Progression of meiotic recombination requires structural maturation of the central element of the synaptonemal complex.
The synaptonemal complex is an elaborate meiosis-specific supramolecular protein assembly that promotes chromosome synapsis and meiotic recombination. We inactivated the meiosis-specific gene Tex12 and found that TEX12 is essential for progression of meiosis in both male and female germ cells. Structural analysis of the synaptonemal complex in Tex12-/- meiocytes revealed a disrupted central element structure, a dense structure residing between the synapsed homologous chromosomes. Chromosome synapsis is initiated at multiple positions along the paired homologous chromosomes in Tex12-/- meiotic cells, but fails to propagate along the chromosomes. Furthermore, although meiotic recombination is initiated in Tex12-/- meiotic cells, these early recombination events do not develop into meiotic crossovers. Hence, the mere initiation of synapsis is not sufficient to support meiotic crossing-over. Our results show that TEX12 is a component of the central element structure of the synaptonemal complex required for propagation of synapsis along the paired homologous chromosomes and maturation of early recombination events into crossovers.
Hamer
Geert
G
Department of Cell and Molecular Biology, Karolinska Institute, Berzelius väg 35, Stockholm, Sweden.
Wang
Hong
H
Bolcun-Filas
Ewelina
E
Cooke
Howard J
HJ
Benavente
Ricardo
R
Höög
Christer
C
D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D003434:Crossing Over, Genetic; D053903:DNA Breaks, Double-Stranded; D007150:Immunohistochemistry; D008540:Meiosis / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D011995:Recombination, Genetic; D013573:Synaptonemal Complex / Q000378:metabolism / Q000648:ultrastructure*
D002868:Chromosomal Proteins, Non-Histone; C515820:TEX12 protein, mouse