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Chromatin associations in Arabidopsis interphase nuclei.

Schubert V, Rudnik R, Schubert I - Front Genet (2014)

Bottom Line: We found that chromatin fiber movement and variable associations, although in general relatively seldom, may occur between euchromatin segments along chromosomes, sometimes even over large distances.The combination of euchromatin segments bearing high or low co-expressing genes did not reveal different association frequencies probably due to adjacent genes of deviating expression patterns.Based on previous data and on FISH analyses presented here, we conclude that the global interphase chromatin organization in A. thaliana is relatively stable, due to the location of its 10 centromeres at the nuclear periphery and of the telomeres mainly at the centrally localized nucleolus.

View Article: PubMed Central - PubMed

Affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben Stadt Seeland, Germany.

ABSTRACT
The arrangement of chromatin within interphase nuclei seems to be caused by topological constraints and related to gene expression depending on tissue and developmental stage. In yeast and animals it was found that homologous and heterologous chromatin association are required to realize faithful expression and DNA repair. To test whether such associations are present in plants we analyzed Arabidopsis thaliana interphase nuclei by FISH using probes from different chromosomes. We found that chromatin fiber movement and variable associations, although in general relatively seldom, may occur between euchromatin segments along chromosomes, sometimes even over large distances. The combination of euchromatin segments bearing high or low co-expressing genes did not reveal different association frequencies probably due to adjacent genes of deviating expression patterns. Based on previous data and on FISH analyses presented here, we conclude that the global interphase chromatin organization in A. thaliana is relatively stable, due to the location of its 10 centromeres at the nuclear periphery and of the telomeres mainly at the centrally localized nucleolus. Nevertheless, chromatin movement enables a flexible spatial genome arrangement in plant nuclei.

No MeSH data available.


Related in: MedlinePlus

Configurations of adjacent euchromatin segments. (A) Scheme of chromosomes 1 and 3 showing the subtelomeric and interstitial position of adjacent segments (probed by two BACs in different colors). The percentage of nuclei where the adjacent segments were found not close together in 2C and 4C leaf and root nuclei, respectively, is indicated (number of investigated homologs (2C) and of sister chromatids (4C) in parentheses). (B) The top 2C and 4C nuclei show the T25K16 and F6F3 segments, as expected, close together. In the nuclei below, the homologous segments may also be completely (arrows) or partially associated (asterisks). In addition, due to chromatin fiber movement by elongation and/or sister chromatid separation, the adjacent segments may be localized distantly from each other. (C) Similar configurations as in (B). In particular segment F16M2 appears frequently elongated.
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Figure 4: Configurations of adjacent euchromatin segments. (A) Scheme of chromosomes 1 and 3 showing the subtelomeric and interstitial position of adjacent segments (probed by two BACs in different colors). The percentage of nuclei where the adjacent segments were found not close together in 2C and 4C leaf and root nuclei, respectively, is indicated (number of investigated homologs (2C) and of sister chromatids (4C) in parentheses). (B) The top 2C and 4C nuclei show the T25K16 and F6F3 segments, as expected, close together. In the nuclei below, the homologous segments may also be completely (arrows) or partially associated (asterisks). In addition, due to chromatin fiber movement by elongation and/or sister chromatid separation, the adjacent segments may be localized distantly from each other. (C) Similar configurations as in (B). In particular segment F16M2 appears frequently elongated.

Mentions: To test whether adjacent euchromatin segments along chromosome arms may loop out compared to each other, we tested 2C and 4C leaf and root nuclei with two overlapping BACs in different color by FISH. The frequency at which such pairs of BACs were not close together was relatively low along the chromosome arms (0–3.5%) in root and in leaf nuclei. However, at the subtelomeres of chromosome 1top and chromosome 3bottom arms the frequency of positional separation of the corresponding BAC pairs was clearly increased (up to 57.5% in 2C and 35.1% in 4C leaf nuclei) (Figure 4).


Chromatin associations in Arabidopsis interphase nuclei.

Schubert V, Rudnik R, Schubert I - Front Genet (2014)

Configurations of adjacent euchromatin segments. (A) Scheme of chromosomes 1 and 3 showing the subtelomeric and interstitial position of adjacent segments (probed by two BACs in different colors). The percentage of nuclei where the adjacent segments were found not close together in 2C and 4C leaf and root nuclei, respectively, is indicated (number of investigated homologs (2C) and of sister chromatids (4C) in parentheses). (B) The top 2C and 4C nuclei show the T25K16 and F6F3 segments, as expected, close together. In the nuclei below, the homologous segments may also be completely (arrows) or partially associated (asterisks). In addition, due to chromatin fiber movement by elongation and/or sister chromatid separation, the adjacent segments may be localized distantly from each other. (C) Similar configurations as in (B). In particular segment F16M2 appears frequently elongated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230181&req=5

Figure 4: Configurations of adjacent euchromatin segments. (A) Scheme of chromosomes 1 and 3 showing the subtelomeric and interstitial position of adjacent segments (probed by two BACs in different colors). The percentage of nuclei where the adjacent segments were found not close together in 2C and 4C leaf and root nuclei, respectively, is indicated (number of investigated homologs (2C) and of sister chromatids (4C) in parentheses). (B) The top 2C and 4C nuclei show the T25K16 and F6F3 segments, as expected, close together. In the nuclei below, the homologous segments may also be completely (arrows) or partially associated (asterisks). In addition, due to chromatin fiber movement by elongation and/or sister chromatid separation, the adjacent segments may be localized distantly from each other. (C) Similar configurations as in (B). In particular segment F16M2 appears frequently elongated.
Mentions: To test whether adjacent euchromatin segments along chromosome arms may loop out compared to each other, we tested 2C and 4C leaf and root nuclei with two overlapping BACs in different color by FISH. The frequency at which such pairs of BACs were not close together was relatively low along the chromosome arms (0–3.5%) in root and in leaf nuclei. However, at the subtelomeres of chromosome 1top and chromosome 3bottom arms the frequency of positional separation of the corresponding BAC pairs was clearly increased (up to 57.5% in 2C and 35.1% in 4C leaf nuclei) (Figure 4).

Bottom Line: We found that chromatin fiber movement and variable associations, although in general relatively seldom, may occur between euchromatin segments along chromosomes, sometimes even over large distances.The combination of euchromatin segments bearing high or low co-expressing genes did not reveal different association frequencies probably due to adjacent genes of deviating expression patterns.Based on previous data and on FISH analyses presented here, we conclude that the global interphase chromatin organization in A. thaliana is relatively stable, due to the location of its 10 centromeres at the nuclear periphery and of the telomeres mainly at the centrally localized nucleolus.

View Article: PubMed Central - PubMed

Affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben Stadt Seeland, Germany.

ABSTRACT
The arrangement of chromatin within interphase nuclei seems to be caused by topological constraints and related to gene expression depending on tissue and developmental stage. In yeast and animals it was found that homologous and heterologous chromatin association are required to realize faithful expression and DNA repair. To test whether such associations are present in plants we analyzed Arabidopsis thaliana interphase nuclei by FISH using probes from different chromosomes. We found that chromatin fiber movement and variable associations, although in general relatively seldom, may occur between euchromatin segments along chromosomes, sometimes even over large distances. The combination of euchromatin segments bearing high or low co-expressing genes did not reveal different association frequencies probably due to adjacent genes of deviating expression patterns. Based on previous data and on FISH analyses presented here, we conclude that the global interphase chromatin organization in A. thaliana is relatively stable, due to the location of its 10 centromeres at the nuclear periphery and of the telomeres mainly at the centrally localized nucleolus. Nevertheless, chromatin movement enables a flexible spatial genome arrangement in plant nuclei.

No MeSH data available.


Related in: MedlinePlus