Fission yeast Arp6 is required for telomere silencing, but functions independently of Swi6.
The actin-related proteins (Arps), which are subdivided into at least eight subfamilies, are conserved from yeast to humans. A member of the Arp6 subfamily in Drosophila, Arp4/Arp6, co-localizes with heterochromatin protein 1 (HP1) in pericentric heterochromatin. Fission yeast Schizosaccharomyces pombe possesses both an HP1 homolog and an Arp6 homolog. However, the function of S.pombe Arp6 has not been characterized yet. We found that deletion of arp6(+) impaired telomere silencing, but did not affect centromere silencing. Chromatin immunoprecipitation assays revealed that Arp6 bound to the telomere region. However, unlike Drosophila Arp4/Arp6, S.pombe Arp6 was distributed throughout nuclei. The binding of Arp6 to telomere DNA was not affected by deletion of swi6(+). Moreover, the binding of Swi6 to telomere ends was not affected by deletion of arp6(+). These results suggest that Arp6 and Swi6 function independently at telomere ends. We propose that the Arp6-mediated repression mechanism works side by side with Swi6-based telomere silencing in S.pombe.
Ueno
Masaru
M
Department of Chemistry, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan. scmueno@ipc.shizuoka.ac.jp
Murase
Tadashi
T
Kibe
Tatsuya
T
Ohashi
Noriyuki
N
Tomita
Kazunori
K
Murakami
Yota
Y
Uritani
Masahiro
M
Ushimaru
Takashi
T
Harata
Masahiko
M
D000199:Actins / Q000235:genetics / Q000378:metabolism*; D021581:Active Transport, Cell Nucleus; D002467:Cell Nucleus / Q000378:metabolism; D002503:Centromere / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D020868:Gene Silencing; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000235:genetics* / Q000378:metabolism*; D034501:Telomere-Binding Proteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
D000199:Actins; C498984:Arp6 protein, S pombe; D002868:Chromosomal Proteins, Non-Histone; D006570:Heterochromatin; D012331:RNA, Fungal; D029702:Schizosaccharomyces pombe Proteins; C465958:Swi6 protein, S pombe; D034501:Telomere-Binding Proteins; C104344:taz1 protein, S pombe