Cohesin axis maturation and presence of RAD51 during first meiotic prophase in a true bug.
We have analyzed in a true bug, Graphosoma italicum (Pentatomidae, Hemiptera), the temporal and functional relationships between recombination events, synapsis progression, and SMC1alpha and SMC3 cohesin axis maturation throughout the male first meiotic prophase. The localization of the histone variant histone H3 trimethylated at lysine 9 at chromosome ends has allowed us to determine the association of these heterochromatic domains through prophase I stages. Results highlighted that cohesins provide to be good markers for synapsis progression since the formation, morphology, and development of the SMC1alpha and SMC3 cohesin axes resemble the synaptonemal complex dynamics and, also, that in this species the initiation of recombination precedes synapsis. In addition, we have carried out an accurate cytological characterization of the diffuse stage, which takes place after pachytene, and also analyzed the presence of the cohesin subunits, SMC1alpha and SMC3, and the recombinase RAD51 at this stage. The mechanisms underlying the absence of SMC1alpha and SMC3 axes from the diffuse stage onwards are discussed.
Viera
Alberto
A
Departamento de Biología, Edificio de Biológicas, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Santos
Juan Luis
JL
Parra
María Teresa
MT
Calvente
Adela
A
Gómez
Rocío
R
de la Fuente
Roberto
R
Suja
José Angel
JA
Page
Jesús
J
Rufas
Julio S
JS
D000818:Animals; D018797:Cell Cycle Proteins / Q000502:physiology*; D002868:Chromosomal Proteins, Non-Histone / Q000502:physiology*; D002875:Chromosomes / Q000648:ultrastructure; D006430:Hemiptera; D006657:Histones / Q000378:metabolism; D008297:Male; D049469:Meiotic Prophase I / Q000502:physiology*; D051135:Rad51 Recombinase / Q000235:genetics / Q000502:physiology*; D011995:Recombination, Genetic / Q000502:physiology; D013090:Spermatocytes / Q000378:metabolism; D013573:Synaptonemal Complex / Q000502:physiology; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D051135:Rad51 Recombinase; D000097722:Cohesins