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Telomere-independent homologue pairing and checkpoint escape of accessory ring chromosomes in male mouse meiosis.

Voet T, Liebe B, Labaere C, Marynen P, Scherthan H - J. Cell Biol. (2003)

Bottom Line: Fluorescent in situ hybridization and three-dimensional fluorescence microscopy revealed that ring MCs did not participate in meiotic telomere clustering while MC homologues paired at the XY-body periphery.Unaligned MCs triggered the spindle checkpoint leading to apoptosis of metaphase cells.Our findings indicate a telomere-independent mechanism for pairing of mammalian MCs, illuminate escape routes to meiotic checkpoints, and give clues for genetic engineering of germ line-permissive chromosomal vectors.

View Article: PubMed Central - PubMed

Affiliation: Human Genome Laboratory, Department of Human Genetics, Flanders Interuniversity Institute for Biotechnology, University of Leuven, Belgium.

ABSTRACT
We analyzed transmission of a ring minichromosome (MC) through mouse spermatogenesis as a monosome and in the presence of a homologue. Mice, either monosomic or disomic for the MC, produced MC+ offspring. In the monosomic condition, most univalents underwent self-synapsis as indicated by STAG3, SCP3, and SCP1 deposition. Fluorescent in situ hybridization and three-dimensional fluorescence microscopy revealed that ring MCs did not participate in meiotic telomere clustering while MC homologues paired at the XY-body periphery. Self-synapsis of MC(s) and association with the XY-body likely allowed them to pass putative pachytene checkpoints. At metaphase I and II, MC kinetochores assembled MAD2 and BUBR1 spindle checkpoint proteins. Unaligned MCs triggered the spindle checkpoint leading to apoptosis of metaphase cells. Other MCs frequently associated with mouse pericentric heterochromatin, which may have allowed them to pass the spindle checkpoint. Our findings indicate a telomere-independent mechanism for pairing of mammalian MCs, illuminate escape routes to meiotic checkpoints, and give clues for genetic engineering of germ line-permissive chromosomal vectors.

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MC centromeres and segregation. (A) MC-specific α-satellite DNA FISH (red) on sperm of a disomic mouse. Spermheads with 1–3 MC signals are detected. (B) Testes to body weight ratios (mg/g) of wild-type (n = 13), monosomic (n = 11), and disomic (n = 7) mice. (C and D) IF staining for CREST (green) combined with α-satellite MC FISH (red) on metaphase I (C) and II (D) nuclei. (E and F) CENP-C IF staining signals detected at the FISH-labeled CV in prometaphase I (E) and II (F) nuclei. Arrowheads in C–F denote MC FISH signals and their respective kinetochore signals. (Eiii and Fiii) Inverted grayscale DAPI channel.
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fig1: MC centromeres and segregation. (A) MC-specific α-satellite DNA FISH (red) on sperm of a disomic mouse. Spermheads with 1–3 MC signals are detected. (B) Testes to body weight ratios (mg/g) of wild-type (n = 13), monosomic (n = 11), and disomic (n = 7) mice. (C and D) IF staining for CREST (green) combined with α-satellite MC FISH (red) on metaphase I (C) and II (D) nuclei. (E and F) CENP-C IF staining signals detected at the FISH-labeled CV in prometaphase I (E) and II (F) nuclei. Arrowheads in C–F denote MC FISH signals and their respective kinetochore signals. (Eiii and Fiii) Inverted grayscale DAPI channel.

Mentions: All monosomic and disomic MC+ mice of both sexes tested so far produced live MC+ offspring when mated to wild-type mice. Additionally, meiotic MC missegregation occurred in disomic mice of both sexes because part of their offspring harbored two MCs when mated to wild-type mice (Table II) and because 8–37% of their sperm nuclei (n ≥ 100/animal) contained two or more MCs (Table III Fig. 1 A). However, the MC-carrying males displayed similar testes weights (ANOVA combined with post-hoc test; P values > 0.16; Fig. 1 B).


Telomere-independent homologue pairing and checkpoint escape of accessory ring chromosomes in male mouse meiosis.

Voet T, Liebe B, Labaere C, Marynen P, Scherthan H - J. Cell Biol. (2003)

MC centromeres and segregation. (A) MC-specific α-satellite DNA FISH (red) on sperm of a disomic mouse. Spermheads with 1–3 MC signals are detected. (B) Testes to body weight ratios (mg/g) of wild-type (n = 13), monosomic (n = 11), and disomic (n = 7) mice. (C and D) IF staining for CREST (green) combined with α-satellite MC FISH (red) on metaphase I (C) and II (D) nuclei. (E and F) CENP-C IF staining signals detected at the FISH-labeled CV in prometaphase I (E) and II (F) nuclei. Arrowheads in C–F denote MC FISH signals and their respective kinetochore signals. (Eiii and Fiii) Inverted grayscale DAPI channel.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2172825&req=5

fig1: MC centromeres and segregation. (A) MC-specific α-satellite DNA FISH (red) on sperm of a disomic mouse. Spermheads with 1–3 MC signals are detected. (B) Testes to body weight ratios (mg/g) of wild-type (n = 13), monosomic (n = 11), and disomic (n = 7) mice. (C and D) IF staining for CREST (green) combined with α-satellite MC FISH (red) on metaphase I (C) and II (D) nuclei. (E and F) CENP-C IF staining signals detected at the FISH-labeled CV in prometaphase I (E) and II (F) nuclei. Arrowheads in C–F denote MC FISH signals and their respective kinetochore signals. (Eiii and Fiii) Inverted grayscale DAPI channel.
Mentions: All monosomic and disomic MC+ mice of both sexes tested so far produced live MC+ offspring when mated to wild-type mice. Additionally, meiotic MC missegregation occurred in disomic mice of both sexes because part of their offspring harbored two MCs when mated to wild-type mice (Table II) and because 8–37% of their sperm nuclei (n ≥ 100/animal) contained two or more MCs (Table III Fig. 1 A). However, the MC-carrying males displayed similar testes weights (ANOVA combined with post-hoc test; P values > 0.16; Fig. 1 B).

Bottom Line: Fluorescent in situ hybridization and three-dimensional fluorescence microscopy revealed that ring MCs did not participate in meiotic telomere clustering while MC homologues paired at the XY-body periphery.Unaligned MCs triggered the spindle checkpoint leading to apoptosis of metaphase cells.Our findings indicate a telomere-independent mechanism for pairing of mammalian MCs, illuminate escape routes to meiotic checkpoints, and give clues for genetic engineering of germ line-permissive chromosomal vectors.

View Article: PubMed Central - PubMed

Affiliation: Human Genome Laboratory, Department of Human Genetics, Flanders Interuniversity Institute for Biotechnology, University of Leuven, Belgium.

ABSTRACT
We analyzed transmission of a ring minichromosome (MC) through mouse spermatogenesis as a monosome and in the presence of a homologue. Mice, either monosomic or disomic for the MC, produced MC+ offspring. In the monosomic condition, most univalents underwent self-synapsis as indicated by STAG3, SCP3, and SCP1 deposition. Fluorescent in situ hybridization and three-dimensional fluorescence microscopy revealed that ring MCs did not participate in meiotic telomere clustering while MC homologues paired at the XY-body periphery. Self-synapsis of MC(s) and association with the XY-body likely allowed them to pass putative pachytene checkpoints. At metaphase I and II, MC kinetochores assembled MAD2 and BUBR1 spindle checkpoint proteins. Unaligned MCs triggered the spindle checkpoint leading to apoptosis of metaphase cells. Other MCs frequently associated with mouse pericentric heterochromatin, which may have allowed them to pass the spindle checkpoint. Our findings indicate a telomere-independent mechanism for pairing of mammalian MCs, illuminate escape routes to meiotic checkpoints, and give clues for genetic engineering of germ line-permissive chromosomal vectors.

Show MeSH
Related in: MedlinePlus