Limits...
Meiotic telomere protein Ndj1p is required for meiosis-specific telomere distribution, bouquet formation and efficient homologue pairing.

Trelles-Sticken E, Dresser ME, Scherthan H - J. Cell Biol. (2000)

Bottom Line: Since ndj1Delta meiocytes fail to cluster their telomeres at any prophase stage, Ndj1p is the first protein shown to be required for bouquet formation in a synaptic organism.Analysis of homologue pairing by two-color fluorescence in situ hybridization with cosmid probes to regions on III, IX, and XI revealed that disruption of bouquet formation is associated with a significant delay (>2 h) of homologue pairing.Under naturally occurring conditions, bouquet formation may allow for rapid sporulation and confer a selective advantage.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Biology and Genetics, University of Kaiserslautern, D-67653 Kaiserslautern, Germany.

ABSTRACT
We have investigated the requirements for NDJ1 in meiotic telomere redistribution and clustering in synchronized cultures of Saccharomyces cerevisiae. On induction of wild-type meiosis, telomeres disperse from premeiotic aggregates over the nuclear periphery, and then cluster near the spindle pole body (bouquet arrangement) before dispersing again. In ndj1Delta meiocytes, telomeres are scattered throughout the nucleus and fail to form perinuclear meiosis-specific distribution patterns, suggesting that Ndj1p may function to tether meiotic telomeres to the nuclear periphery. Since ndj1Delta meiocytes fail to cluster their telomeres at any prophase stage, Ndj1p is the first protein shown to be required for bouquet formation in a synaptic organism. Analysis of homologue pairing by two-color fluorescence in situ hybridization with cosmid probes to regions on III, IX, and XI revealed that disruption of bouquet formation is associated with a significant delay (>2 h) of homologue pairing. An increased and persistent fraction of ndj1Delta meiocytes with Zip1p polycomplexes suggests that chromosome polarization is important for synapsis progression. Thus, our observations support the hypothesis that meiotic telomere clustering contributes to efficient homologue alignment and synaptic pairing. Under naturally occurring conditions, bouquet formation may allow for rapid sporulation and confer a selective advantage.

Show MeSH

Related in: MedlinePlus

Spatial analysis of Rap1p telomere signal distribution with respect to the nearest nuclear boundary segment. The frequency (%) of occurrence of Rap1/FITC signal centers situated at particular distances (given in 0.2-μm intervals) from the nearest nuclear periphery segment as determined at the equatorial plane from the corresponding confocal DAPI images. The values were derived from 146 signal spots for ndj1Δ (ndj1), and 86 for wild type (WT). In the wild type, most signal spot centers locate in the immediate vicinity of the nuclear periphery (open bars). An altered spatial distribution of telomeric Rap1 signals in ndj1Δ nuclei is reflected by a higher portion of telomeric signals being more distant from the nuclear border (solid bars).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2189801&req=5

Figure 7: Spatial analysis of Rap1p telomere signal distribution with respect to the nearest nuclear boundary segment. The frequency (%) of occurrence of Rap1/FITC signal centers situated at particular distances (given in 0.2-μm intervals) from the nearest nuclear periphery segment as determined at the equatorial plane from the corresponding confocal DAPI images. The values were derived from 146 signal spots for ndj1Δ (ndj1), and 86 for wild type (WT). In the wild type, most signal spot centers locate in the immediate vicinity of the nuclear periphery (open bars). An altered spatial distribution of telomeric Rap1 signals in ndj1Δ nuclei is reflected by a higher portion of telomeric signals being more distant from the nuclear border (solid bars).

Mentions: The relation of the Rap1p telomere signals to the nuclear periphery was determined in the light optical section of the equator of each nucleus. The distance from Rap1/FITC signal centers to the nearest nuclear boundary of the DAPI image was calculated by a dedicated program. This two-dimensional procedure accounts for the small dimensions of the yeast nucleus and its irregular shape at meiosis (see Zickler and Olson 1975), which precludes applying a distribution analysis of signal spots from a geometrically defined center. The data obtained are displayed in a bar graph according to frequency of signals at distance units of multiples of 0.2 μm from the nearest nuclear boundary segment (Fig. 7). In wild-type cells, the vast majority of telomeric spots were found near the nuclear periphery (Fig. 6 and Fig. 7). A deviation from this peripheral telomeric Rap1p distribution in wild-type meiocyte nuclei was apparent in ndj1Δ nuclei. In the latter, a significant fraction of signals (97.5% level by G test) located remote from the nuclear boundary (i.e., 34% of signal spots were located 0.6–1 μm from the nearest nuclear edge), while in the wild type only 18% of spots were found in this more internal nuclear compartment (Fig. 7). These results suggest that the perinuclear localization of meiotic telomeres is disrupted in ndj1Δ meiosis.


Meiotic telomere protein Ndj1p is required for meiosis-specific telomere distribution, bouquet formation and efficient homologue pairing.

Trelles-Sticken E, Dresser ME, Scherthan H - J. Cell Biol. (2000)

Spatial analysis of Rap1p telomere signal distribution with respect to the nearest nuclear boundary segment. The frequency (%) of occurrence of Rap1/FITC signal centers situated at particular distances (given in 0.2-μm intervals) from the nearest nuclear periphery segment as determined at the equatorial plane from the corresponding confocal DAPI images. The values were derived from 146 signal spots for ndj1Δ (ndj1), and 86 for wild type (WT). In the wild type, most signal spot centers locate in the immediate vicinity of the nuclear periphery (open bars). An altered spatial distribution of telomeric Rap1 signals in ndj1Δ nuclei is reflected by a higher portion of telomeric signals being more distant from the nuclear border (solid bars).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2189801&req=5

Figure 7: Spatial analysis of Rap1p telomere signal distribution with respect to the nearest nuclear boundary segment. The frequency (%) of occurrence of Rap1/FITC signal centers situated at particular distances (given in 0.2-μm intervals) from the nearest nuclear periphery segment as determined at the equatorial plane from the corresponding confocal DAPI images. The values were derived from 146 signal spots for ndj1Δ (ndj1), and 86 for wild type (WT). In the wild type, most signal spot centers locate in the immediate vicinity of the nuclear periphery (open bars). An altered spatial distribution of telomeric Rap1 signals in ndj1Δ nuclei is reflected by a higher portion of telomeric signals being more distant from the nuclear border (solid bars).
Mentions: The relation of the Rap1p telomere signals to the nuclear periphery was determined in the light optical section of the equator of each nucleus. The distance from Rap1/FITC signal centers to the nearest nuclear boundary of the DAPI image was calculated by a dedicated program. This two-dimensional procedure accounts for the small dimensions of the yeast nucleus and its irregular shape at meiosis (see Zickler and Olson 1975), which precludes applying a distribution analysis of signal spots from a geometrically defined center. The data obtained are displayed in a bar graph according to frequency of signals at distance units of multiples of 0.2 μm from the nearest nuclear boundary segment (Fig. 7). In wild-type cells, the vast majority of telomeric spots were found near the nuclear periphery (Fig. 6 and Fig. 7). A deviation from this peripheral telomeric Rap1p distribution in wild-type meiocyte nuclei was apparent in ndj1Δ nuclei. In the latter, a significant fraction of signals (97.5% level by G test) located remote from the nuclear boundary (i.e., 34% of signal spots were located 0.6–1 μm from the nearest nuclear edge), while in the wild type only 18% of spots were found in this more internal nuclear compartment (Fig. 7). These results suggest that the perinuclear localization of meiotic telomeres is disrupted in ndj1Δ meiosis.

Bottom Line: Since ndj1Delta meiocytes fail to cluster their telomeres at any prophase stage, Ndj1p is the first protein shown to be required for bouquet formation in a synaptic organism.Analysis of homologue pairing by two-color fluorescence in situ hybridization with cosmid probes to regions on III, IX, and XI revealed that disruption of bouquet formation is associated with a significant delay (>2 h) of homologue pairing.Under naturally occurring conditions, bouquet formation may allow for rapid sporulation and confer a selective advantage.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Biology and Genetics, University of Kaiserslautern, D-67653 Kaiserslautern, Germany.

ABSTRACT
We have investigated the requirements for NDJ1 in meiotic telomere redistribution and clustering in synchronized cultures of Saccharomyces cerevisiae. On induction of wild-type meiosis, telomeres disperse from premeiotic aggregates over the nuclear periphery, and then cluster near the spindle pole body (bouquet arrangement) before dispersing again. In ndj1Delta meiocytes, telomeres are scattered throughout the nucleus and fail to form perinuclear meiosis-specific distribution patterns, suggesting that Ndj1p may function to tether meiotic telomeres to the nuclear periphery. Since ndj1Delta meiocytes fail to cluster their telomeres at any prophase stage, Ndj1p is the first protein shown to be required for bouquet formation in a synaptic organism. Analysis of homologue pairing by two-color fluorescence in situ hybridization with cosmid probes to regions on III, IX, and XI revealed that disruption of bouquet formation is associated with a significant delay (>2 h) of homologue pairing. An increased and persistent fraction of ndj1Delta meiocytes with Zip1p polycomplexes suggests that chromosome polarization is important for synapsis progression. Thus, our observations support the hypothesis that meiotic telomere clustering contributes to efficient homologue alignment and synaptic pairing. Under naturally occurring conditions, bouquet formation may allow for rapid sporulation and confer a selective advantage.

Show MeSH
Related in: MedlinePlus