chromosome segregation and the consequent formation of viable spores. Mutations in either HOP1 or RED1 create unique as well as overlapping phenotypes, indicating that the two proteins act alone as well as in concert with each other. To understand which meiotic processes specifically require Red1p-Hop1p hetero-oligomers, a novel genetic screen was used to identify a single-point mutation of RED1, red1-K348E, that separates Hop1p binding from Red1p homo-oligomerization. The Red1-K348E protein is stable, phosphorylated in a manner equivalent to Red1p, and undergoes efficient homo-oligomerization; however, its ability to interact with Hop1p both by two-hybrid and coimmunoprecipitation assays is greatly reduced. Overexpression of HOP1 specifically suppresses red1-K348E, supporting the idea that the only defect in the protein is a reduced affinity for Hop1p. red1-K348E mutants exhibit reduced levels of crossing over and spore viability and fail to undergo chromosome synapsis, thereby implicating a role for Red1p-Hop1p hetero-oligomers in these processes. Furthermore, red1-K348E suppresses the sae2/com1 defects in meiotic progression and sporulation, indicating a previously unknown role for HOP1 in the meiotic recombination checkpoint.
Woltering
D
D
Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, State University of New York at Stony Brook, 11794-5215, USA.
Baumgartner
B
B
Bagchi
S
S
Larkin
B
B
Loidl
J
J
de los Santos
T
T
Hollingsworth
N M
NM
D000483:Alleles; D000596:Amino Acids; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D020090:Chromosome Segregation / Q000235:genetics / Q000502:physiology*; D015825:Chromosomes, Fungal / Q000502:physiology*; D003434:Crossing Over, Genetic; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004720:Endonucleases; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015870:Gene Expression; D008540:Meiosis / Q000502:physiology*; D016296:Mutagenesis; D009842:Oligopeptides / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013172:Spores, Fungal / Q000502:physiology; D000099160:LexA Repressor Protein
D000596:Amino Acids; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D004720:Endonucleases; D005656:Fungal Proteins; D009842:Oligopeptides; D029701:Saccharomyces cerevisiae Proteins; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein; C086672:HOP1 protein, S cerevisiae; C086673:RED1 protein, S cerevisiae; C107849:SAE2 protein, S cerevisiae