NEJ1 controls non-homologous end joining in Saccharomyces cerevisiae.
Broken DNA ends are rejoined by non-homologous end-joining (NHEJ) pathways requiring the Ku proteins (Ku70, Ku80), DNA ligase IV and its associated protein Lif1/Xrcc4 (ref. 1). In mammalian meiotic cells, Ku protein levels are much lower than in somatic cells, apparently reducing the capacity of meiotic cells to carry out NHEJ and thereby promoting homologous recombination. In Saccharomyces cerevisiae, NHEJ is also downregulated in meiosis-competent MATa/MAT alpha diploid cells in comparison with diploids or haploids expressing only MATa or MAT alpha. Diploids expressing both MATa and MAT alpha show enhanced mitotic homologous recombination. Here we report that mating-type-dependent regulation of NHEJ in budding yeast is caused in part by transcriptional repression of both LIF1 and the gene NEJ1 (YLR265C)--identified from microarray screening of messenger RNAs. Deleting NEJ1 reduces NHEJ 100-fold in MATa or MAT alpha haploids. Constitutive expression of NEJ1, but not expression of LIF1, restores NHEJ in MATa/MAT alpha cells. Nej1 regulates the subcellular distribution of Lif1. A green fluorescent protein (GFP)-Lif1 fusion protein accumulates in the nucleus in cells expressing NEJ1 but is largely cytoplasmic when NEJ1 is repressed.
Valencia
M
M
Rosenstiel Center and Department of Biology, Brandeis University, Waltham, Massachusetts 02454-9110, USA.
Bentele
M
M
Vaze
M B
MB
Herrmann
G
G
Kraus
E
E
Lee
S E
SE
Schär
P
P
Haber
J E
JE
D004249:DNA Damage; D004260:DNA Repair; D004271:DNA, Fungal; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D049770:Genes, Mating Type, Fungal; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins / Q000502:physiology; D008164:Luminescent Proteins / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C114091:LIF1 protein, S cerevisiae; D008164:Luminescent Proteins; C096063:MATA1 protein, S cerevisiae; C062928:MATA2 protein, S cerevisiae; C441270:NEJ1 protein, S cerevisiae; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins