DNA double-strand breaks, recombination and synapsis: the timing of meiosis differs in grasshoppers and flies.
The temporal and functional relationships between DNA events of meiotic recombination and synaptonemal complex formation are a matter of discussion within the meiotic field. To analyse this subject in grasshoppers, organisms that have been considered as models for meiotic studies for many years, we have studied the localization of phosphorylated histone H2AX (gamma-H2AX), which marks the sites of double-strand breaks (DSBs), in combination with localization of cohesin SMC3 and recombinase Rad51. We show that the loss of gamma-H2AX staining is spatially and temporally linked to synapsis, and that in grasshoppers the initiation of recombination, produced as a consequence of DSB formation, precedes synapsis. This result supports the idea that grasshoppers display a pairing pathway that is not present in other insects such as Drosophila melanogaster, but is similar to those reported in yeast, mouse and Arabidopsis. In addition, we have observed the presence of gamma-H2AX in the X chromosome from zygotene to late pachytene, indicating that the function of H2AX phosphorylation during grasshopper spermatogenesis is not restricted to the formation of gamma-H2AX foci at DNA DSBs.
Viera
Alberto
A
Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Santos
Juan L
JL
Page
Jesús
J
Parra
M Teresa
MT
Calvente
Adela
A
Cifuentes
Marta
M
Gómez
Rocío
R
Lira
Renee
R
Suja
José A
JA
Rufas
Julio S
JS
D000818:Animals; D023902:Chromosome Pairing / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004175:Diptera / Q000235:genetics* / Q000502:physiology; D005455:Fluorescent Antibody Technique; D006110:Grasshoppers / Q000235:genetics* / Q000502:physiology; D006657:Histones / Q000378:metabolism; D015151:Immunoblotting; D008297:Male; D008540:Meiosis / Q000502:physiology*; D051135:Rad51 Recombinase; D011995:Recombination, Genetic / Q000502:physiology*; D013090:Spermatocytes / Q000166:cytology
D004268:DNA-Binding Proteins; D006657:Histones; D051135:Rad51 Recombinase