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Genetics. 2014 Nov;198(3):983-93. doi: 10.1534/genetics.114.169698. Epub 2014 Sep 11.

Msh4 and Msh5 function in SC-independent chiasma formation during the streamlined meiosis of Tetrahymena.

Author information

1
Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria.
2
Research Institute of Molecular Pathology, A-130 Vienna, Austria IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, A-1030 Vienna, Austria.
3
Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria josef.loidl@univie.ac.at.

Abstract

ZMM proteins have been defined in budding yeast as factors that are collectively involved in the formation of interfering crossovers (COs) and synaptonemal complexes (SCs), and they are a hallmark of the predominant meiotic recombination pathway of most organisms. In addition to this so-called class I CO pathway, a minority of crossovers are formed by a class II pathway, which involves the Mus81-Mms4 endonuclease complex. This is the only CO pathway in the SC-less meiosis of the fission yeast. ZMM proteins (including SC components) were always found to be co-occurring and hence have been regarded as functionally linked. Like the fission yeast, the protist Tetrahymena thermophila does not possess a SC, and its COs are dependent on Mus81-Mms4. Here we show that the ZMM proteins Msh4 and Msh5 are required for normal chiasma formation, and we propose that they have a pro-CO function outside a canonical class I pathway in Tetrahymena. Thus, the two-pathway model is not tenable as a general rule.

KEYWORDS:

DSB repair; crossover pathways; meiosis; recombination; synaptonemal complex

PMID:
25217051
PMCID:
PMC4224184
DOI:
10.1534/genetics.114.169698
[Indexed for MEDLINE]
Free PMC Article

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