Fission Yeast Mutants Affecting Telomere Clustering and Meiosis-Specific Spindle Pole Body Integrity

• Published in: Genetics (Austin) Vol. 160; no. 3; pp. 861 - 876
• Main Authors: Jin, Ye, Uzawa, Satoru, Cande, W. Z
• Format: Journal Article
• Language: English
• Published: United States Genetics Soc America 01.03.2002; Genetics Society of America
• Subjects: DNA-Binding Proteins - metabolism; dot3 gene; dot4 gene; Fungal Proteins - genetics; Fungal Proteins - metabolism; Genetics; Green Fluorescent Proteins; Luminescent Proteins; mat1 gene; mei4 gene; Meiosis - physiology; Microtubules - metabolism; Mutation; Nuclear Proteins - genetics; Recombinant Fusion Proteins - genetics; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Sad1 protein; Schizosaccharomyces - genetics; Schizosaccharomyces - metabolism; Schizosaccharomyces pombe; Schizosaccharomyces pombe Proteins; Spindle Apparatus - metabolism; spindle pole body; Swi6 protein; Taz1 protein; Telomere - metabolism; Telomere-Binding Proteins; Transcription Factors; Ubiquitin Thiolesterase; Yeast
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/160.3.861

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.