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Highly condensed chromatins are formed adjacent to subtelomeric and decondensed silent chromatin in fission yeast.

Matsuda A, Chikashige Y, Ding DQ, Ohtsuki C, Mori C, Asakawa H, Kimura H, Haraguchi T, Hiraoka Y - Nat Commun (2015)

Bottom Line: Knob regions span ∼50 kb of sequence devoid of methylated histones.Disruption of methylation at lysine 36 of histone H3 (H3K36) eliminates knob formation and gene repression at the subtelomeric and adjacent knob regions.Thus, epigenetic marks at H3K36 play crucial roles in the formation of a unique chromatin structure and in gene regulation at those regions in S. pombe.

View Article: PubMed Central - PubMed

Affiliation: 1] Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2, Iwaoka, Iwaoka-cho, Kobe 651-2492, Japan [2] Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan.

ABSTRACT
It is generally believed that silent chromatin is condensed and transcriptionally active chromatin is decondensed. However, little is known about the relationship between the condensation levels and gene expression. Here we report the condensation levels of interphase chromatin in the fission yeast Schizosaccharomyces pombe examined by super-resolution fluorescence microscopy. Unexpectedly, silent chromatin is less condensed than the euchromatin. Furthermore, the telomeric silent regions are flanked by highly condensed chromatin bodies, or 'knobs'. Knob regions span ∼50 kb of sequence devoid of methylated histones. Knob condensation is independent of HP1 homologue Swi6 and other gene silencing factors. Disruption of methylation at lysine 36 of histone H3 (H3K36) eliminates knob formation and gene repression at the subtelomeric and adjacent knob regions. Thus, epigenetic marks at H3K36 play crucial roles in the formation of a unique chromatin structure and in gene regulation at those regions in S. pombe.

No MeSH data available.


Related in: MedlinePlus

Appearance of chromatin in the interphase nucleus of S. pombe.Chromatin structure in the interphase nucleus of S. pombe expressing H2B-GFP observed using 3DSIM. Single optical sections are shown. Raw (wide field), deconvolution and 3DSIM images of a single nucleus of a live cell are shown, together with a single 3DSIM image of another fixed cell. The contrast of the images is adjusted to show the background with a very low noise level. Fixed cells showed chromatin structures similar to the live cells. Scale bar, 500 nm.
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f1: Appearance of chromatin in the interphase nucleus of S. pombe.Chromatin structure in the interphase nucleus of S. pombe expressing H2B-GFP observed using 3DSIM. Single optical sections are shown. Raw (wide field), deconvolution and 3DSIM images of a single nucleus of a live cell are shown, together with a single 3DSIM image of another fixed cell. The contrast of the images is adjusted to show the background with a very low noise level. Fixed cells showed chromatin structures similar to the live cells. Scale bar, 500 nm.

Mentions: Interphase nuclei in living S. pombe cells have almost uniform chromatin concentration levels when observed with conventional wide-field microscopy or deconvolution (Fig. 1). However, when observed with live 3DSIM, heterogeneous chromatin condensation levels were observed (Fig. 1; also see Supplementary Fig. 1 for the experimental background). We were able to reproduce this chromatin organization after chemical fixation (Fig. 1).


Highly condensed chromatins are formed adjacent to subtelomeric and decondensed silent chromatin in fission yeast.

Matsuda A, Chikashige Y, Ding DQ, Ohtsuki C, Mori C, Asakawa H, Kimura H, Haraguchi T, Hiraoka Y - Nat Commun (2015)

Appearance of chromatin in the interphase nucleus of S. pombe.Chromatin structure in the interphase nucleus of S. pombe expressing H2B-GFP observed using 3DSIM. Single optical sections are shown. Raw (wide field), deconvolution and 3DSIM images of a single nucleus of a live cell are shown, together with a single 3DSIM image of another fixed cell. The contrast of the images is adjusted to show the background with a very low noise level. Fixed cells showed chromatin structures similar to the live cells. Scale bar, 500 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525289&req=5

f1: Appearance of chromatin in the interphase nucleus of S. pombe.Chromatin structure in the interphase nucleus of S. pombe expressing H2B-GFP observed using 3DSIM. Single optical sections are shown. Raw (wide field), deconvolution and 3DSIM images of a single nucleus of a live cell are shown, together with a single 3DSIM image of another fixed cell. The contrast of the images is adjusted to show the background with a very low noise level. Fixed cells showed chromatin structures similar to the live cells. Scale bar, 500 nm.
Mentions: Interphase nuclei in living S. pombe cells have almost uniform chromatin concentration levels when observed with conventional wide-field microscopy or deconvolution (Fig. 1). However, when observed with live 3DSIM, heterogeneous chromatin condensation levels were observed (Fig. 1; also see Supplementary Fig. 1 for the experimental background). We were able to reproduce this chromatin organization after chemical fixation (Fig. 1).

Bottom Line: Knob regions span ∼50 kb of sequence devoid of methylated histones.Disruption of methylation at lysine 36 of histone H3 (H3K36) eliminates knob formation and gene repression at the subtelomeric and adjacent knob regions.Thus, epigenetic marks at H3K36 play crucial roles in the formation of a unique chromatin structure and in gene regulation at those regions in S. pombe.

View Article: PubMed Central - PubMed

Affiliation: 1] Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2, Iwaoka, Iwaoka-cho, Kobe 651-2492, Japan [2] Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita 565-0871, Japan.

ABSTRACT
It is generally believed that silent chromatin is condensed and transcriptionally active chromatin is decondensed. However, little is known about the relationship between the condensation levels and gene expression. Here we report the condensation levels of interphase chromatin in the fission yeast Schizosaccharomyces pombe examined by super-resolution fluorescence microscopy. Unexpectedly, silent chromatin is less condensed than the euchromatin. Furthermore, the telomeric silent regions are flanked by highly condensed chromatin bodies, or 'knobs'. Knob regions span ∼50 kb of sequence devoid of methylated histones. Knob condensation is independent of HP1 homologue Swi6 and other gene silencing factors. Disruption of methylation at lysine 36 of histone H3 (H3K36) eliminates knob formation and gene repression at the subtelomeric and adjacent knob regions. Thus, epigenetic marks at H3K36 play crucial roles in the formation of a unique chromatin structure and in gene regulation at those regions in S. pombe.

No MeSH data available.


Related in: MedlinePlus