Fission yeast mutants affecting telomere clustering and meiosis-specific spindle pole body integrity.
In meiotic prophase of many eukaryotic organisms, telomeres attach to the nuclear envelope and form a polarized configuration called the bouquet. Bouquet formation is hypothesized to facilitate homologous chromosome pairing. In fission yeast, bouquet formation and telomere clustering occurs in karyogamy and persists throughout the horsetail stage. Here we report the isolation and characterization of six mutants from our screen for meiotic mutants. These mutants show defective telomere clustering as demonstrated by mislocalization of Swi6::GFP, a heterochromatin-binding protein, and Taz1p::GFP, a telomere-specific protein. These mutants define four complementation groups and are named dot1 to dot4-defective organization of telomeres. dot3 and dot4 are allelic to mat1-Mm and mei4, respectively. Immunolocalization of Sad1, a protein associated with the spindle pole body (SPB), in dot mutants showed an elevated frequency of multiple Sad1-nuclei signals relative to wild type. Many of these Sad1 foci were colocalized with Taz1::GFP. Impaired SPB structure and function were further demonstrated by failure of spore wall formation in dot1, by multiple Pcp1::GFP signals (an SPB component) in dot2, and by abnormal microtubule organizations during meiosis in dot mutants. The coincidence of impaired SPB functions with defective telomere clustering suggests a link between the SPB and the telomere cluster.
Jin
Ye
Y
Department of Molecular and Cell Biology, University of California, Berkeley, California 94732, USA.
Uzawa
Satoru
S
Cande
W Z
WZ
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D008540:Meiosis / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins; D008941:Spindle Apparatus / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism*; D034501:Telomere-Binding Proteins; D014157:Transcription Factors; D043222:Ubiquitin Thiolesterase
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D008164:Luminescent Proteins; C489538:MEI4 protein, S cerevisiae; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; C093512:SAD1 protein, S pombe; C075111:SWI6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D034501:Telomere-Binding Proteins; D014157:Transcription Factors; C489539:mei4 protein, S pombe; C454082:pcp1 protein, S pombe; C104344:taz1 protein, S pombe; D049452:Green Fluorescent Proteins; C403282:UBP10 protein, S cerevisiae; D043222:Ubiquitin Thiolesterase