Expression-State Boundaries in the Mating-Type Region of Fission Yeast

Corresponding author: Geneviève Thon, Institute of Molecular Biology, University of Copenhagen, Øster Farimagsgade 2A, DK-1353 Copenhagen K, Denmark., gen{at}biobase.dk (E-mail)

Communicating editor: G. R. SMITH

A transcriptionally silent chromosomal domain is found in the mating-type region of fission yeast. Here we show that this domain is delimited by 2-kb inverted repeats, IR-L and IR-R. IR-L and IR-R prevent the expansion of transcription-permissive chromatin into the silenced region and that of silenced chromatin into the expressed region. Their insulator activity is partially orientation dependent. The silencing defects that follow deletion or inversion of IR-R are suppressed by high dosage of the chromodomain protein Swi6. Combining chromosomal deletions and Swi6 overexpression shows that IR-L and IR-R provide firm borders in a region where competition between silencing and transcriptional competence occurs. IR-R possesses autonomously replicating sequence (ARS) activity, leading to a model where replication factors, or replication itself, participate in boundary formation.

This article has been cited by other articles:

				I. Liachko and B. K. Tye Mcm10 Mediates the Interaction Between DNA Replication and Silencing Machineries Genetics, February 1, 2009; 181(2): 379 - 391. [Abstract] [Full Text] [PDF]

				M. Sadaie, R. Kawaguchi, Y. Ohtani, F. Arisaka, K. Tanaka, K. Shirahige, and J.-i. Nakayama Balance between Distinct HP1 Family Proteins Controls Heterochromatin Assembly in Fission Yeast Mol. Cell. Biol., December 1, 2008; 28(23): 6973 - 6988. [Abstract] [Full Text] [PDF]

				J. Alfredsson-Timmins, F. Henningson, and P. Bjerling The Clr4 methyltransferase determines the subnuclear localization of the mating-type region in fission yeast J. Cell Sci., June 1, 2007; 120(11): 1935 - 1943. [Abstract] [Full Text] [PDF]

				S. Isaac, J. Walfridsson, T. Zohar, D. Lazar, T. Kahan, K. Ekwall, and A. Cohen Interaction of Epe1 With the Heterochromatin Assembly Pathway in Schizosaccharomyces pombe Genetics, April 1, 2007; 175(4): 1549 - 1560. [Abstract] [Full Text] [PDF]

				M. ZOFALL and S.I.S. GREWAL RNAi-mediated Heterochromatin Assembly in Fission Yeast Cold Spring Harb Symp Quant Biol, January 1, 2006; 71(0): 487 - 496. [Abstract] [PDF]

				G. Thon, K. R. Hansen, S. P. Altes, D. Sidhu, G. Singh, J. Verhein-Hansen, M. J. Bonaduce, and A. J. S. Klar The Clr7 and Clr8 Directionality Factors and the Pcu4 Cullin Mediate Heterochromatin Formation in the Fission Yeast Schizosaccharomyces pombe Genetics, December 1, 2005; 171(4): 1583 - 1595. [Abstract] [Full Text] [PDF]

				J. Z. Dalgaard and S. Vengrova Selective Gene Expression in Multigene Families from Yeast to Mammals Sci. Signal., October 26, 2004; 2004(256): re17 - re17. [Abstract] [Full Text] [PDF]

				P. Bjerling, K. Ekwall, R. Egel, and G. Thon A novel type of silencing factor, Clr2, is necessary for transcriptional silencing at various chromosomal locations in the fission yeast Schizosaccharomyces pombe Nucleic Acids Res., August 18, 2004; 32(15): 4421 - 4428. [Abstract] [Full Text] [PDF]

				H. CAM and S.I.S. GREWAL RNA Interference and Epigenetic Control of Heterochromatin Assembly in Fission Yeast Cold Spring Harb Symp Quant Biol, January 1, 2004; 69(0): 419 - 428. [Abstract] [PDF]

				N. Ayoub, K.-i. Noma, S. Isaac, T. Kahan, S. I. S. Grewal, and A. Cohen A Novel jmjC Domain Protein Modulates Heterochromatization in Fission Yeast Mol. Cell. Biol., June 15, 2003; 23(12): 4356 - 4370. [Abstract] [Full Text] [PDF]

				J. Blanton, M. Gaszner, and P. Schedl Protein:protein interactions and the pairing of boundary elements in vivo Genes & Dev., March 1, 2003; 17(5): 664 - 675. [Abstract] [Full Text] [PDF]

				S.-M. Kim, D. D. Dubey, and J. A. Huberman Early-replicating heterochromatin Genes & Dev., February 1, 2003; 17(3): 330 - 335. [Abstract] [Full Text] [PDF]