The effect of the wheat Ph1 locus on chromatin organisation and meiotic chromosome pairing analysed by genome painting

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• 作者：Elena I. Mikhailova ; Tomás Naranjo ; Ken Shepherd ; Jannie Wennekes-van Eden ; Christa Heyting and J. Hans de Jong
• 刊名：Chromosoma
• 出版年：1998
• 出版时间：November 1998
• 年：1998
• 卷：107
• 期：5
• 页码：339-350
• 全文大小：361 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Cell Biology
  Developmental Biology
  Biochemistry
  Human Genetics
  Animal Genetics and Genomics
  Eukaryotic Microbiology
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-0886

文摘

The Ph1 locus in wheat influences homo(eo)logous chromosome pairing. We have analysed its effect on the behaviour and morphology of two 5RL rye telosomes in a wheat background, by genomic in situ hybridisation (GISH), using rye genomic DNA as a probe. Our main objective was to study the effect of different alleles of the Ph1 locus on the morphology and behaviour of the rye telosomes in interphase nuclei of tapetal cells and in pollen mother cells at early stages of meiosis. The telosomes, easily detectable at all stages, showed a brightly fluorescing chromomere in the distal region and a constriction in the proximal part. These diagnostic markers enabled us to define the centromere and telomere regions of the rye telosomes. In the presence of functional copies of Ph1, the rye telosomes associated at pre-leptotene, disjoined and reorganised their shape at leptotene, and became fully homologously paired at zygotene – pachytene. In plants without functional alleles (ph1bph1b), the rye telosomes displayed an aberrant morphology, their premeiotic associations were clearly disturbed and their pairing during zygotene and pachytene was reduced and irregular. The Ph1 locus also influenced the behaviour of rye telosomes in the interphase nuclei of tapetal cells: in Ph1Ph1 plants, the rye telosomes occupied distinct, parallel-oriented domains, whereas in tapetal nuclei of ph1bph1b plants they were intermingled with wheat chromosomes and showed a heavily distorted morphology. The results shed new light on the effect of Ph1, and suggest that this locus is involved in chromosome condensation and/or scaffold organisation. Our explanation might account for various apparently contradictory and pleiotropic effects of this locus on both premeiotic associations of homologues, the regulation of meiotic homo(eo)logous chromosome pairing and synapsis, the resolution of bivalent interlockings and centromere behaviour.