TY - JOUR
T1 - Altered distribution of MLH1 foci is associated with changes in cohesins and chromosome axis compaction in an asynaptic mutant of tomato
AU - Qiao, Huanyu
AU - Offenberg, Hildo H.
AU - Anderson, Lorinda K.
N1 - Funding Information:
Acknowledgements We thank Christa Heyting (U. Wageningen, Netherlands) for providing antibodies and plasmids and for useful comments on the manuscript. We also thank Chris Makaroff (U. Miami, Ohio) and Christine Mezard (INRA, Versailles, France) for their gifts of antibodies to AtSYN1 and AtSCC3, respectively. This work was supported by National Science Foundation grants (MCB-314644 and MCB-1019708) to LKA.
PY - 2012/6
Y1 - 2012/6
N2 - In most multicellular eukaryotes, synapsis [synaptonemal complex (SC) formation] between pairs of homologous chromosomes during prophase I of meiosis is closely linked with crossing over. Asynaptic mutants in plants have reduced synapsis and increased univalent frequency, often resulting in genetically unbalanced gametes and reduced fertility. Surprisingly, some asynaptic mutants (like as1 in tomato) have wildtype or increased levels of crossing over. To investigate, we examined SC spreads from as1/as1 microsporocytes using both light and electron microscopic immunolocalization. We observed increased numbers of MLH1 foci (a crossover marker) per unit length of SC in as1 mutants compared to wild-type. These changes are associated with reduced levels of detectable cohesin proteins in the axial and lateral elements (AE/LEs) of SCs, and the AE/LEs of as1 mutants are also significantly longer than those of wild-type or another asynaptic mutant. These results indicate that chromosome axis structure, synapsis, and crossover control are all closely linked in plants.
AB - In most multicellular eukaryotes, synapsis [synaptonemal complex (SC) formation] between pairs of homologous chromosomes during prophase I of meiosis is closely linked with crossing over. Asynaptic mutants in plants have reduced synapsis and increased univalent frequency, often resulting in genetically unbalanced gametes and reduced fertility. Surprisingly, some asynaptic mutants (like as1 in tomato) have wildtype or increased levels of crossing over. To investigate, we examined SC spreads from as1/as1 microsporocytes using both light and electron microscopic immunolocalization. We observed increased numbers of MLH1 foci (a crossover marker) per unit length of SC in as1 mutants compared to wild-type. These changes are associated with reduced levels of detectable cohesin proteins in the axial and lateral elements (AE/LEs) of SCs, and the AE/LEs of as1 mutants are also significantly longer than those of wild-type or another asynaptic mutant. These results indicate that chromosome axis structure, synapsis, and crossover control are all closely linked in plants.
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U2 - 10.1007/s00412-012-0363-z
DO - 10.1007/s00412-012-0363-z
M3 - Article
C2 - 22350750
AN - SCOPUS:84864870273
SN - 0009-5915
VL - 121
SP - 291
EP - 305
JO - Chromosoma
JF - Chromosoma
IS - 3
ER -