INBIOMED   24026
INSTITUTO DE INVESTIGACIONES BIOMEDICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Structural Variations of the Unpaired Axesbfrom Sex Chromosomes in Different Mammalian Species
Autor/es:
FERNANDEZ MF; R. B. SCIURANO; DE LUCA GERALDINE; SOLARI A. J; RAHN I.M
Lugar:
Foz de Iguacu
Reunión:
Conferencia; 21st International Chromosome Conference (ICC); 2016
Resumen:
The X and Y chromosomes behave in a special way during the first meiotic prophase in mammalian spermatocytes. While the autosomes fully synapse -through the formation of synaptonemal complexes-, the heteromorphic X and Y chromosomes synapse only partially and form the XY body (Solari, 1974). In mammals, the synaptonemal complex is a highly conserved protein structure and is essential for synapsis, maintenance of integrity of the chromosome cores and meiotic recombination. The aim of the present work is to analyze the structural and functional variations of the chromosomal axes of the XY pair in mammals.Testicular tissues from adult males of the different species of mammals (Cavia porcellus, Galea musteloides, Felis catus, Canis familiaris, among others) were analyzed by optical/electron microscopy and immunofluorescence of meiotic proteins involved in synapsis (SYCP3, SYCP1, SYCE3), sister-chromatids cohesion (SMC3), meiotic recombination (MLH1) and chromatin silencing (BRCA1, γ-H2AX, 3meH3K27, RNA pol2). The comparison of the X and Y chromosome axes of the mentioned mammals show strikingly large, species-specific differentiations, which consist of thickenings, splittings, branchings, pearl necklace-like formations and loops. The unpaired axes of the XY pair undergo stepwise changes along pachytene substages. The transcriptional silencing and chromatin remodeling of the XY body are the basic and conserved mechanisms among mammals; however, variations in the structural components of the synaptonemal complex and unpaired axes were observed in a significant variety of mammals, from eutherians to metatherians. A deeper analysis of these variations and their functional aspects may give new prospects for research on the molecular structure of the components of the synaptonemal complex. Financial support: PIP CONICET 0683 (RBS-AJS).