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Abstract BackgroundMeiosis is a specialized cell division that underpins sexual reproduction in most eukaryotes. During meiosis, interhomolog meiotic recombination facilitates accurate chromosome segregation and generates genetic diversity by shuffling parental alleles in the gametes. The frequency of meiotic recombination inArabidopsishas a U-shaped curve in response to environmental temperature, and is dependent on the Type I, crossover (CO) interference-sensitive pathway. The mechanisms that modulate recombination frequency in response to temperature are not yet known. ResultsIn this study, we compare the transcriptomes of thermally-stressed meiotic-stage anthers frommsh4andmus81mutants that mediate the Type I and Type II meiotic recombination pathways, respectively. We show that heat stress reduces the number of expressed genes regardless of genotype. In addition,msh4mutants have a distinct gene expression pattern compared tomus81and wild type controls. Interestingly,ASY1,which encodes a HORMA domain protein that is a component of meiotic chromosome axes, is up-regulated in wild type andmus81but not inmsh4. In addition,SDSthe meiosis-specific cyclin-like gene,DMC1the meiosis-specific recombinase,SYN1/REC8the meiosis-specific cohesion complex component, andSWI1which functions in meiotic sister chromatid cohesion are up-regulated in all three genotypes. We also characterize 51 novel, previously unannotated transcripts, and show that their promoter regions are associated with A-rich meiotic recombination hotspot motifs. ConclusionsOur transcriptomic analysis ofmsh4andmus81mutants enhances our understanding of how the Type I and Type II meiotic CO pathway respond to environmental temperature stress and might provide a strategy to manipulate recombination levels in plants.
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The B-type cyclin Clb4 prevents meiosis I sister centromere separation in budding yeast
Abstract In meiosis, one round of DNA replication followed by two rounds of chromosome segregation halves the ploidy of the original cell. Accurate chromosome segregation in meiosis I depends on recombination between homologous chromosomes. Sister centromeres attach to the same spindle pole in this division and only segregate in meiosis II. We used budding yeast to select for mutations that produced viable spores in the absence of recombination. The most frequent mutations inactivated CLB4, which encodes one of four B-type cyclins. In two wild yeast isolates, Y55 and SK1, but not the W303 laboratory strain, deleting CLB4 causes premature sister centromere separation and segregation in meiosis I and frequent termination of meiosis after a single division, demonstrating a novel role for Clb4 in meiotic chromosome dynamics and meiotic progression. This role depends on the genetic background since meiosis in W303 is largely independent of CLB4.
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- Award ID(s):
- 2319006
- PAR ID:
- 10633746
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- G3: Genes, Genomes, Genetics
- Volume:
- 15
- Issue:
- 9
- ISSN:
- 2160-1836
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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