Unusual nuclear structures in meiotic prophase of fission yeast: a cytological analysis

Earlier results from sectioned nuclei indicating that Schizosaccharomyces pombe does not develop a classical tripartite synaptonemal complex (SC) during meiotic prophase are confirmed by spreading of whole nuclei. The linear elements appearing during prophase I resemble the axial cores (SC precursor...

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Bibliographic Details
Published in:The Journal of cell biology 1993-04, Vol.121 (2), p.241-256
Main Authors: Bahler, J. (University of Bern, Bern, Switzerland), Wyler, T, Loidl, J, Kohli, J
Format: Article
Language:English
Subjects:
APAREAMIENTO CROMOSOMICO
APPARIEMENT CHROMOSOMIQUE
Biological and medical sciences
Cell nucleus
Cell Nucleus - ultrastructure
Cells
Cellular biology
Centromeres
Chromatin
Chromatin. Chromosome
CHROMOSOME
Chromosomes
CITOLOGIA
CROMOSOMAS
Crossing Over, Genetic
Cytological Techniques
CYTOLOGIE
Deoxyribonucleic acid
Diploidy
DNA
ENDOMYCETALES
Fundamental and applied biological sciences. Psychology
Genes
Haploidy
MEIOSE
MEIOSIS
Models, Biological
Molecular and cellular biology
Molecular genetics
Prophase
RECOMBINACION
RECOMBINAISON
Schizosaccharomyces - cytology
Schizosaccharomyces - ultrastructure
Schizosaccharomyces pombe
Synaptonemal Complex
Yeasts
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Description
Summary:Earlier results from sectioned nuclei indicating that Schizosaccharomyces pombe does not develop a classical tripartite synaptonemal complex (SC) during meiotic prophase are confirmed by spreading of whole nuclei. The linear elements appearing during prophase I resemble the axial cores (SC precursors) of other organisms. The number of linear elements in haploid, diploid, and tetraploid strains is always higher than the chromosome number, implying that they are not formed continuously along the chromosomes. Time course experiments reveal that the elements appear after DNA replication and form networks and bundles. Later they separate and approximately 24 individual elements with a total length of 34 micrometers are observed before degradation and meiotic divisions. Parallel staining of DNA reveals changes in nuclear shape during meiotic prophase. Strains with a mei4 mutation are blocked at a late prophase stage. In serial sections we additionally observed a constant arrangement of the spindle pole body, the nucleolus, and the presumptive centromere cluster. Thus, S. pombe manages to recombine and segregate its chromosomes without SC. This might correlate with the absence of crossover interference. We propose a mechanism for chromosome pairing with initial recognition of the homologs at the centromeres and suggest functions of the linear elements in preparation of the chromosomes for meiosis I disjunction. With the spreading technique combined genetic, molecular, and cytological approaches become feasible in S. pombe. This provides an opportunity to study essential meiotic functions in the absence of SCs which may help to clarify the significance of the SC and its components for meiotic chromosome structure and function
ISSN:0021-9525
1540-8140
DOI:10.1083/jcb.121.2.241